Trying to Stay Cool - FIXED!!!!

[dodj]

If it drops to 8v as soon as the fans turn on,  there is either something really wrong with your fans,  or there is something wrong with the wiring.  A battery won't drop to 8v instantly. Wire the fans directly to your battery with nothing else connected and see what happens.

[Cudajason]

Thanks @dodj

I did some more testing today.

I charged up the battery and my smart charger said it was fully charged.

Car fired right up.

Alt showed more than12 volts at idle, but never more then that.

I turned the fans on manually, all seemed fine.

Once everything warmed up the volts had dropped a little at the gauge, so stupid me went out for a spin.

It lasted a short distance before the volts dropped to 8 and the car would not take any throttle or rev under load.

Limped back home and tested again

The alt was reading 8 volts at idle measured at the alt post and grounded to the alt casing.

No change if I grounded to the battery or the engine ground.

I think, but I could be wrong that indicates the Alt is not up to task of the additional load of the fans

Other factors to keep in mind, I fried a battery last year as the wiring to volt reg went bad. Fixed that.

Have changed ignition boxes. Everything worked fine the last trip out, right up to the point it over heated.

So I think my next step is a new alt?????

[dodj]

So the fans are fine.
While in park, if you bring the engine speed up a bit does the alt charge at around 14v? Ebody electrical systems are famous for low alt output at idle.
The speed of the system going to 8v is a key symptom imo. Bringing a FLA battery down to 8v a few times will kill it. Try grounding the alt field to see if it goes full voltage. Or, bring it in to a shop to get it tested if you prefer. Perhaps the alt is bad but it may be the vr. Plus, you were messing with the vr a few months ago. I prefer to get as much info as possible before buying more parts. You have the alt, battery, vr and wiring. Two of them are rather expensive to buy.
Do you have another battery to sub in for a trip around the block? What dmod said about a shorting/compromised battery fits. And if you have brought it down to 8v a few times......

[Dmod1974]

Yeah, I'm still voting on an intermittent battery failure or loose/poor main power/ground connection.  Chassis, block, alternator, starter, battery, starter relay - something.

To put this in perspective - I'm running a Lincoln MK8 fan that has an in rush current draw of around 100 amps, and a constant draw of around 40 amps and I tested it with an old car battery that had sat on a trickle charger for 3 years and voltage never dipped below 10.5v after a couple of minutes of run time.

[Cudajason]

I had the battery checked out and they say it's all good...but with parts store employees these days you can never be fully sure!  They did "test" it useing a hand held device right in front of me...so 

It is one year old Canadian Tire / Mastercraft AGM battery.


I checked all the connection, everything is tight.  the MAD Electrical bypass is completed as instructed.

At this point, given the everything was working fine before the fan install, and the voltage only drops when the fans kick on, I am thinking that the alternator is the issue.  I think I am going to order a new Tuff Stuff 130 Amp alternator.

https://www.summitracing.com/parts/tff-9509resp

[Brads70]

Same price? I've had them on my cars for over 10 years now with no issues? These do actually charge at idle, unlike mopar alternators sometime struggle doing this?
I also have a spare I could lend you to try if you want? I have the same alternator on both the Challenger and the Javelin, and one spare.
https://www.qualitypowerauto.com/catalog.php?item=557

[dodj]

Before you buy an alt, test the one you have. Ground the field wire. Observe o/p.
As for connections...did you take them apart and check them for good electrical contact, or just wiggle them and figure tight is good? VR body ground visually clean? If the VR body ground has resistance, your alt will not work well.
I would try Brad's spare first before buying.... cuz I don't think it is your alt. Dropping fast from full charge to 8v doesn't fit a bad alt imo.

[dodj]

 

Not trying to rush you...maybe I am.....but interested in what the root cause of your problem is here.
I'm getting fat on the popcorn.

[Cudajason]

Not trying to rush you...maybe I am.....but interested in what the root cause of your problem is here.
I'm getting fat on the popcorn.

LOL, sorry to keep you waiting.

Unfortunately I have not had time to look at the car again.

I did just visually inspect the wires and connections.  everything was tight with the exception of the field wires on the back of the ATL. they were a little lose.

I will try to get some time on it this week, if not the weekend.

I may also pull the electric fans off and run the clutch fan and see what happens.

The part the confuses me is that the only thing that has changed is the rad and electric fans.  The car ran great before that.  The issue only shows up when the fans are on.  That is why I am leaning towards the Alt not being able to keep up with the fans.

[Blowout]

@Cudajason how was the wiring set up for the fan relays?  Was it plug and play or did you have to do that part yourself?  Where are you drawing power for the relays?

[Cudajason]

@Cudajason how was the wiring set up for the fan relays?  Was it plug and play or did you have to do that part yourself?  Where are you drawing power for the relays?

@Blowout

I have done the MAD Electrical bypass long ago.  The main wire runs to the starter solenoid.  I have a lead the runs from the starter solenoid to a distribution block that I pull power from. 

The main power to the Fan Relay is pulled from that Distibution block.  The ignition / ACC Power for the relay is pulled from the ACC terminal on the fuse block.

[YellowThumper]

I recommend taking up offer and test the new alt.
Least amount of work for a simple test to new sure.

[Cudajason]

Oh man, i thought I had it all figured out tonight.

Took the electric fans off and put my clutch fan back on, car ran great. Its a cool night but out on the road the temp gage never went above 180.  Did not go too far, but usually it would
Be over 200 in that span. Car ran great. Volts just a little over 12, right where they always are.

Idling in the driveway, she creeped up to 200. Out for a quick spin, right back to 180!  That never happens. I was very happy.  Then I noticed the volts, reading 10 and dropping. damit!  Back home just as it started running rough.

So clearly something is not right.

I am concerned that I never see more than 12 volts.

Clearly something is not right. I guess its time to check some connections.

I am excited that the rad seems to have helped my overheating issue. Now on to the electrical issue.

I will also do a separate post in the electrical section.

[Cudajason]

Ok, just to update this thread.

I have installed a new 30 amp alternator due to the charging issues I was seeing.  I used a 1 wire alt and took out the factory VR.  Seems to work now.  Took the beast for a spin over the weekend, with the electric fans installed. The old girl ran great, no issue with the charging system once the fans kicked on.

More importantly, on a pretty warm day, the car never went above 190 / 200. the combo of the aluminum rad and dual Spal electric fans works!

I think I have finally solved my cooling issues.  Next up a longer drive including some highway time!   

[YellowThumper]

Ok, just to update this thread.

I have installed a new 30 amp alternator due to the charging issues I was seeing.  I used a 1 wire alt and took out the factory VR.  Seems to work now.  Took the beast for a spin over the weekend, with the electric fans installed. The old girl ran great, no issue with the charging system once the fans kicked on.

More importantly, on a pretty warm day, the car never went above 190 / 200. the combo of the aluminum rad and dual Spal electric fans works!

I think I have finally solved my cooling issues.  Next up a longer drive including some highway time!   

AWESOME!  and better yet, you still have summer left to enjoy it.
Now be sure to add an anode in your system. Drain plug is an easy place.
Not sure if you have this available but it is what I use in mine and see virtually zero electrolysis.
Using Prestone I had an almost immediate electrolysis visual.