I'm trying to troubleshoot a possible weak spark issue and I think I made some mistakes with engine grounding.
The engine is a 440 with Stealth aluminum heads.
On previous engines with steel heads I grounded the negative battery cable to either the front intake bolt, the block or the head.
I thought the aluminum heads wouldn't be a good source of ground so I ran the neg. battery cable down and bolted it to the K member, so basically there is no ground going to the engine.
I'm not sure if this lack of a good engine ground would cause the engine to run ruff but I would guess it doesn't help.
So I'm going to move the neg. battery cable to either the front intake bolt, somewhere on the aluminum head or somewhere down on the engine block.
With the aluminum heads where would be the best place to run neg. battery cable for a good engine ground?
Should I run a second ground strap somewhere on the engine block, heads or firewall?
Thanks for any advice.
I ran the ground on the BB car I'm building to the water pump bolt. But it doesn't have power steering. I have seen them on the front exhaust bolt. I think there is a threaded hole where the intake sits at the very front on the head. If you have the extra ground wire on your battery cable you won't need one on the firewall. If it doesn't you will need one. Aluminum heads are just fine for grounding.
Quote from: Shane Kelley on September 28, 2017, 05:17:40 PM
Aluminum heads are just fine for grounding.
Yup. Aluminium is a good conductor. My engine grounding is from the passenger head to the firewall.
The spark plugs are screwed into the heads, they better conduct electricity... Treat it the same as iron heads, bolt the ground in the stock location & there needs to be a connection to the body too, whether it is bolted to the engine & body or from the battery to the body doesn't matter....
I have Super Stealth heads and I ran the negative to the back of the power steering bracket.
Super ground, not one problem.
Add some engine to chassis ground straps like these. They are often go missing over the years. They connect from the bell housing bolts to the frame and body. Good cheap insurance!
www.amazon.com/Dorman-HELP-60213-Ground-Straps/dp/B000CO968G/ref=pd_bxgy_263_3?_encoding=UTF8&psc=1&refRID=JD07RMKBHM2K8HFCAW1K
Can't have enough grounds. Work on German car sometime. :rebelflag"
Quote from: 734406PK on September 29, 2017, 05:29:07 PM
Add some engine to chassis ground straps like these. They are often go missing over the years. They connect from the bell housing bolts to the frame and body. Good cheap insurance!
www.amazon.com/Dorman-HELP-60213-Ground-Straps/dp/B000CO968G/ref=pd_bxgy_263_3?_encoding=UTF8&psc=1&refRID=JD07RMKBHM2K8HFCAW1K
LOL
I just bought that exact ground strap tonight at my local parts store.
I need to find a good location between a bell housing bolt and the frame to mount it.
Thanks for all the good advice.
I'm going to attach the large wire on the neg. battery cable to a threaded hole on the front of the driver's side head.
The smaller diameter wire on the neg. battery cable is mounted/grounded to the radiator support in the stock location.
I'm going to mount a ground strap from a transmission bell housing bolt to somewhere on the frame.
I was also thinking of running a ground wire between the aluminum heads at the back of the engine, overkill?
Extra grounds won't do any harm..
You can't really overdo grounds but you won't really need the extra one.
Quote from: GrandpaKevin on September 29, 2017, 06:08:59 PM
Thanks for all the good advice.
I'm going to attach the large wire on the neg. battery cable to a threaded hole on the front of the driver's side head.
The smaller diameter wire on the neg. battery cable is mounted/grounded to the radiator support in the stock location.
I'm going to mount a ground strap from a transmission bell housing bolt to somewhere on the frame.
I was also thinking of running a ground wire between the aluminum heads at the back of the engine, overkill?
Run a ground strap from a flywheel housing bolt right to an ignition control unit attaching screw if it will reach.
Quote from: GrandpaKevin on September 29, 2017, 06:08:59 PM
Thanks for all the good advice.
I'm going to attach the large wire on the neg. battery cable to a threaded hole on the front of the driver's side head.
The smaller diameter wire on the neg. battery cable is mounted/grounded to the radiator support in the stock location.
I'm going to mount a ground strap from a transmission bell housing bolt to somewhere on the frame.
I was also thinking of running a ground wire between the aluminum heads at the back of the engine, overkill?
That's exactly how I did mine, minus the ground at the back of the engine.
Well I got the grounds connected but unfortunately I'm still having running issues.
I'm sure correcting the grounds was needed so now I want to continue checking the ignition system to the best of my limited abilities.
The car seems to start and run/idle OK when cold but when the engine temp gets to about 160 degrees the car's idle gets a little rough an wants to stall.
It will restart but seems to run rough and will stall when put in gear.
I'm running a HiRev Mopar type ECU with dual field ballast and Blaster 2 coil
I did a quick check with a volt meter and with the key in run position and engine warm voltage to the + side of the coil is around 3.6
With the car idling volts to the coil are around 5 when the engine is revved volts go to 7.5 to 7.8.
Do these numbers seem right?
Thanks.
You should be 5v + all of the time at the coil .
are you bulkhead connections good ?
Engine wiring harness is new from Year One.
The bulkhead connectors looked good, (nothing looked burnt and no corrosion) when I installed the new harness.
Quote:I did a quick check with a volt meter and with the key in run position and engine warm voltage to the + side of the coil is around 3.6
That reading is way too low. Try the Hi-Rev test:
Pre-startup test (recommended for vehicles that has experienced Ignition Control Failure). Connect a voltmeter between the coil positive (+) and a good ground. Turn ignition key to "run" position. Voltmeter should read between 7.0 and 9.0 volts. If higher turn ignition key off immediately and check ballast resister (resistance - too low 0.5Ω minimum, 1.0Ω recommended for most street applications), ballast wiring, shorted coil, ignition switch wiring, etc.
I wouldn't expect the engine to run well with 3.6 coil volts.
Thanks..
Very confusing.
I decided to check voltage at the coil on my other Challenger and I was surprised to see it was also around 3.5 with the key on.
This car has a 440 engine with similar ECU, Blaster 2 coil and dual field ballast.
All the ignition parts on that car are much older and the car has run good for years. :thinking:
I looked for a blue wire coming out of the bulkhead, found a blue wire with white stripe?, this wire had 11.5-12volts with key on.
Also found similar 11+ volts at the blue wires at the ballast with key on.
I'm not sure if this correct voltage in these spots or not?
What else can I check?
I'm going to swap the orange ECU back on and if no luck I'll install the previous MP distributor.
I'm starting to think maybe it's time to upgrade the ignition system and eliminate the ballast resistor completely.
I'm also thinking of getting an ignition system that will work good with a newer fuel injection system like FiTech....
Any suggestions? FBO, MSD?
Thanks.
Check the coil voltage within 30 seconds of switching on the ignition key. The ballast resistor will increase resistance quickly reducing coil voltage.
ground straps need to be big.
think I use 00 gauge, or something like that.
same with battery ground wire.
The easiest install IMO would be the FBO HRR688 ignition. It uses your original wiring harness and distributor plus you eliminate the ballast resistor. It's microprocessor controlled for improved operation.
http://www.4secondsflat.com/
Unless your battery is next to dead you need to check your resistances along the way.
Check the coil for resistance
Check the ballast for resistance
Any other surprise we don't know about
This will lead you to why you are seeing 3.5V when keyed on. Keyed on you should see 12V and when in run mode you should see 8-9V. You can switch to another system but why not fix this for a lot less $$$?
I wish I had more free time to tinker with the car but unfortunately we have a family member recovering from a stroke so my free time(and abilities) are limited.
I wanted to make sure it wasn't a fuel delivery issue so I borrowed an ignition run tool from my brother in law.
The tool connects to the car's battery and plugs directly into the coil wire input on top of the distributor cap.
This eliminates the car's entire ignition system and runs the engine off the box only.
With the box installed the car started and ran, the tool must eliminate the distributor advance as moving the distributor made no changes.
Previously the car would only run/idle for a couple minutes then would stall. The car would also stall when put in gear.
With the tool connected the car ran without stalling for over five minutes (and could have ran more) and the car didn't stall when put in gear.
I removed the dual ballast resistor and hope to have it checked tomorrow with an accurate meter as I don't trust my chepo multi meter.
I also removed the ECU, I'm not sure if the ECU would cause low voltage to the coil?
Any way to check the ECU?
I'll remove the Blaster 2 coil tomorrow and have it checked also.
Thanks
Quote from: HP_Cuda on October 02, 2017, 10:09:51 AM
Unless your battery is next to dead you need to check your resistances along the way.
Check the coil for resistance
Check the ballast for resistance
Any other surprise we don't know about
This will lead you to why you are seeing 3.5V when keyed on. Keyed on you should see 12V and when in run mode you should see 8-9V. You can switch to another system but why not fix this for a lot less $$$?
:iagree:
Quote:
"Previously the car would only run/idle for a couple minutes then would stall. The car would also stall when put in gear.
With the tool connected the car ran without stalling for over five minutes (and could have ran more) and the car didn't stall when put in gear."
That's good news, you are on the right path! The entire ignition system needs to be tested to find the problem. An accurate meter is required for proper diagnosis especially when trying to measure low resistance across the coil and ballast resistor.