2002 Alero - ignition control module?
 

Hi, all,

This is my first post, and am hoping to get some good advice here! I have owned my 2002 Alero for 7.5 years now. I'm encountering my first real engine trouble with it. In early December 2014, it started to have some trouble getting up to speed. In February and December of 2013, I'd had to replace the coil pack (both used), and figured it was the same issue. Instead of going used, I bought a new one and replaced, only to have the same problem persist; however, at this point, the engine would start and idle no problem, but as soon as put into gear, it would sputter out.

Before replacing the coil pack, I used the diagnostic tool to find it was giving the following errors:

OBD-II Trouble Code: P0301 Cylinder 1 One Misfire Detected

OBD-II Trouble Code: P0172 System Too Rich (Bank 1)

OBD-II Trouble Code: P0141 Oxygen O2 Sensor Heater Circuit Malfunction (Bank1, Sensor2)

Because of the one on cylinder 1 misfiring, I tried the brand-new coil pack. When that didn't work, I tested the spark plugs and all four were getting a spark. Next I thought it might be the fuel injectors or the timing chain or even head gasket. After testing the fuel injectors by listening to them with a stethoscope and testing for power, I think they are fine.

Next, I tried swapping out the ignition control module (ICM), by using the two old ICMs from the original and first used coil pack. Before trying this, the car was starting, idling, and sputtering when tried to put into gear. Each of the old ICMs didn't even get the engine to turn over, and then putting the existing ICM back on gave the same results (although it got closer to turning over). :confused:

Any advice on if a new ICM would potentially solve this problem? or is there something else I'm overlooking? I don't have a lot of money, so am trying to get this fixed in my laneway and don't want to have to pay to have it towed to a mechanic to find it'll be $1000+ to fix whatever is wrong.

Any direction would be greatly appreciated!

Well, nobody on here was of any help... for anyone else who might be seeing problems like this, here's what happened: I ended up not driving the car for a couple of months until winter had passed. When I was able to drive it two blocks to the mechanic, it turns out the catalytic converter was completely clogged. Replaced with a new one, the car was back in business.

Glad you got it resolved. Doubt many would suggest the CAT being the problem. I am having similar probs with a non-Oldsmobile vehicle. Am wondering if the CAT should be investigated?

Did you happen to notice a smell of rotten eggs/phosphorus when investigating this problem?

Well, we're going back a year and a half now... :p but to the best of my recollection, there wasn't any sulphur smell. I did have that once before when the ICM went once before from unevenly burning the fuel.

Best of luck finding the solution!