440 engine grounding with aluminum heads

[GrandpaKevin]

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.

[734406PK]

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.

[GrandpaKevin]

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.

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.

[734406PK]

Check the coil voltage within 30 seconds of switching on the ignition key. The ballast resistor will increase resistance quickly reducing coil voltage.

[cudabob496]

ground straps need to be big.
think I use 00 gauge, or something like that.
same with battery ground wire.

[734406PK]

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/

[HP_Cuda]

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 $$$?

[GrandpaKevin]

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

[734406PK]

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 $$$?

[734406PK]

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.