No spark on passenger side of engine

SHANENEALE

MEMBER
1999 GMC SIERRA
208,000 MILES

I have a 1999 gmc seirra 1500 4x4 with the 4.8 in it. I get spark on my driverside but I dont get any spark on my passenger side. I reasontly changed the intake manifold on it I dont know if that would have anything to do with it. I had to take off my wiring harnest to change it but I pluged evry thing back in.

10 Replies

SATURNTECH9

MECHANIC
30,869 POSTS

So are you missing the power side to the coil or ground pulse to the coil?

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Thursday, October 24th, 2013 AT 3:37 PM

SHANENEALE

MEMBER
4 POSTS

No I dident mess with that side of the coil packs when I changed it plus two on that side are brand new

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Saturday, October 26th, 2013 AT 8:16 AM

SHANENEALE

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4 POSTS

Yes

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Saturday, October 26th, 2013 AT 9:44 AM

SATURNTECH9

MECHANIC
30,869 POSTS

Alright with a test light with the key in the run position pin D on the connector going to the coil should have power to it on all four of the connectors. Also Pin C on the connector should have a flashing ground while cranking. Pin A to the connector should have a constant ground to it.

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Saturday, October 26th, 2013 AT 5:03 PM

DM AUTO

MEMBER
2 POSTS

No ground pulse.

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Thursday, May 3rd, 2018 AT 4:00 PM

DM AUTO

MEMBER
2 POSTS

Did your test everything but ground pulsing?

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Thursday, May 3rd, 2018 AT 4:00 PM

KEN L

MASTER CERTIFIED MECHANIC
47,513 POSTS

This sounds like you lost the coil drivers inside the PCM which means it needs to be replaced. Here is the location.

You may be able to get a used one and plug it in to confirm the issue.

Check out the diagrams (below).

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

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