GM 4pin HEI run problem..starts..but won't stay running

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rustytoolss

rustytoolss

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I've got a SB with a real GM 4pin module/ chrysler electronic distributor/ and a ford coil. The system has worked find for 3 years..up till now.
Back story. Moved my A100 last fall, everything fine. Went out few days later to move it again. Had a problem. Figured I would wait till spring/summer to fix it.
The engine will start. But as soon as I let go of the ign key, the engine will shut off (Just like a ballast resistor) Thing is I do not have a ballast resistor.
My system has the following parts Stock 1964 ignition switch, Bosh style relay, GM 4 pin module, mopar electronic didtributor (1973 style), and a ford resson coil.
Every time I let go of the key. The engine shuts off ! Just like a ballast ?????
Anyone out there with a GM HEI 4pin, that has had a problem like this. Please let me know what I should look for... Please.
 
Have never seen a GM ignition module act like that. I would test the ignition switch/connector/wiring first.
 
It is bound to be in the ignition power. How do you have the relay set up? Can you tell if it is working? Here is how just about all 12V Mopars, at least from "around" 63 or so up until lean burn season work:

You have ONE ignition "run" power in the engine bay, called "IGN1" It is hot ONLY IN RUN.........it goes COLD in "cranking" THIS IS PROBABLY the trouble

The second wire which IS hot during "start" is the coil bypass circuit. This is one usually brown wire known as IGN2. It goes from a separate dedicated contact on the ignition switch, to the coil + side of the ballast. THIS IS PROBABLY what is allowing the engine to fire

You need to determine where IGN1 and IGN2 come out of the bulkhead. Or, access the ignition switch and start there. Make certain that IGN1 is "hot" in the run postion. Check your relay, if it's powering the voltage regulator and ignition, you are probably triggering it from IGN1

See if the relay triggers, (should hear it) and see if it has power to the contacts, and then obviously, see when the key is on if power is going OUT
"Standard" relay diagram if you use the larger size:

best-wiring-diagram-for-a-5-pin-relay-simple-5-pin-relay-diagram-dsmtuners.jpg


30 should be full time power coming TO the relay contacts through a fuse or breaker. Make sure this is hot at all times. Typically, you might feed this off the large stud on the starter relay

87 is the controlled load. This should be what feeds power TO your ignition, voltage regulator, etc

85 is normally ground. Make certain it is so. This is also a good way to add a series unobtrusive switch, for theft protection

86 is the trigger voltage to energize the relay. this normally (in this case) would come from the origininal "IGN1" coming out of the bulkhead. Key in run---relay is energized
 
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if its a automatic check the neutral safety switch
 
I had this set up on my Slant 6 for a while. Ran good.
My tach lead shorted to ground from a chafed wire. Killed everything.
Once fixed the 4 pin was never the same. Changed out the module and back in business.
I worked for GM as a tech back in the time frame when those were "new". The 4 pins were hard to beat as long as they stayed cool and had grease on the backside.
Wish I had more to offer.
SN: the grease was di-electric grease used to help dissipate module heat to the heat sink in the distributor. It also kept down corrosion those big HEI caps had a tendency to collect from hot / cold cycles.
Again, very few issues with the 4 pins. The 7 pins on the other hand were not so lucky at first.
Also, dont underestimate going back to basics.... If all your wires are good then you just may have a bad module. Als,o test your reluctor on the distributor.
The pick up unit could also be not giving a good / clear signal. I dont remember the ohm reading of the 2 wires from the distributor but it should fluctuate as you spin the distributor evenly with the ohm meter hooked to it (disconnected to from the system that is) Also check your coil. You should be running an HEI coil for that module. Ohm out the primary resistance and the secondary. Might be a bad coil (getting hot?)
Joe
 
Found the problem. The pigtail at the Igntion switch was very loose. Slid back somehow. I'm surprised it would even start.
This would have been very bad . Had I been driving down the road (possible wreck).
Going to try to crimp the wires in the pigtail to prevent this from happening again.
Thanks for all your help. :)
 
rustytoolss said:
Found the problem. The pigtail at the Igntion switch was very loose. Slid back somehow. I'm surprised it would even start.
This would have been very bad . Had I been driving down the road (possible wreck).
Going to try to crimp the wires in the pigtail to prevent this from happening again.
Thanks for all your help. :)
Click to expand...


EXCELLENT! Always go back to the basics... nice work.
 
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