79 Fried Igniter (1 Viewer)

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Have spark and igniter works! I ended up doing a continuity test to match the connectors to the coil terminals using the old ignoter as a reference. It runs now, as good as it did before it stopped running.. I am not sure what the issue was, but I appriciate everyones help/feedback.
 
Here is what it looks like ready to go back in.
IMG_20200429_080758.jpg
 
Unfortunately I am back to square one. I am having the same no spark issues I was before I swapped to the newer igniter. The only situation which I could think of being consistent to the first time it fried was trying to turn the engine over with the spade connector unplugged from the starter. I highly doubt that could be the cause of not getting spark, but at this point I'm not ruling anything.

It ran normally for about 2 months only being moved around the shop only for a few minutes at a time, no long duration driving or trips. I ran when I needed to verify an exhaust leak after the manifolds and carb were pulled off for about a week. I installed the fuel tank, filler neck and hard lines and during this process it decided to stop giving me spark.

I pulled apart the igniter and nothing looked toasty, I checked continuity of all the spliced together connectors and lines, no problem. Made sure the ignitor was getting power, check power and resistance of the coil. pulled the distributor cap and nothing weird there. no fuses blown.

Seeing as the problem magically went away when I switched to the new igniter, im not sure the issue actually went away and I was just getting lucky for a small amount of time.

In any case does anyone have another idea to track down the problem and get reliable spark?
 
Is there a chance that during the process of de smogging that a sensor or plug got disconnected and that is what is causing no spark? Is there a handful of grounds that I should check to make sure no circuits are open?
 
Post up some pictures of the wiring setup you have. Did you follow the schematic? Your wiring harness has a built in resistor, are you sure your getting proper voltage?

@Coolerman

Haynes1979FJ40Page1.jpg
 
Thanks,I highlighted what I believe to be the isolated igniter wiring. I want to double check all fuses to start with. I am not sure about the resistor/condenser or what the values should be? I have read conflicting info about needing one but it should be about 1k ohm? What is the purpose of the cooler control box? can this be bypassed?

I would like to get a distributor to rule out a bad signal going to the igniter. I will just plug the igniter into it and spin it manually. Is there a preferred PN i can used to get something from oreilys/autozone that way I can just bring it back when I'm done.

I will get some up close pictures of the wiring later today.

Capture.JPG
 
I was able to check continuity of the 2 wire connector coming out of the igniter. It seemed fine going up under the dash till I traced one wire back to the ignition and the other I believe went into the carb cooling control box? I couldnt get the connector off so Im not 100% sure. It could have also gone into the emissions 'computer'. The single yellow wire also had continuity up under the dash until it went into one of the two above boxes.

I am still not sure what changed or got unplugged since it started and ran fine a week or so ago. I am pretty sure there is no resistor hooked up but again it started without it before??

I have one single bullet connector which isnt hooked up to anything. I know that if I ground it out the engine wont crank, and if left open it will turn over just fine.
IMG_20200727_174222.jpg



not the greatest wiring pictures but these are the two connectors coming from the igniter. a single yellow wire and a pair of black with yellow stripe wires.

IMG_20200727_174211.jpg

IMG_20200727_174206.jpg
 
Are there any components that can be easily bypassed to simplify the system?

I would like to fully remove the cooling control and emissions control boxes and take all the the associated wiring out of the harness as soon as I can isolate the problem.

soon after I get it running I will be swapping in a 2H so all of the wiring and ignition drama will be irrelevant but I still need to get it to the point of running and driving before that.
 
Distributor

Can I use this distributor as a way to verify the coil and igniter. As I have seen some mention you can hook up the distributor and spin it manually to get a spark.
 
Unhook as much as possible under the dash....meaning Emissions computer, cooling fan relay, seat belt warning buzzer.
Run a wire from battery to engine fuse wire temporarily to by pass the main power wire. See if it starts. Maybe could be a short somewhere in the main harness. Just do this as a test, not to run it.
The other option to get it to run is just go with a old points dizzy with coil.
 
Shark56 said:
Unhook as much as possible under the dash....meaning Emissions computer, cooling fan relay, seat belt warning buzzer.
Run a wire from battery to engine fuse wire temporarily to by pass the main power wire. See if it starts. Maybe could be a short somewhere in the main harness. Just do this as a test, not to run it.
The other option to get it to run is just go with a old points dizzy with coil.
Click to expand...

Ill try that, if no luck what is the 'preferred' (if there is such a thing) points distributor to swap in?
 
I have a 79, de-smoged and a gm igniter 115,000 mi. Changed plugs and then no spark. Tracked my issue down to the distributor pickup coil air gap. Distributor shaft bushings being worn meant i needed a tight air gap. your thread has reminded me I still need to rebuild my dissy. Might be your problem also ? Mike
 
I pulled the cap off the distributor to adjust the pickup gap. The gap looked fine but I shifted the pickup a bit closer. I dont have an oscilloscope to see the wave form but I checked with a multimeter set to read AC and I was getting .1-.3v while cranking. I think I can check the distributor off the suspect list since I think it is giving signal to igniter.

Next I am going to try to jump 12v directly to the engine fuse to bypass the wiring harness as per @Shark56 recommendation to see if that does anything. :meh:
 
At a loss now.

I unplugged various harness connectors and ran 12v directly to the engine fuse, verified the igniter was getting power while cranking and still no spark. I can recheck the internals in the igniter to make sure nothing was damaged while trouble shooting, otherwise I am out of ideas.

Anyone in san jose area want to come check out my wiring? :crybaby: Also if anyone is getting rid of an older points style ignition system I am interested...
 
When I converted mine 7-10 years ago the thread I used said it was important that the gm module have a proper heat sink or as you have described when running it for a longer period of time it would stop because the igniter got too hot and fried. I have this same igniter on a 82 toy truck 22r engine which is my daily driver and have had 0 issues with both vehicles(except when I had to run a tighter air gap because of a worn 2f dist). Could it be that your igniter has gotten too hot and fried?
 
456z said:
When I converted mine 7-10 years ago the thread I used said it was important that the gm module have a proper heat sink or as you have described when running it for a longer period of time it would stop because the igniter got too hot and fried. I have this same igniter on a 82 toy truck 22r engine which is my daily driver and have had 0 issues with both vehicles(except when I had to run a tighter air gap because of a worn 2f dist). Could it be that your igniter has gotten too hot and fried?
Click to expand...
Yeah I did notice that just with the ignition on, the coil was warm/hot, a lot more than I think it should have been just sitting there..
I will open it up again and verify the insides look okay.
 
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