E-Bodies.org Cuda Challenger Forum

This is on my 74 Challenger...   difficult to get accurate wiring diagram for the 74...  Plus pretty sure mine had been messed with to bypass the federal seat belt interlock system.     

My problem started with an intermittent no crank.   Thought probably no ground from neutral safety switch, but, with voltmeter tested the ground at starter relay (when it didn't want to crank) and had ground.   Then tested the Start wire to the starter relay, and with wife hitting the starter...No Power.    So, i traced wire back to the right must bulk head connector and pulled it off...there was fair amount of corrosion...so note to myself to later take the time to clean each spade and each female connector on that bulkhead (wires 17-24)   I also re-pushed together the flat wiring connector at the steering wheel... Reconnected and tried and it cranked right over and started right up...  Problem solved...or so i thought.

Next morning, Decided to take it for a morning spin, and it cranked over but sputtered several times before starting...  ok..it sometimes doesn't like being cold ...especially with that hot cam in it...   pulled out of driveway and down my street...and it stalled when i came to stop sign..  Cranked...and it sputtered to life, but noticed smoke coming from under hood...and it stalled again...   left it off and opened hood and saw that i had burned the insulation off of a wire in the under hood wiring harness..  Shit...   so with help of the wife pushed it back to garage.. 

I ended up taking off the bulkhead wiring harness completely and taking into the house to replace the bad wires and clean completely all of the spades.  ( i also cleaned all of the female connectors with emory boards, and spray contact connector cleaner spray.  In repairing harness I replaced the wire which was completely destroyed is the one from bulkhead connector #23 which runs to the main distribution point which then feeds the choke heater, voltage regulator, ballast resistor, alternator field terminal, and one of the ecu power points. 

I also, then repaired any other wire showing damage, and continuity checked every bulkhead connector to its end point on the harness, as well as every one of the 5 leads in the ecu to their respective ends.   So, with all of the continuity checks being good, the harness should now be good !!   I think!!.

Re-installed and engine will crank, but no start...(it is definitely getting gas).   I've put on a timing light while cranking but it never lights so the ignition system isn't firing.   

With ignition on i have probed with multimeter and have power to the positive post on coil and onto all four posts on the ballast resistor.   I have tried swapping coil and ECU thinking maybe they got shorted out during the wire melt down...   Still no start...  PS the spare ECU i put on has never been tested...   but what are the odds of both the original and new after market ECU being bad?   

Thinking ok, so with ignition on i have power to the coil and ballast, but what about during cranking that uses post 22 on bulkhead connector?   to eliminate this as a problem i turned on the ignition (run position) and then make it crank by bypass wire at the starter relay...still no fire, and checking with timing light...NO LIGHT NO FIRE!! 

Suggestions on what to check next?   This being a factory electronic ignition, is there anything in the distributor itself that might be fried ?  Is there a bench check for the ECU ...   ?  Distributor? 

   

CORRECTION...   If i turn the key to RUN not start and jumper the relay block to make it crank it will start !!   

Knowing this i then pulled off the start wire from the relay so engine wont crank, and also pulled BOTH ballast resistor connectors off.   With key in RUN i have power on the blue connector that jumps to the other side.   AND like .3 volt on the other ballast connector (the one that gets the start switch wire).    If i turn the key to Start then the power goes to zero on the RUN ballast connector and i get about 11 volt at the start ballast connector.    Sounds good...but with both connected on RUN i show 11.5 volt at the positive coil connector, but when i turn the key to start The voltage drops to zero at the coil positive connector.   No wonder it wont start...but why??   Do i have a short somewhere, or is the voltage i see on START connector phoney...i.e shows 11 volt but maybe no amperage??  i.e not passing enough current to run the coil and ecu ?   

I'd recheck and make sure the ignition switch connectors are clean..If they're black or corroded you'll have an intermittant problem.. It's the wide,flat one under the steering column{there's two one is the turn signal connector}...Is the seat belt switch bypass something that needs attention ???

More tests...

Ran a wire from the starter relay positive cable to the brown wire on ballast (that is were the "start" wire makes firs contact).   Then turned engine over with key and it starts!!!!   So, i would say from that point on the harness and all components are good. 

Also, to verify that power is going thru (at least a little) i hooked up a DC 12 Volt motor i have that draws 2 amp...to the brown ballast wire with it disconnected from ballast...and turning key to start...it ran the motor fine!!   So at least two amps can go thru the start path...  Maybe that isn't enough or...why wouldn't it work all connected ?   

Have you replaced the ballast resistor?

@chargerdon (https://forum.e-bodies.org/mlist/chargerdon_451) You can get an excellent laminated wiring diagram for your car here. https://www.classiccarwiring.com/challenger/

Quote from: chargerdon on July 14, 2018, 06:18:43 PM
CORRECTION...   If i turn the key to RUN not start and jumper the relay block to make it crank it will start !!   

Knowing this i then pulled off the start wire from the relay so engine wont crank, and also pulled BOTH ballast resistor connectors off.   With key in RUN i have power on the blue connector that jumps to the other side.   AND like .3 volt on the other ballast connector (the one that gets the start switch wire).    If i turn the key to Start then the power goes to zero on the RUN ballast connector and i get about 11 volt at the start ballast connector.    Sounds good...but with both connected on RUN i show 11.5 volt at the positive coil connector, but when i turn the key to start The voltage drops to zero at the coil positive connector.   No wonder it wont start...but why??   Do i have a short somewhere, or is the voltage i see on START connector phoney...i.e shows 11 volt but maybe no amperage??  i.e not passing enough current to run the coil and ecu ?   

You've got it! The reason is that you are using a volt meter, by nature they draw a VERY small amount of amperage. You can use it to test the ignition system but the circuit must be "loaded". There is an easier way however- use an old school test light probe for this test. They are available for cheap in any auto parts store. It looks like an ice pick with a bulb in it and a wire coming out of the handle. There is an alligator clip on the end of the wire. Attach the clip to a good ground and carefully insert the probe into the connector you want to test. Switch on the key and the bulb lights up loading the circuit for you indicating voltage and amperage.
  You have done some thorough testing already, nice job! I think you will find that you have high resistance on your Hot-On-Start wire (usually brown ). You have already proven this out by wiring to the start solenoid. Sorry for your frustration, I hope this helps! :bigthumb:

I have a test light, but that isn't good enough.   I.e. I tested my test light for amperage and it draws less than .1 amps for the light.   The ignition system draws between 5 and 6 amp.   So it can light up and still not be passing anywhere near enough current.. 

Quote from: chargerdon on July 21, 2018, 11:30:42 AM
I have a test light, but that isn't good enough.   I.e. I tested my test light for amperage and it draws less than .1 amps for the light.   The ignition system draws between 5 and 6 amp.   So it can light up and still not be passing anywhere near enough current..

Ok then in that case, you can use a bulb with a larger amp draw like an 1156 or the "bright side" of an 1157. Another option is to use your volt meter with the circuit connected (loaded) to the start side of the ignition system. Disconnect the start relay so the engine won't crank, have someone hold the key switch in the "start" position. Check the voltage available at the ignition start circuit with the full 5-6 amp current flow.

Ok....anybody know how difficult it is to replace the ignition switch wiring and harness??   Any body have instructions for this? 

1) do have to remove the steering wheel? 

2) how do you get the key lock mechanism out? 

The reason i ask is that today, I Tapped onto the brown wire that goes into the flat ignition connector, and ran this wire thru the firewall and into a tap i but on the brown wire (start wire) at the ballast resistor.   Then using the key switch tried to start the car, but, she would not start.   I then put my amp tester in line and when i try starting it is only reading about .6 amp.   I thought maybe most of the current is following the normal path thru the bulkhead connector...   i.e two paths..So...

i then removed that bypass and put my amp meter between the ballast resistor and the normal start wire and read about 2.5 amp...  so 2.5 and .5 is only 3 amp...   wish i knew what the minimum was to fire the coil and operate the ecu.   

Ok. so to prove to myself that i'm not all wet, i repeated putting a wire direct from battery post into the brown start  wire connector, and hit the key and she started...   Running it thru my amp gauge showed almost 11 amp...

Based upon this,  feed int starter wire directly from battery, car will start on key, but the bypass wire from take on ignition switch into its flat connector wont...   I am now believing that it isn't the wiring but the ignition switch itself is going bad. 

So... I see a new one on ebay for $33 not all that expensive...  but will need help figuring out how to replace it!   I have never taken a steering wheel apart.   

Does anyone agree with my conclusion...or should i still look elsewhere? 

Do you have access to a spare column/switch? I'd plug one in before I would dig into the column & replace the switch.....  Also be aware the aftermarket switches are crap.... I'd source a original be it NOS or used long before I'd deal with an aftermarket switch... Way to much work to change it to put in a POS... 

Quote from: 1 Wild R/T on July 22, 2018, 01:22:01 PM
Do you have access to a spare column/switch? I'd plug one in before I would dig into the column & replace the switch.....  Also be aware the aftermarket switches are crap.... I'd source a original be it NOS or used long before I'd deal with an aftermarket switch... Way to much work to change it to put in a POS...

I agree! Most of the aftermarket stuff is crap, unfortunately. I had issues with a turn signal switch, brand new aftermarket, it was miswired at the flat connector. It cost me 3 hours of wtf? head scratching. I would suggest the same, look for NOS or even a Standard-Blue Streak option. I wound up getting a turn signal switch from YearOne,(Dave at Rosville would have been better)  worked just fine. I think you have found your problem anyway! Congrats!

Mmmm   No i don't have a spare switch...   tho if i buy a new one, it sure is a good idea to plug it into the harness before installing to see if it truly fixes the problem.   

Regarding OEM vs reproduction, first i do not see any oem switches on ebay or rock auto or any of the parts stores...their all aftermarket.   I do see two differences....   The illustrations for all of the switches i have found on ebay and rock auto...  all show a 8 pin connector but two of the connectors are empty making it a six wire system.   Mine is 8 wire !!    In addition the aftermarket all show wire 2 the black wire that goes to power the fuse panel, and the main power in red wire are not in the connector...so that you can bypass the flat connector...i suppose to cut down on heat in the flat connector.  Mine are in it...so i could push them in...  or pull out of other side and do a bypass of the connector for those two. 

b) The smaller wires 7 and 8 are not there at all !   I.e all of them are only 6 pin harness and connector.   My car has wires 7 and 8...   wiring diagram shows pin 8 black wire as going to the left door switch...  (i think for the ignition switch courtesy light which my car has and it does work...   and pin 7 has two orange wires ...one goes to a bus for the other interior lights... ash tray and glove box...  both of those are functional...  i this it was an order package i believe...   

So right off the bat the aftermarket switches are incomplete.  Because of this and the work involved, and not knowing for sure it that is the problem.........

I am soooo close to buying another starter relay for about $10...   giving it solid ground, power in from the main battery post on the existing starter relay,  the trigger wire tied to the current starter trigger wire on starter relay and the out would be strung to the ballast resister...   I think the starter start wire has enough power to trigger a this relay, that would send straight battery to the start wire on the ballast.   Hmmmm   Certainly not stock...but i think it would work...   Would be a lot cheaper and easier than replacing the starter ignition switch...especially if that didn't actually cure the problem.     

Two negatives...one not stock.... someday could cause me to lose a car show, and secondly if the ignition switch is at fault, then it might crap out completely later and need replacing anyways...   Hmmmmmmm

 Aftermarket issues! I agree, they suck! As for your bypass idea, yes i think it will work. GM has done it that way (indirectly) for years. The principle is the same and electrons don't care. As you mentioned, it's not Mopar OEM design though. Your choice on this one!

Quote from: chargerdon on July 22, 2018, 10:42:49 AM
Ok....anybody know how difficult it is to replace the ignition switch wiring and harness??   Any body have instructions for this? 

The best guidance available is a deconstruction video that @Cuda Cody (https://forum.e-bodies.org/mlist/cuda-cody_1) put together for the site.  You can find it near the bottom of this page:

https://www.e-bodies.org/videos/

The video is based on removal and dismantlemnt of the column which includes accessing the ignition switch.   It'll be snug doing it in the car but it appears possible (disclaimer:  I rebuilt my steering column removed from the car, not installed).

Quote from: chargerdon on July 24, 2018, 09:40:56 PM
734406PK  Also, on my attempt to bypass using a second relay..   the way i hooked it up was the new relay gets batt ground and trigger wire from the corresponding posts on the starter relay.    Then on new relay i have a heavy wire running from its sol (out post) to the ballast brown wire.   I know the relay is triggering, because i can feel it click when wife hits the key to start.   But for some reason this is different than putting brown wire directly on the battery.   Incidently with my ohm gauge i checked the new relay for amperage draw to activate it...less than 1/2 amp...     

Towmorrow, im going to take the entire harness out again, and ohm check each and every wire and trace where they go to...   For the third time...  and reclean all of the connectors..

I may be misinterpreting the relay connection but here is a generic wiring diagram:
http://hd-dump.me/wp-content/uploads/12v-30-amp-relay-wiring-diagram-with-717-2bakvzzhl-sl1500-new-12v.jpg

Relay terminals:
30   12 volt positive power feed-(constant hot)
85   12 volt ground
86   switched positive trigger- connect to brown wire
87   normally open contact, closes on trigger- connect to ballast, brown wire
and if you have a 5 pin relay-
87a  normally closed contact, opens on trigger- not used here, leave disconnected

This should work. When the brown wire goes hot, it will close the relay contacts sending battery power directly to the ballast, same as a jumper wire.

That is essentially what i did..   

Post 30...  ran jumper wire to post 30 Batt of starter relay
post 85...  ran jumper to post 85 ground of starter relay
post  86..  ran jumper to 86 key start trigger of starter relay
post 87   ran this to the ballast resistor where brown wire goes...  ie. onto 1.2 ohm side of ballast resister.

I know the new relay is firing as i can feel it when wife turns ignition switch to start...  but car cranks but isnt starting...  it should.

Only problem i can see is that i haven't disconnected the normal brown wire from key switch...  maybe the current is fighting itself?   

Could your ignition switch be bad?

This is not making much sense.

Well...the ignition switch certainly could be bad..i have a new one on order..   

Did the X-tra relay as a quick work around until the new switch arrives...   By putting in the extra relay fed from the starter relay and going to the ballast i should be essentially be bypassing all the wiring in the harness, bulkhead connector, and starter switch itself for start.    It should have worked but doesn't..   but if i manually use the same extra wire to ballast straight to battery, and crank via switch the car will start...   NONE of this makes sense...im pulling my hair out and about ready to commit hairy-kari..   

Quote from: chargerdon on July 25, 2018, 02:32:29 PM
That is essentially what i did..   

Post 30...  ran jumper wire to post 30 Batt of starter relay
post 85...  ran jumper to post 85 ground of starter relay
post  86..  ran jumper to 86 key start trigger of starter relay
post 87   ran this to the ballast resistor where brown wire goes...  ie. onto 1.2 ohm side of ballast resister.

I know the new relay is firing as i can feel it when wife turns ignition switch to start...  but car cranks but isnt starting...  it should.

Only problem i can see is that i haven't disconnected the normal brown wire from key switch...  maybe the current is fighting itself?

Ok looks good. Check for power at 87 when the relay triggers. I think something is wrong there.

Today, worked with a buddy...and we were able to plug in a new ignition switch into the switch connector at the steering wheel.  To see if that is the problem...  BUT no get the same results.   I.e   Car will crank from the switch but not start.   So doesnt seem to be ignition switch...   

I can make the car start in two different ways.. 
1) Leave ignition turned to on...and jumper the starter relay to make it crank and she starts right up.    So the "RUN" side is good.

or

2) jumper wire from battery to the brown start wire on ballast, and then either crank via the key or the starter relay jumper...   and she will start.   

So to me start way 1 and 2 both mean that from the ballast resistor back is good (including when attempting to start), and the run side is good...   Start side

If i leave the starter relay wire off, and use voltmeter right at the ballast brown wire i will read between 11.56-12.2 volts...  and if i leave starter relay on so she cranks then from the key...that voltage will drop to 9.5  (i guess the starter itself drops the voltage that much).   SO IT SHOULD start...   

new ignition switch made no difference.   

another test was using the new ignition switch...  i jumpered at the back of the switch the blue run, and brown start wires... then turned the ignition to crank...and she starts..   

One really weird reading i get, is with bulkhead connector removed, and ignition switch in off, if i measure voltage right at the bulkhead for start i read about .95 volt...it should be zero...   if i turn the ignition switch to start it jumps to 12.5...   i am worried about that .95-1.0 volt reading with key off.   Could the wires in passenger side of bulkhead have been damaged?    plus reading good voltages is nice but no guarantee she will pass enough amperage. 

That is my next step...to pull passenger side bulkhead down far enough to examine those wires for "melt" damage.   

any other suggestions?

Quote from: chargerdon on July 14, 2018, 06:18:43 PM
CORRECTION...   If i turn the key to RUN not start and jumper the relay block to make it crank it will start !!   

Knowing this i then pulled off the start wire from the relay so engine wont crank, and also pulled BOTH ballast resistor connectors off.   With key in RUN i have power on the blue connector that jumps to the other side.   AND like .3 volt on the other ballast connector (the one that gets the start switch wire).    If i turn the key to Start then the power goes to zero on the RUN ballast connector and i get about 11 volt at the start ballast connector.    Sounds good...but with both connected on RUN i show 11.5 volt at the positive coil connector, but when i turn the key to start The voltage drops to zero at the coil positive connector.   No wonder it wont start...but why??   Do i have a short somewhere, or is the voltage i see on START connector phoney...i.e shows 11 volt but maybe no amperage??  i.e not passing enough current to run the coil and ecu ?   

Check the voltage at the coil positive terminal with the key switch in the start position. You should have battery voltage there while cranking. The brown wire that is hot while cranking at the ballast is also common to the coil positive terminal.

734406pk    Yes i have that diagram...   putting multimeter on the brown (start) lead at ballast with starter relay disc, i read 11.75 volt...with starter relay wire connected and engine cranking...i read 9.6 volt...   that should be more than enough to start car.   But it cranks and wont start.   But my theory is even tho i read good voltage...and there enough of a connection for a good amperage draw? 

Tomorrow, i'm disconnecting the bulkhead connector and putting three jumpers...into the bulkhead on firewall...   
1) to Starter relay to get cranking
2) pin 23 (start) directly to brown start wire on ballast.
3) pin 22 (run) directly to the blue (run wire) on ballast.

The above will eliminate my repaired engine harness to bulkhead...  and try to start ...if she does, then it must be somewhere in my repairs.   If she doesn't (and i'm betting it wont) then it has to be between the bulkhead connector and the ignition switch flat connector.   Now if that is the case... im going to have to disconnect all of the connectors at bulkhead on engine side...and show the entire thing in and hope i can pull it down till i can see any obvious damage to the wires on that side.   YUK...  I just love working on my knees...

Sounds like a good plan. I was reading one of your previous posts (quoted) and if I'm understanding it correctly, you have power at the brown wire ballast connector but zero volts at the coil positive. Is this the case?

No...  I have power at both...  thats why its so baffling...it should fire..   Im still thinking that while i show volts...there isnt enough amperage thru the brown wire.   

Wow. Difficult to deduce a logical clear path to your problems.  Some of your tests seem to contradict themselves at different times. So I'm thinking you must have additional overheating problems within your wiring. Perhaps the wiring at your B/H connector on the cabin side? You appear to have eliminated all other components as being the problem.

I had to wire the ballast resistor as the photos show to get it to start.
I have not checked or compared it to a wiring diagram to understand why it needed wired like this to run.
Plan to spend some time this week reviewing if the way I had to make the connections is actually per standard wiring.

Quote from: chargerdon on July 29, 2018, 03:29:59 AM
No...  I have power at both...  thats why its so baffling...it should fire..   Im still thinking that while i show volts...there isnt enough amperage thru the brown wire.

Ok so you have battery voltage to the coil positive terminal and the brown wire on the dual ballast while cranking, just needed to be 100% clear on that. You also need to see battery voltage (or slightly less due to the ballast resistance) to terminal #1 of the ignition ECU while cranking (VIA the run ballast connector). The brown wire needs to be connected to the low resistance side of the ballast (.5 - 1.2 ohms).

Also- do you have a 5 pin or 4 pin ECU?

Quote from: 73440 on July 29, 2018, 07:09:03 AM
I had to wire the ballast resistor as the photos show to get it to start.
I have not checked or compared it to a wiring diagram to understand why it needed wired like this to run.
Plan to spend some time this week reviewing if the way I had to make the connections is actually per standard wiring.

It looks like you are missing a jumper wire in the ballast connector. The dark blue wire (Hot in run position) and the light blue (power to ECU terminal #1) need to be connected together and installed onto the ballast low ohm side with the brown wire. This is where the run and start circuits combine to power the ignition system.

734406PK  and anyone...   OK there have been a lot of posts...let me recap all of my tests and efforts.

All started with a meltdown of a couple of wires on the engine wiring harness.   I pulled harness and replaced any burnt wires (primarily the main "run wire" into the junction point in harness, and the start wire right beside it).  I then continuity tested each and every one of the 8 Bulkhead connector wires and the main points on the engine side 8 pin to connector.   

After repairs put harness back in and the engine will crank from the ignition key but not start.   I can make the engine start by two methods.  1) with key off, run bypass wire to brown (start) wire on ballast direct form pos post on battery, and then force crank by jumper wire on starter relay.  or 2) with key on jumper the starter relay for force crank.   Either way she will start.   

Ok, today I tried a new ignition switch connected in at the connector (not into the steering wheel) and pretty much got the same results so I can rule that out.   However, i was getting some inconsistencies when testing like this, so went back to the original ignition switch in the steering wheel, but, i also cut out the Brown (start) wire on both sides of ignition switch connector and spliced it together..   Inconsistencies gone.   

Second I have the 5 pin ECU and have tried a spare for it, and a spare ballast resistor...   Same results.   

My system is wired like the diagrams a and b found on my mopar for 74 challenger (http://www.mymopar.com/downloads/1974/74ChallengerA.JPG).    The problem with that diagram is that it doesn't show the ballast NOTCH so you cant figure out which side of the ballast is the 1.5 ohm side and the 5 ohm side.   However if you look at the 5 Pin ECU picture in http://www.chargerr.com/Ignition/Ignition.htm it logically is like that one.  In other words i have the Brown (start) wire on the 1.5 ohm side, the green ecu wire on the 5 ohm side, and the little jumper across the 1.2 and 5 ohm with the blue (run) wire.   (see my picture).   

Now here are some readings taken today:

Volts
My Batt shows 12.35 volt.  Below tests were done with starter relay wire off so no cranking.
with key in RUN   i show at the blue post on the ballast 10.85 volt and at the brown wire 4.9 volt
with Key turned to "start" Blue wire at ballast shows 6.88 volt and brown wire 10.8   (note if i pull the Blue connector off of the ballast then i show 12.2 volt at the brown wire so i assume that the current draw from the choke heater, VR, alternator field, and ECU account for the voltage drop at the ballast).

AMPS
disconnecting neg cable from battery and running thru amp meter between negative cable and negative battery post is show
key off  .001 amp
key to run 5.1 amp
key to start 5.1 amp.

One interesting point is that my multimeter shows 5 amp draw at battery, for both run and start (no cranking as starter relay wire pulled), but with battery hooked up and looking at my amp meter in the car, when turning key to run i show some discharge as expected, and when turning it to run an even deeper discharge...    That doesnt agree with multimeter hookup. 

Ok, so i've got volts and amps on the brown wire SO WHY THE HELL wont she start?

Lastly, as a test not trusting my multimeter,  i have two DC electric motors...  Taping off of the ballast brown wire and into the motors (wired in parallel) and then to neg battery they both run when key turned to start...so amperage is there.   Running thru my amp gauge the two motors draw about 4.5 amp..   So i have at least that amount of current capable at the brown ballast.   

Also, i have ohm continuity tested the Pin 1 on ecu connects with near zero resistance to the blue, start wire, and the dk green red wire other side of brown wire goes to pin 3 on ecu (counting clockwise from pin 1...pin 1 being the top of the mopar pentastar. 

Lastly, while it didn't pull the cabin side of the Bulkhead connector off, i was able to look with a strong flashlight at it (talk about discomfort twisting yourself) and it LOOKS 100% clean.   I.e no visible signs of overheating or melting or black spots etc.   

I'm stumped...     

Quote:

Volts
My Batt shows 12.35 volt.  Below tests were done with starter relay wire off so no cranking.
with key in RUN   i show at the blue post on the ballast 10.85 volt and at the brown wire 4.9 volt
with Key turned to "start" Blue wire at ballast shows 6.88 volt and brown wire 10.8   (note if i pull the Blue connector off of the ballast then i show 12.2 volt at the brown wire so i assume that the current draw from the choke heater, VR, alternator field, and ECU account for the voltage drop at the ballast).

You are dropping about 1.5 volts @5.1 amps through your key switch circuit for some reason. 6.88 volts on the blue wire while in the start position is very low also for an instant reading. Try jumping out your ballast resistor on the brown to blue side. This will apply battery voltage to the coil positive terminal and pin 1 of the ECU while cranking. 6.88 volts (and even lower with the starter draw) may be too low to fire the ECU.

734406pk...  yes, if i jumper the brown at blue wires at the ballast it will start on key !!  (of course i cant leave it that way without suffering premature wear out on the coil).  By doing this im showing 9.9 volt on brown wire with key in run...vs 4.89 volt without the jumper.   

So what does this mean??   

Also,  To try i took the 4 pin ECU out of my charger...which i think is good...but..who knows...as the charger is down right now..    and with it in i cant get the car to start no matter what i do...   From what i read you should be able to put a 4 pin in the 5th pin in ecu wont be functional, but, it is supposed to take care of that internally...   or with a 4 pin do i have to do something else??   Is distributor the same on 4pin vs 5 pin...   I know ballast is different but that side (5 ohm) simply should not matter with the 4 pin.    Am i missing something?

I believe you have something wired backwards.

The intent is when you turn the key to start the car you have FULL VOLTAGE 12.6 or very close to it. Once the car is running the ballast steps in and drops the voltage to 8-9V - this is done so the coil will have a long life and not die because you are running it at 12+V all the time.

You need full voltage to start the car so check all connections in each step (key on, ignition start, run) and report voltages back here. As well, when you are going through this give voltages at each side of the ballast and the coil.

Hope this helps a bit.

HP-Cuda...  yes...ive been working on it...somewhere there is a voltage drain.   As an experiment i measured amperage at the battery with key in run...   it draws 5.1 amp... like i said earlier.   But,  If i disconnect both the choke heater wire, and the VR to take alternator off that amperage draw drops to about 3.6 amp.   So those two draw about 1.5 amp.   If i leave both of them off, the voltage rises and the car will start from key. 

Or if i jumper the blue (run) wire on ballast to the brown (start wire on ballast) effectively taking out the 1.2 ohm resistor to not only the coil but also to the ECU...she will start on key.

Lastly, if with battery a little low and battery charger on it...i will read 14.3 volts at the battery and an extra volt or two at ballast resistor and she will again start from key.    734406pk told me it takes at least 9.6 volts to the ecu pin one to get it to fire the coil...  i read that, but, when cranking it drops below that thru the brown wire...   

So, my conclusion is everything is wired correctly, but, somewhere there is a voltage drain...just a little...enough to not fire the ecu and cause no start...   its that close to working..   Now the hard part...finding the current (voltage loss).   

Well you can do what I need to do pretty soon.

Remove the negative battery cable and while the key is on check the voltage between the post and the disconnected negative cable. This will show the voltage drop you are experiencing. You can also set your multi-meter to check amperage and see what kinda draw that is as well so either way will help you diagnose this problem. Next you start pulling fuses one by one to see which culprit is giving you problems. Then fix the problem and presto chango you are in business!

:wrenching:

Success...   sort of...  Band aid solution was to replace the 5 pin ECU with a new 4 pin...   

First...a big..big ...thank you to 734406PK...   he worked with me relentlessly in tracking down that the problem is a general voltage drop of about 1-1.5 volt thru my system not the ignition system wiring.  They reason it would start on run when jumpering the starter relay to start cranking is that the 1.5 ohm of resistance in bulkhead is eliminated to the ECU pin 1  ..it gets full voltage on run.   THANKS AGAIN 734406PK !!

Ok, one of the things i noticed in testing was that the ECU itself was consuming quite a bit of power.   So, even tho i was on a spare ECU which acted the same as the original...   I decided to purchase another new one.   This time a 4 pin ECU which would simplfy the wiring...ie. 5ohm resister side no longer needed with the 4 wire ECU.     

Putting in the NEW ECU (bought Masterpro brand at Oreilleys ($22.95) simply because it was inexpensive to try and was about the only one in stock at any of my local part stores).   Put it in and before even trying to start I measured the voltage at the brown wire with key in run...and it was about .4 volts higher than what it was with the 5 pin ecu.   Started the car via my relay jumper to make sure this ECU was even working...   Then tried the key start ...and HOLY COW...it started.   I guess that .4 volt gain was enough to cause the ecu to fire.  And starts quickly every time now.   So, this in itself is not a fix...but..luckily draws less power and therefore will fire from key.   

I still am going to pull the gauge cluster and measure voltage on the battery side of the amp gauge and the alt side of the amp gauge.   From all of my testing the probability is that the amp gauge getting old was beginning to put resistance into the circuit and maybe my harnsess meltdown...spiked it to be even worse.   So, will test this theory.   While i have it apart... tie the two amp wires together as the first step in the Amp Gauge bypass.   (ill buy a cheap cigarette lighter plug in voltage gauge for an interim solution to knowing if the charging system is working).   Later ill run the Alternator to Starter relay bypass.     

I read somewhere that Sunpro makes a voltmeter that can be bolted into the spot where the ammeter is located, inplace of our ammeter one wire then to ground.   Anyone know what Sunpro model it is and who sells it?

Sun Pro Model CP7985 is the one I think your referring to. Purchased one from Amazon just a few weeks ago, as I'm planning on doing the same conversion.

Just read this thread and had a similar thing happen to me on my old '87 van.  I was told (by an "old" mechanic) there are two "sides" to the ECU.  A "start" side and a "run" side, and one side operates independent of the other.  My problem was that I could start the van, but it would cut off as soon as the "start" side released.  I believe this may be why you were able to get it to start when you bypassed the "start" side of the ECU, and why replacing the ECU resolved the problem.

If the ECU had internal damage, this may have led to a number of the electrical gremlins you were experiencing when you were troubleshooting, and why you were misled throughout your troubleshooting process.

Just my  :alan2cents:

Hope this is helpful.


MIKE
fantum

About 2 yrs ago i had a starting problem with my 66 Charger.   

It would "fire" from key and then die...  over and over.   Finally found the "run" wire wasn't making good contact with the ballast.   Cleaned put it back on ...and problem fixed.   

So, now i've had both.   I would love to chat with a Chrysler engineer...and ask them "why do you not send power over the Run wire" when cranking?   Without it the car has to start with a 1.2 ohm resisted ECU...   DUMB !!  Or maybe there is a valid reason..but...i sure cant think of one.   

Quote from: chargerdon on July 30, 2018, 03:46:12 PM
   But,  If i disconnect both the choke heater wire, and the VR to take alternator off that amperage draw drops to about 3.6 amp.   So those two draw about 1.5 amp.   If i leave both of them off, the voltage rises and the car will start from key. 

The removal of 1.5 amps of load from your battery should not affect the voltage to any significant degree. The battery voltage probably does not change. You still have a high resistance connection somewhere in the start wire path. I suspect it is inside the cabin and/or BH connector.
The red wire supplying the battery voltage to the interior could be your culprit as well. Was it involved with the meltdown?

Dodj...Disagree...  1.2 OHMS not amps make a big difference in voltage.  Do a google search on OHMS law and you will see.   Yes, there is still a voltage drop somewhere...   I've ordered a voltmeter to replace the ammeter...  when it gets here ill pull out the gauge cluster and do some more investigating.

No, to the best of my ability to see with a flashlight to the drivers side of the bulk head, there isnt any visible damage to the bulkhead passenger side.   BUT, when i pull the gauge cluster i will be able to tell better.   

Maybe you misunderstood me.
What I am saying is the load you are talking about is not enough to cause a battery in good condition to loose the ability to supply you with 12vdc. So your supply is likely not changing so the voltage drop (caused by ohms that should not be there) is within the wiring. I believe we are in agreement.  :bigthumb:
If it were me, I would check the red wire at the column connector while under load. Should be battery voltage. Or very close.
Next with the key in the start position I would check the start wire voltage at the column connector. Should be close to battery voltage.
If all is good I would move to the engine side of the B/H connector and check the start wire voltage there. You are loosing it somewhere. Just a matter of meticulously following the cct. Which can be time consuming...


P.S. I've been an electrician for 30 years....

Quote from: dodj on August 06, 2018, 08:07:30 AM
Maybe you misunderstood me.
What I am saying is the load you are talking about is not enough to cause a battery in good condition to loose the ability to supply you with 12vdc. So your supply is likely not changing so the voltage drop (caused by ohms that should not be there) is within the wiring. I believe we are in agreement.  :bigthumb:
If it were me, I would check the red wire at the column connector while under load. Should be battery voltage. Or very close.
Next with the key in the start position I would check the start wire voltage at the column connector. Should be close to battery voltage.
If all is good I would move to the engine side of the B/H connector and check the start wire voltage there. You are loosing it somewhere. Just a matter of meticulously following the cct. Which can be time consuming...

You are spot on dodj! Chargerdon has already traced down the voltage drop to the passenger compartment and corrected a few resistances along the way. It is in between fuse link terminal 16 (interior) and the keyswitch feed wire, 1-1/2 volt drop. We suspect it may be the ammeter but the instrument panel needs to be removed for access.
:bigthumb:


P.S. I've been an electrician for 30 years....

Quote from: 734406PK on August 06, 2018, 09:10:25 AM
Chargerdon has already traced down the voltage drop to the passenger compartment and corrected a few resistances along the way. It is in between fuse link terminal 16 (interior) and the keyswitch feed wire, 1-1/2 volt drop. We suspect it may be the ammeter but the instrument panel needs to be removed for access.

In the wiring close to the ammeter is a five way junction that may be worth looking at. :alan2cents:

Quote from: dodj on August 06, 2018, 09:36:59 AM

Quote from: 734406PK on August 06, 2018, 09:10:25 AM
Chargerdon has already traced down the voltage drop to the passenger compartment and corrected a few resistances along the way. It is in between fuse link terminal 16 (interior) and the keyswitch feed wire, 1-1/2 volt drop. We suspect it may be the ammeter but the instrument panel needs to be removed for access.

In the wiring close to the ammeter is a five way junction that may be worth looking at. :alan2cents:

:iagree: It carries the car's entire electrical load. :o

 :popcorn:

 Any updates chargerdon?

The Sunpro voltmeter should be here any day...  will probably pull out the dash gauges this weekend...  and start the process of testing. 

Meanwhile, car is running just fine...   

Crap !!   Package arrived this morning...  It is a SunPro AMMETER..in the Voltmeter package...   sent email to vendor to resend the correct one.   Damn.. 

Quote from: chargerdon on August 22, 2018, 09:01:13 AM
Crap !!   Package arrived this morning...  It is a SunPro AMMETER..in the Voltmeter package...   sent email to vendor to resend the correct one.   Damn..

OMG they still make ammeters? Oh well, standing by  :bigthumb:

Ok...   took dash gauge cluster out...   measured volts at ammeter both sides...and got battery voltage with key off.   With key on Battery side showed 11.75 volt and alt side showed 11.5   so some .25 volt loss here. 

Also bit the bullet and pulled the bulkhead connector off on passenger side.   Glad i did.   The Battery wire looked real good, but, the alt (black wire) showed several spots were the insulation was melted off, and one spot where it and the Run wire wire partially fused together.   Ill bet there was some loss there also.. 

Also, the windshield wiper wires were a mess !!  (it still worked but could have been part of the problem).    Pulled the alt wire out of harness and taped it up good...  (left it out as doing the ammeter bypass it wont be needed).   Repaired the wiper wires with tape and two new connectors..

Also taped up the "run" wire.

Removed ammeter (bolted the two leads together) and lots of tape...   and put in a voltmeter in its place..power fed from an accessory lead and ground to dash board.    (had to cut out the back of the gauge dash to make the voltmeter fit for depth, and fit it into a spare BLANK (clock blank) to make it work...it looks good.) 

Then put the bulkhead connector back in and reassembled the gauge cluster.

Put in a 10 gauge bypass wire from alternator (removing old alt wire) and ran it to the starter relay.

Car is now starting almost instantly !!   The voltage gauge shows about 12.3 volt (battery read) when turned to accessory, and 11.8-11.9 volt with key on and with engine running 13 volt at idle and 14.0 volt above 1000 rpm !!   Haven't tried the headlights at night to see if any different...but...wow...car is starting almost instantly.   Wish i had done this a year ago..   

I now have a working ammeter i can sell if anyone wants one ! 

 :clapping:
Glad you got it all sorted out.

 :banana:

:woohoo:

Congrats! Glad you got it sorted out!

A good thread.. i'm planning to install a volt gage.

It wasn't that hard.   I got a 2 inch voltmeter i know they said Sunpro...  but i bought a cheaper unit off of ebay mostly because i liked the gauge face better...reads 8 to 16...so face is larger in the 12-14 volt range than the Sunpro..   

to install in the ammeter location (standard gauges)  .   I used the blank plate spare that i had and cut the 2 inch round hole in it and  i had to cut out the back of the gauge cluster cage (voltmeter deeper than the ammeter) and found a switched power source and hooked it up along with its internal light...  Bolted together the ammeters red and black wires and heavily taped it.   Pulled the alternator (black wire out of the bulkhead harness and taped off.   Then ran a 10 gauge wire from alternator (after removal of original wire from alternator) and ran it to the starter relay batter post.   Done.    Works well... 

FYI, they make USB chargers that go into the cigarette lighter, and may have a voltage read-out.

Quote from: chargerdon on September 10, 2018, 12:58:04 PM
Ok...   took dash gauge cluster out...   measured volts at ammeter both sides...and got battery voltage with key off.   With key on Battery side showed 11.75 volt and alt side showed 11.5   so some .25 volt loss here. 

Also bit the bullet and pulled the bulkhead connector off on passenger side.   Glad i did.   The Battery wire looked real good, but, the alt (black wire) showed several spots were the insulation was melted off, and one spot where it and the Run wire wire partially fused together.   Ill bet there was some loss there also.. 

Also, the windshield wiper wires were a mess !!  (it still worked but could have been part of the problem).    Pulled the alt wire out of harness and taped it up good...  (left it out as doing the ammeter bypass it wont be needed).   Repaired the wiper wires with tape and two new connectors..

Also taped up the "run" wire.

Removed ammeter (bolted the two leads together) and lots of tape...   and put in a voltmeter in its place..power fed from an accessory lead and ground to dash board.    (had to cut out the back of the gauge dash to make the voltmeter fit for depth, and fit it into a spare BLANK (clock blank) to make it work...it looks good.) 

Then put the bulkhead connector back in and reassembled the gauge cluster.

Put in a 10 gauge bypass wire from alternator (removing old alt wire) and ran it to the starter relay.

Car is now starting almost instantly !!   The voltage gauge shows about 12.3 volt (battery read) when turned to accessory, and 11.8-11.9 volt with key on and with engine running 13 volt at idle and 14.0 volt above 1000 rpm !!   Haven't tried the headlights at night to see if any different...but...wow...car is starting almost instantly.   Wish i had done this a year ago..   

I now have a working ammeter i can sell if anyone wants one !

Nice job chargerdon! You never gave up and you have found the issue! Congrats and enjoy your MOPAR! :worship:

Thanks Andy !!   

 :clapping: