1988 - 1998 (GMT400) Section for all discussion related to the 1987-1998 Chevrolet and GMC trucks.

1998 k3500 cranks but no spark headache

Old Sep 11, 2019 | 12:56 PM
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Default 1998 k3500 cranks but no spark headache

I have a 1998 Chevy K3500 with 7.4l engine. Truck will crank over but am getting no spark. For a littel background, this problem started immediately after I had a hard time getting starter to crank over ( this ended up being due to a bad grounCd strap). Had stopped at a place to pick something up, came back out and tried to start truck. Starter was having a hard time turning over. Found out this was due to ground cable near starter being connected by only a few strands. Replaced that and starter turned over like before, but truck wouldn't start.

Checked coil and was not getting any spark from it.

Checked for signal coming from computer (Power Control Module) to Ignition Control Module and that seemed good. Hooked DVOM to ground and signal wire and got about 4.0 V. Shop manual says should be 1 - 4 volts.

Ground and Power to ICM check out o.k., but not getting any signal from ICM to coil. Replaced with new ICM, no change. Thought maybe I got a bad ICM so put another new one in. SAME #@$%# RESULTS!!!

So what to do?
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Old Sep 11, 2019 | 1:11 PM
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Could I have got two bad ICM's in a row? Am I frying the ICM's somehow?

The ICM's are BWD from Advance Auto.

When I had problems with the starter the gournd/neg. battery coil got very very hot. Wondering if I did damage to some wires some where else.
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Old Sep 11, 2019 | 3:47 PM
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I'd say check the ground with the ground side of your vom clamped to the ground side of the icm.
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Old Sep 11, 2019 | 10:08 PM
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I already tried that. Compared ground wire to battery (+) post, reads battery voltage. Compared to battery (-) post, reads 0.0V. Also tested ground with a head light as a test light.
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