I have a 97 Blazer 4.3 "W" Vin. First off, I'm pretty sure my ignition switch is going out because the dash lights will not come on sometimes, so the vehicle will not start. I can wiggle the key around and get the lights to come on and the vehicle will start. But that's not my problem... or is it my problem?

3 weeks ago I had the car running and didn't realize that it was my ignition switch making the dash lights not come on. So, I had a mechanic come by and he told me it could be my pick-up coil in my distributor (CAM Sensor). So I changed it, but still had the same problem. (I'm now assuming that is the ignition switch after browsing this great forum).

Well, I left it in front of my buddy' house during the week and someone popped the hood and stole my PCM. Needless to say I was ticked off and went to my local junkyard and got a computer from a cash for clunkers vehicle. Since then it sounds like the timing is off, and the snap-on scanner is telling me it is my CAM Sensor. Well, I replaced the CAM sensor again tonight and it is still not running right.

Could I have a faulty computer? The scanner didn't say that it was faulty but I'm not sure anymore. I noticed my coil wire going from the coil pack to the distributor has a white spot in the middle. Could this be bad and causing my problems? Has anyone else experienced the scanner saying it was the CAM sensor and it was something else? The computer was "flashed" and that didn't do anything either.

Any help, thoughts, or words of encouragement would be grateful. I have had this Blazer for about 2 years and have never had a problem anything like this before. I now have not been able to drive it since the beginning of September, and this is my only vehicle. I really like this car and do not want to get rid of it, but if I can't figure this out I will have no choice. Please help me if you can!

Tim

 

you will have to do a case relearn procedure so the PCM can learn the CKP/CMP tolerances for your vehicle, only a tech ll scanner is capable of this, I am sure if you take it to a dealer near you they can do it for you, just tell them that you got a different PCM from another vehicle and the CKP/CMP values need to be updated for your engine

 

Have you replaced the ignition switch yet?

If you replace the CKP (crankshaft position), CMP (camshaft position), and/or the PCM, you need to do a CASE relearn as Nvidia78 stated. Most full feature scan tools are capable of doing this procedure so you are not locked into going to the dealership.

Replacing the PCM with a junker is iffy at best. The PCM needs to be programmed to your VIN to work properly. This will update the PCM with the particular RPO codes present in your truck.

 

No I have not replaced the ignition switch yet. I figured it wouldn't affect the way the engine runs. Or am I wrong about that?

The first PCM I got from the junk yard was re-programmed for my car. He punched in the VIN number and everything. It still didn't run right and said it was still the CAM sensor. So I replaced the CAM sensor last night, and still the same thing. I just got back from getting another PCM from the junk yard. We replaced it and still the same thing (though I just learned that it needs to b programmed to my car), and then it just died. Now it won't start at all. I guess because the PCM hasn't been re-programmed yet.

My mechanic friend should be over here in the next hour or two, so I will get him to re-progam this new one I just got, and see what happens. If anyone can think of something else this might be besides a faulty computer please let me know. Or if my faulty ignition switch would affect the performance of my engine.

Very Much Appreciated,
Tim

 

A faulty ignition switch can cause a host of issues. If one of the contacts inside the switch is not allowing full power through it, it can cause some very weird things indeed. Since you are having problems with the dash lights, I would say that your ignition switch is on the way out.

 

I would replace your ignition switch and then go from there, like Swartlkk said it can cause some weird things to happen, it may not be getting full voltage to the ignition side of the switch causing it to not run.... I missed that you were having problems with your dash lights not coming on in your first post and skipped to your other problem you had with the PCM

 

I just wanted to let everyone know that I figured it out. When someone stole my computer, I was left with the task of replacing one of the clips. They just ripped the clip out of the PCM and ruined it. I had to cut the wires and put them back together. Well, I had the ylw/blk's crossed and that was the issue. I put them back together the proper way, and it ran like it did before!

Thanks for your input with everything. I really appreciate the help. Saturday morning the ignition switch will be installed. I read your right up about the ignition switch swartlkk, obviously I need to replace this ASAP.

Thanks again,
Tim

 

Glad you got it running good again

 

Good deal! Glad you got it figured out!