Ignition problems 440

halifaxhops

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First place I would check is the bulkhead connector for corrosion/dirt or a pushed connector. Your getting there. Do you have a wiring diagram for the car? If not Mymopar has most of them online and you can print out it from there.
 

Big_John

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First place I would check is the bulkhead connector for corrosion/dirt or a pushed connector. Your getting there. Do you have a wiring diagram for the car? If not Mymopar has most of them online and you can print out it from there.
^This^
 

Big_John

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And I find this taped and I assume spliced in red wire at BR slightly troubling. What is it for?

20210625_180142-jpg.jpg
 

thethee

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First place I would check is the bulkhead connector for corrosion/dirt or a pushed connector. Your getting there. Do you have a wiring diagram for the car? If not Mymopar has most of them online and you can print out it from there.

Yes the full wiring diagrams are in my FSM, those have come in handy in several occasions. Will look at the bulkhead connector first, thanks.

Just to be sure but BR should get full battery voltage right?
 

68PK21 440.6bbl

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Red wire is indeed spliced in with additional inline fuse. It serves as power feed for my propane evaporator mixer. Not how I'd like it but was put in by PO. It's on the to do list.
I was waiting for someone to mention this, 50+ posts in before it was mentioned. I would've started right there first.

1975.IMP.Ballast.Wiring.jpg


Really, anywhere you see electrical tape where it doesn't belong and you didn't do it... welp that's the first thing I start too rip apart if there are electrical problems.

.
 

Big_John

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I was waiting for someone to mention this, 50+ posts in before it was mentioned. I would've started right there first.

View attachment 469096

Really, anywhere you see electrical tape where it doesn't belong and you didn't do it... welp that's the first thing I start too rip apart if there are electrical problems.

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With the close up, there's something else... The red wire goes to the top connector on one pic, the bottom on the other.

While that really doesn't make a difference, if that red wire is part of the issue, possibly causing an intermittent break in the green "jumper" wire, that could cause some even stranger readings where one side works this time, but after testing, suddenly it doesn't work. Know what I mean?

If this were mine, that red wire would move up the list to "do it now".
20210625_180142-jpg-jpg.jpg

1975-imp-ballast-wiring-jpg.jpg
 

68PK21 440.6bbl

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Yea he's flipped the connector around, and I know it's not his doing, with I take it the spliced in red wire has something to do with a propane conversion.
If the propane needs some kind of ignition on feed there are better places to tap into IMHO.
 

thethee

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Well... it's not the bulkhead connector. Some terminals are a bit corroded and I will definitely clean them up but with it completely disconnected the ignition system still has power. Will have to check with my FSM if that is normal or not.

About the red wire, it is removed for the time being. I hadn't even noticed but yes I did flip the connector on the BR.
 

thethee

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Well I quit monkeying around and I fixed it! :D

Spoiler alert: it was a faulty ECU

Okay so first thing I did was to pull entire wiring harness from the engine bay and mostly from under the dash. This might've been overkill but I knew it would keep bugging me if I didn't and it couldn't hurt to inspect the wiring anyway. Learned a lot from this. For instance, unlike prior years, my Imperial doesn't have a bulkhead connector but rather something they call a 'terminal block' located under the dash near driver door. Ignition system bypasses this completely. Also found several fusible links that I was unaware of. Inspected those and "they looked good" for how much one can tell from that.. Inspected my ignition switch and it was fine, luckily, since I already looked online for tilt/tele switches and those appear hard to find. With my multimeter also checked for continuity in ignition wires and they were good. Convinced it wasn't a wiring issue I cleaned all the connectors, reapplied electrical tape to the harnesses, and put it all back together.

For some reason it didn't want to fire at all anymore. Triple checked I connected everything back up correctly and it was so needed to look further.

So what I did next was
- check voltage everywhere and all checked out, plus side of coil was live
- performed all ignition checks on ECU connector as mentioned in the FSM
- pulled coil wire from distributor and moved near ground so I could see spark
- removed distributor from engine and spun over by hand, but this didn't produce sparks
- connected different distributor and spun it over but again no sparks
- checked both distributors for AC voltage output and both were well over 1 V
- disconnected distributor and grounded engine bay side of the connector, no spark
- ran a temporary wire from battery directly to plus side of coil and grounded the connector, but no spark
- swapped coil for old one but still no spark
- ran dedicated ground wire from ECU bolt directly to negative side of battery, same result no spark

By then I decided it had to be coil or ECU related so I got a new one of both through rockauto, they came today. First I plugged in the new coil and it didn't produce a spark. Wired in the new ECU and when I grounded the distributor connector I could see spark! Tapped it a couple times and each time gave a nice clean spark. Put it all back together only to have forgotten which way the distributor was when I first pulled it so on my SECOND try it fired right up. :p

I'm convinced that my previous intermittent problems were due to the ECU dying and by now it has actually died but will need some time to be 100% sure. Big thanks for all the help from all of you! Took me some time but I took advantage of having the dash out to also fix conversion from ATC to manual controls, will write that up in the coming days.

Again, many thanks!
 

NY69

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Congratulations on your victory; looking forward to your ATC adventures.
 
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