Mechanics

IGNITION CONTROL MODULE

1998 Pontiac Transport

Electrical problem
1998 Pontiac Transport 6 cyl Front Wheel Drive Automatic

Ok what happened here is me and my dad decided to pull the alternator as it was giving him problems. If you worked on this truck you know it's a pain in the butt to get out.
So we decided might as well do the cables and plugs since we'r removing the intake manifold will be able to get to the back ones. We finally get done mounting everything to discover the the labels on the cables came loose so after about 30 minutes I found the correct firing order plugged the cables in turned the car on it turned on but it shakes like when one of your plugs is bad.

so I decided to check today thinking my dad might have left one of the rear cables loose to one plugs but no go.
I started checking the Ignition control module just find that the number two cylinder plug is firing a really weak spark but the rest of them fire normally.
My question is. Is this a bad ICM or could this be caused by somthing else?
Thanks
Avatar
Raptorms
April 12, 2010.



Try swapping coil packs to see if miss travels to another cylinder.

Tiny
Tooomanytoys
Apr 12, 2010.
Thanks il try it.
I meant Coil packs not Ignition control module sorry for the confusion

Tiny
Raptorms
Apr 12, 2010.
Okay i tried swapping coils and the problem does not move with the coil it stays on the same cylinder so this rules out a problem with the coils. still is there anyway to know wheater my ignition module is at fault because i dont want to replace it without it being sure it cost's roughly 90$ (alot of dough right now)

I also re did my test to check there is a spark but far weaker then the others, when i unplug the cylinder there is no arc to the coil but when i do it to the others there is. aside from seeing the diference i felt the difrence between the sparks on my arm lol

Could this be caused by the wires coming from the powertrain control module (as i no longer trust connectors on this truck) or would one of those wires being loose just cause it to not work at all


http://www.2carpros.com/forum/automotive_pictures/516029_1998201999203_8L20Engine20Schematic_1.jpg


Tiny
Raptorms
Apr 12, 2010.
Here is the schematic bigger just open the link
<< http://farm5.static.flickr.com/4015/4516595106_f72a48b47a_b.jpg >>

Tiny
Raptorms
Apr 12, 2010.
It could be the module. However because it happened when you were changing the plugs and wires. I would look more into what could have caused it. Maybe the spark plug wire has an internal open. It would help to put a scanner on it to see the misfire graph.

Tiny
Tooomanytoys
Apr 13, 2010.
Well I don't think it's the spark plug cables as they are new and also I have been looking for spark at coils not cable ends.

And what machine are you talking about to analyze the for misfires exactly (obd2)? (I have no check engine light) or any light their all off

Oh so the ignition Module is good I got it tested at autozone

I guess im at block one again il try swapping coils again just to make sure.

This is becoming a pain in the butt (now im stuck riding two wheels while my dad enjoys my comfty seat and sound system lol)

Tiny
Raptorms
Apr 13, 2010.
Yes. You need to hook a scanner up with misfire data capabilities to the obd2 connector. Most accurate would be a tech2 from g.M dealer. This will help you see the counts in a graph to see when miss occurs. The check engine light does not always set if the miss is minor or intermittent.

Tiny
Tooomanytoys
Apr 14, 2010.