No Spark on EDI 5.7L 1996 Chevy Silverado

[bergerandfries]

So I've looked in Chilton's and Haynes books on troubleshooting this problem:

 

Starting about 1 month ago, my truck had hard starting. About 2 weeks ago I changed the sparkplugs, sparkplug wires, distributor cap and rotor. A week ago, hard starting again and checked the battery. Marginal. Exchanged the battery core for a new one. One start OK. Next start, no spark.

 

I've checked the output of the ignition coil with a spark tester and no spark. I've checked the ignition coil with an ohm-meter per the manuals and it checks fine. I've replaced the ignition coil driver module (my buddy had an extra) and checked the input to the driver from the battery and computer. All check fine. The manuals mention to check the Camshaft and Crankshaft postion sensors that feed the computer, so that's next. Any other suggestions out there?

[bergerandfries]

So the camshaft and crankshaft sensors check out fine. Buehler? Anyone? Buehler?

 

I took the coil off and plan on replacing it anyway. If that doesn't fix it, I'm taking it to a dealer and having a beer

[bergerandfries]

Forgot to add that no codes appear in the computer to indicate the problem...

[chevroletmb]

might sound far fetched but make sure the distributor is turning

[Rudy]

Check the pick up coil in the dist.

 

do you have an injecter pulse?

 

 

Rudy

[budhayes3]

What Year, Model, and Engine vehicle?

I had a similar problem with my 85 Monte SS, completely different, but many of the same designs and principles...turned out to be a bad ECM (or PCM as they are now called). There was a connector to the distributor with 4 wires that came from the ECM, with that connector unplugged, the car would run. This was a feedback carburetor though, no cam and crank sensors.

When you turn the key to on, is there a check engine lt? If not, the problem may be internal in the ECM. Hope this helps.

[bergerandfries]

What Year, Model, and Engine vehicle?

I had a similar problem with my 85 Monte SS, completely different, but many of the same designs and principles...turned out to be a bad ECM (or PCM as they are now called). There was a connector to the distributor with 4 wires that came from the ECM, with that connector unplugged, the car would run. This was a feedback carburetor though, no cam and crank sensors.

When you turn the key to on, is there a check engine lt? If not, the problem may be internal in the ECM. Hope this helps.

 

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1996 Chevy Silverado 5.7L Engine Code R, and there are no codes or check engine lights. Kinda what I thought if it isn't the coil then it must be the ECM, yuck.

[bergerandfries]

Well, new coil and still nothing. Crap.

[lowflyer]

Its real hard to diag. a no-start condition without having the vehicle in front of me, but here goes anyway:

 

Check the ECM1 fuse in the underhood fuse box.

 

With the key on:

 

Do you have system voltage at Terminal A of the Ignition Control Module (Pink wire) with connector off?

NO-fix wire from Fuse box to connector.

 

Do you have system voltage at Terminal A of the Ignition coil (Pink wire) with connector off?

No- fix wire from Fuse box to connector.

 

Do you have system voltage at Terminal D of ICM (Wht/Blk wire)

No-fix wire from ICM Terminal D to Coil Terminal C.

 

Do you have system voltage at Crankshaft position sensor Terminal A (Pink wire) with connector off.

No- fix wire from Fuse box to connector.

 

Check Resistance of Terminal C at ICM (Blk/Wht wire) to ground with connector off.

High resistance/open wire -fix wire to ground.

 

Disconnect VCM Grey connector and ICM connector. Check for continuity between VCM terminal 9 (Wht wire) and ICM terminal B.

If open, fix wire.

If not open - Looking at possible faulty VCM.

 

Try this and get back to us. Good luck.

[bergerandfries]

Well, the story is that the TERMINAL on the WIRING HARNESS was bad. It wouldn't make contact with the coil, so although everything checked out, when plugged together it wouldn't carry the electricity to the coil...