My mother 1990 Lumina Sedan suddenly refused to.

DAG2012

MEMBER
1990 CHEVROLET LUMINA
120,000 MILES

My mother 1990 Lumina Sedan suddenly refused to start the after she had ridden it the day before without any issues for years. Last time it had a problem was when it suddenly died about 12 years ago and I believe the mechanic said it was the CPS (Crankshaft Pos Sensor). If I remember right he said he bypassed it so that it would never cause any future issues. And whatever he did worked well for years, I have a few questions, is bypassing the CPS possible? After trouble shooting this car now for the last 10 days, we eliminated fuses and such and to me it looked like it could be possibly the Ignition Control Module (ICM) or the Electronic Control Module (ECM/PCM). Took it in to a garage and after their analysis they said it was probably all 3. I said that's impossible for all 3 to die at the same time. So they convince me to replace the least expensive part, the CPS. If fact they said there are 2 CPS's in the Lumina one in the Oil Pan and one outside (I don't believe there is 2). Anyway silly me agreed to let them change the outside one which is the only one I am aware of. Needless to say once replaced the car still didnot start (still has no Spark at the coming of the Spark plugs). So now they thinking to replace the IGM, then next possibly the ECM. I am reluctant to give them the ok to replaced these in fear that the bill mounting up and there's no guarantee that after all 3 parts are replaced that the car will start. My initial thoughts was that the ICM had gone, only wished that they had started there first. Any opinions?

5 Replies

JDL

MECHANIC
16,098 POSTS

I'm not sure which lumina you have or the litre size of engine? If somebody has fooled with your wiring I don't how to help? Check applicable trouble codes. You can check mil codes, yourself. You have dis ignition, no distributor? Engine cranking, do you have injector pulse?

To check for mil codes, you use a jumper wire between the A & B terminals at the datalink connector, then turn key just till dash lites come on, no further, no crank. The mil starts flashing, you count the flashes to get the codes. Your looking for two digit codes.

Like I said, I don't know litre size of engine. Some of the info I looked at, I only saw one crank sensor?

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Thursday, November 22nd, 2012 AT 9:51 PM

DAG2012

MEMBER
4 POSTS

Sorry didn't provide you all the details initially.
The car is a 1990 Lumina Sedan 3.1L motor. Vin T. No one has fooled around with the wiring prior to it not starting. I did mentioned privously that 12 years ago the CPS was gone and the mechanic either repaired it then or I keep remember something to the effect that he bypassed it and it would never ever act up again. (Maybe I am not remembering that correctly, can a car run fine for 12 years with the CPS bypassed?). Anyway dealing with today problem, the car was checked for blown fuses, (none had blown). I had put in a new battery knowing that the old battery wasn't the problem, but the old battery that was in when the car now failed to old and a bit weak ) What I didn't know was whether this would affect the mil codes storage? A retired mechanic friend of ours has a diagnostic reader and it found no codes with it, nor did we see any by manually jumpering A to B, just gave us the intial 12 code only.

So I do have an update on the current garage statement. They now said that there is only 1 CPS, but that it broke off when trying to replace it and they have to drop the oil pan to get after it, Apparently this is a rather lengthy job as they quoted that the Mitchell Book states it take 3.5 hours of labour to replace it. Yipes the bill is getting huge, and CPS replacement probably is not going fix it. Garage Mechanic also said that oil had leaked into the sensor and that it most likely wasn't working properly (can't these be tested) so therefore there first item to repair was the CPS, then possibly the ICM. I would think that if there was oil affecting the CPS that some form of car performance degradation would have been noticed before the car completely failed. (That wasn't the case, car ran fine beforehand). Problem I have with that statement is I cannot believe 2 items failed at the same time. The car was running perfectly fine prior to this, so I would assume only 1 critical component failed and not 2 or 3 or more. Opinions?

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Friday, November 23rd, 2012 AT 12:56 AM

JDL

MECHANIC
16,098 POSTS

If you have fuel injector pulse, then there is an rpm signal. The rpm signal comes from the crank sensor. The crank sensor can swell up on the inside, then you have to take the oil pan off and take it out from inside.

In the past as you say, if the crank sensor was bypassed, I don't know how they would do that? I wouldn't know how to test.

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Friday, November 23rd, 2012 AT 1:36 AM

DAG2012

MEMBER
4 POSTS

Thanks for your help JDL. Turns out after the changed the CPS and it still didn't work that the garage finally changed out the ICM (Ignition Control Module) and that fixed the problem. It too bad they didn't checked that first as that is what I mentioned to them was what I suspected was the faulty part. Would have save me have the cost of the needless repairs. Anyway my Mom back on the road and is happy.

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Sunday, November 25th, 2012 AT 3:35 PM

JDL