Ignition Control Module

[santacarl]

Hi All....

I'm thinking I have an ignition control module issue.....surges around 45 mph going up hills....

Here is the question..... Does the Ssei have use a different ICM than a base model? Is there a significant difference between the AC Delco module and the Delphi one? There a hundred bucks difference between them at Advance Auto..... I'm not into 'cheap' so I'll avoid their Borg Warner ICM....but since Delphi has been a GM supplier of electronics was just wondering if there is a hundred bucks worth of 'better' in the Delco one....

Thanks for any thoughts...

SC

[harofreak00]

Same ICM between all models.

I sell good used ones for much cheaper, PM me.

[Petermcmxii]

ICM just distributes spark to the coil packs which sends spark through the plug wires and to the plugs themselves. Surging going up hill sounds more of a throttle problem

[Ken_W]

Sounds like the somewhat-common chugging problem. Supposedly is a design issue in the tranmission controller's programming (assuming that your ignition system and vacuum lines are good); the car doesn't shift early enough when going up low-grade hills and winds up bogging down a bit.

I'd love for somebody to find a fix for this, but after getting into it last year (and replacing several parts) I could not make it stop doing this. Like many others who responded to my query and tried taking this on in the past, I now just live with it. If you tap the gas pedal when this happens, the car will usually downshift in response, and the surging/chugging stops for that instance. If you wish to pursue it further, I would suggest going back and reading the previous discussions here at the Club to get more insight. There was also a GM TSB on the topic, which basically said to make sure your ignition system and vacuum lines were up to code.

Ken_W

[harofreak00]

ICM just distributes spark to the coil packs which sends spark through the plug wires and to the plugs themselves. Surging going up hill sounds more of a throttle problem

Surging is probably the mostly commonly misdiagnosed problem we have here.

A bad ICM is a known problem for surging. A misfire can be attributed to many things including: plugs, wires, coils, ICM, injectors, MAF, etc.

I've never seen a surging problem from a bad TPS. Usually a bad TPS just causes incorrect idling or transmission shifts.

[santacarl]

If you tap the gas pedal when this happens, the car will usually downshift in response, and the surging/chugging stops for that instance. Ken_W

That nails it to a tee.....and after further testing....it only does it when in O/D......around 45mph with slight application of the accelerator pedal when going up a slight grade......

I also notice that it seems to diminish as the car gets warmed up......

I'm thinking the ICM may have been a premature thought on my part.....as I had run across it in another thread....but what you described is reproduceable in my car....precicely.....

So, does that condition cause any internal damage if left unchanged?

[santacarl]

ICM just distributes spark to the coil packs which sends spark through the plug wires and to the plugs themselves. Surging going up hill sounds more of a throttle problem

I thought about that and replaced the TPS a while back....no change....but I'm starting to center in on the TC when in O/D.....

[harofreak00]

Surging is probably the mostly commonly misdiagnosed problem we have here.

Get a scantool that can read misfires. I'm 99% sure you will find that you have a misfire problem.