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Old 02-07-2022, 12:37 PM   #1
edflores
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Join Date: Jul 2005
Location: Riverside CA
Posts: 860
1987 TBI K5 No spark

I Bought a 87 k5 350 tbi. Was running at a very high idle ( 2200-2700rpm). Previous owner put on a rebuilt TB. Checked everywhere for vacuum leaks. Found one at the TB base.Still high Idle. Performed TPS relearn. Idle dropped significantly but still a bit high.
Test drive and it dies as soon as you put it in gear. Would sometimes struggle even if you kept it alive, sometime ran like a beast.

I decide to do a tune up. I was advised to do a new distributor.
Replaced distributor, Coil, plugs and wires.
No Spark.
I have replaced ignition modules. Nada
Another new coil. Nothing.
Whole distributor again. Nothing.
I did the test on GM manual and I keep getting bad coil or module.

Injectors are firing while cranking so pickup/ecm seems good.

Only other thing that caught my eye was my dash volt gauge reads low most of the time. like 8 volts. Even if It gets to 12, it drops down very low while cranking.
I still have 12v at the coil though

Any thoughts or ideas?
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Old 02-07-2022, 10:02 PM   #2
Pano
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Location: MA
Posts: 116
Re: 1987 TBI K5 No spark

I have an 87 GMC with a 350 TBI. Several years ago it just died and had no spark. I replaced the distributor, rotor, coils and a few other things.

Finally I replaced what I think I remember is the ignition control module. It is near the distributor, under it or in it. It is small and has a 2 wire connector. Started right up.

Sorry, just reread your post and saw you replaced the ignition module. I do think the 2 wire plug needs to be oriented correctly for it to work. I don’t remember if it was keyed, but worth a look.

Last edited by Pano; 02-07-2022 at 10:10 PM.
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Old 02-08-2022, 07:58 PM   #3
Just call me Sean
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Posts: 1,598
Re: 1987 TBI K5 No spark

Did you try putting the old distributor back in?
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