• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Electronic ignition troubleshooting help

Is there a way I can test the components to see if they are compatible?

I've heard about fitment problems with the mini starters. Are they a direct swap?
 
Is there a way I can test the components to see if they are compatible?

I've heard about fitment problems with the mini starters. Are they a direct swap?

Regarding the testing of individual components.....difficult.....as each manufacturer has their own design and testing parameters and are usually very reluctant to share them, especially the end user, figuring the average user does not understand how things work other than price. Most, but not all car enthusiasts, are in search of more power, lower ET's, reliable operation. Unless you have the time, equipment, and $$$, to set up a testing program to make the determination you seek, use or try name brands.

Re the starter fitment issues, unless you have headers and over sized exhaust pipes, a mini starter SHOULD fit, BUT only you can make the determination, as a mini starter is approximately 30% smaller than the OEM Mopar starter and 5-8 pounds lighter.
BOB RENTON
 
So one is basically at the mercy of whoever they are buying ignition system components from, as to their compatibility. I tried to get components that were as close to stock as possible (yet still worked!).

Looks like I'm back where I started. A car that won't start and still not sure which component(s) is(are) failing. With the information that I've posted what's your best guess at this point?
 
So one is basically at the mercy of whoever they are buying ignition system components from, as to their compatibility. I tried to get components that were as close to stock as possible (yet still worked!).

Looks like I'm back where I started. A car that won't start and still not sure which component(s) is(are) failing. With the information that I've posted what's your best guess at this point?

IMO....
Slow charge the battery overnite, CONSIDER replacing the starter to see if the voltage variation improves over your origional posting numbers. If it does improve, recheck voltages when cranking and check for a spark at the coil. If no spark, try a new ECU or coil (check by substitution). It's possible that the pickup coil in the distributor is faulty. Again check by substitution if possible.....one piece at a time.
BOB RENTON
 
Like Bob said get the battery charged up , trickle charge overnight

Good thread on a mini starter if indeed it’s going bad
https://www.forbbodiesonly.com/mopa...stalled-on-440cu-works.211081/#post-911792781


Another thing you could try , take a jumper wire (If you have a jumper wire with alligator clips or) directly from the positive side of the battery and attach it to the positive side of the ignition coil , then crank over the engine with the ignition key and see if the engine will start this way

If it does start and run , keep it running then remove the jumper wire from the battery , and see if the engine will remain running or shut off

Let us know
 
Last edited:
I did put a trickle charge on the battery last night before today's tests. But I'll do it again for tomorrow. I also have a battery load tester and the battery is checking out OK in every respect. Will post back with the battery to coil + jumper wire results.
 
Did the battery to Coil + jumper wire test. No change. Engine is cranking slowly and no indication that it wants to start. I'm still getting a strong, regular, yellow spark from the high tension lead. So I guess I'll order a mini-starter?
 
Installed the mini-starter today and the car still does not start (although it cranks really good now).

Same condition as before. I'm getting a regular yellow spark at the high tension lead. 3.6.v at the coil with ignition ON and around 7.5v with it cranking. Using a jumper wire from battery to the Coil + did nothing to make the car even come close to wanting to start. If I feed some gas into the carb while cranking it might cough a little but still won't start. The timing is probably way off now since I've been fiddling with it trying to get this thing started. Right now it's approximately at where it was on the day it actually did start. One other thing I'll mention if it makes a difference. On the day I did get it running a few weeks ago, I let it high idle for 20 min for the initial break in. When I turned it off there was a single muffled backfire through the tailpipe. Could that have anything to do with the current starting problem?

I am at my wits end on this. Ready to put an ad on Craigslist.
 
With the jumper wire connected to the battery and positive side of the coil is your high tension lead wire still producing a yellow spark when cranking over the engine ?

If it is , I would be looking at a new coil

Are you using a push button start button connected to the starter relay while cranking over the engine and turning the distributor - Just curious

With such a weak spark you might have gas fouled the spark plugs by now also

Man if you where close by , anyways

Hopefully someone can give you hand
 
Yellow spark is not what we want. Blue/white and crisp is what you're lookin for.
 
I'm about 50 mi. southeast of Tucson.

I used a remote switch to check for spark, and the ignition switch to check for cranking voltage.

I don't think I checked the spark with the bat-to-coil jumper wire attached. I'll do that to see if the spark quality changes. In the meantime I'll clean up the plugs and buy a new coil, and try again in a couple days.
 
Update...

Installed a new coil from NAPA. Removed and cleaned the plugs. There was just a light coating of black soot. While they were out checked the gap. Put everything back and tried to start it. No luck. Cranking voltage readings were the same as before. Same yellow spark as before. Jumper wire wouldn't start it either. If I fiddle with the timing I might get it to cough now and then. I noticed gas being expelled upward out of the carburetor while cranking so I figured it was flooded and let it dry out a while.

Came back a couple hours later and messed with it some more. Through lots of cranking and pouring gas down the carburetor it actually managed to start up. I was able to keep it going for a few minutes, during which time it ran VERY rough. It finally died and I couldn't get it started again. After it died, white smoke seeped out of the carburetor. At this point the engine wouldn't turn over very well so I have the battery on a trickle charge again to get ready for the next round.

So the car will start, but it obviously has serious issues. Is the spark too weak? Is this a carburetion issue? Is the low cranking voltage an indication there is an electrical problem somewhere else in the system? Just trying to figure out which is the next part I should throw a $100 bill at.

Thanks
 
I helped a member here with a 440 that ran very rough.
New Autolite plugs, 4 of which were not firing.
So once again, can't trust new parts just because they are new.
It actually started pretty well on 4 cylinders.
You've got to get the yellow spark issue worked out.
 
Just an FYI you can get an ECU for cheap from Mancini
upload_2021-2-9_15-47-45.png
 
After all the recommended checks for wiring, pickup coil, ballast resistor, voltages and reluctor gap etc...
Rather than cranking the engine all the time I would mark the rotor position, take a picture or something and pull the distributor.
Set up a spark plug with a jumper cable to a solid ground even the battery.
Start testing by twisting the shaft and note spark.
Do the run position testing first since you can do this by yourself then verify cranking spark.
Just some suggestions.
 
Just an FYI you can get an ECU for cheap from Mancini
View attachment 1066938
Be careful.....modules at this price are LIKELY made in China. Not saying that these modules are bad but some of these modules have a fake transistor on the outside of the case. IF you are contemplating a new ECU or module, consider the one from Rich Ehrenberg's web site... www.moparaction.net. or. 9400109898642630286773 on his eBay site.
From his site:
For Mopar:High-Performance HiRev 7500 ECUOutperforms MP "chrome box"High-performance hot-spark hi-rev-capable ignition ECU control module for all '72-'80 Mopar cars and trucks - Dodge, Plymouth, Chrysler - with OEM electronic ignition. Also fits all earlier Mopars that have been converted to the factory (MP) system (using stock-type coil and ballast resistor).
Bolt-in for all 4-pin and 5-pin ECUs with NO modifications, 100% plug and play. Works with 4-pin or 2-pin ballast resistors, again with NO modification. Made by an original Mopar / Chrysler vendor, but with latest all-silicon "computer chip" technology. Comparable to the MP "chrome box", better than "orange box", yet it looks so similar to the OEM stock unit, for that "stealth" appearance!
THE MOST RELIABLE ECU MONEY CAN BUY!

Perhaps you should call or e-mail him.....remember.....price should not be the only consideration....
Just my opinion of course.
BOB RENTON
 
After all the recommended checks for wiring, pickup coil, ballast resistor, voltages and reluctor gap etc...
Rather than cranking the engine all the time I would mark the rotor position, take a picture or something and pull the distributor.
Set up a spark plug with a jumper cable to a solid ground even the battery.
Start testing by twisting the shaft and note spark.
Do the run position testing first since you can do this by yourself then verify cranking spark.
Just some suggestions.

It sounds like you're describing bench testing the distributor. But I don't follow how everything is set up for this test.
 
Be careful.....modules at this price are LIKELY made in China. Not saying that these modules are bad but some of these modules have a fake transistor on the outside of the case. IF you are contemplating a new ECU or module, consider the one from Rich Ehrenberg's web site... www.moparaction.net. or. 9400109898642630286773 on his eBay site.
From his site:
For Mopar:High-Performance HiRev 7500 ECUOutperforms MP "chrome box"High-performance hot-spark hi-rev-capable ignition ECU control module for all '72-'80 Mopar cars and trucks - Dodge, Plymouth, Chrysler - with OEM electronic ignition. Also fits all earlier Mopars that have been converted to the factory (MP) system (using stock-type coil and ballast resistor).
Bolt-in for all 4-pin and 5-pin ECUs with NO modifications, 100% plug and play. Works with 4-pin or 2-pin ballast resistors, again with NO modification. Made by an original Mopar / Chrysler vendor, but with latest all-silicon "computer chip" technology. Comparable to the MP "chrome box", better than "orange box", yet it looks so similar to the OEM stock unit, for that "stealth" appearance!
THE MOST RELIABLE ECU MONEY CAN BUY!

Perhaps you should call or e-mail him.....remember.....price should not be the only consideration....
Just my opinion of course.
BOB RENTON

I'm certainly willing to spend the money if it guarantees me a working part But I was under the impression that all modern ECUs were made in China.

When looking at the product on his site I noticed something interesting. The instructions for the ECU said that bypassing the ballast resistor will destroy the ECU in a short time. Is it possible I fried my ECU doing the jumper wire test?
 
Auto Transport Service
Back
Top