2000 Saturn SL1 - 90K. All fluids checked, drove car to store ten minutes from my home. No warning lights. Came out half an hour later, car would not start, all lights on dash on. Finally got it to run, but it would soon die. Towed to shop, kept two days, found nothing wrong. I used CARmd and got no codes. However, when I drove it a short distance today, I barely made it home. As you drive, the idle speed decreases. You are OK at the first red light, but by the third, the engine dies. The first few times it dies, you can restart it, but then it gets to the point that you cannot. I used a bottle of HEET in case. I am in my 70's, and I need to be able to rely on my car.

 

Sounds like Crankshaft Position Sensor (CKP) is on its way out.

The device sends a signal to the PCM to let it know where the crankshaft is in its rotation. If the PCM does not receive a valid signal from he CKP, the PCM kills spark and turns off the fuel injectors as a safety measure, since the PCM no longer knows where the engine is in its rotation, and therefore where the pistons are and which way they are traveling.

The CKP on the S cars is notorious for behaving as you describe when beginning to fail, From a cold start, things seem fine, but once the engine and CKP heat up, the CKP "malfunctions", doesn't send its signal to the PCM, and the car shuts down from lack of fuel and spark.

The "I drove to the mall and came out 30 min later to a car that would crank but wouldn't start" is classic dying CKP behavior.

If you think about it, the air rushing past the engine and associated components plus the circulating coolant helps to keep things cool. When you park the car, no more air assisted cooling or circulating coolant; the engine and many things under the hood begin to heat up.

If the CKP is marginal and dying, it will not function correctly as the engine temp increases, and there will be no spark and no fuel. You can crank all you want, but it's not going to start. If you wait long enough for this marginal failing CKP to cool down, it begins to function properly again, you get fuel and spark back, and it start right up.

It's a heat/teperature related issue.

As far as the decreasing idle speed, stalling, and restarting only a limited number of times thereafter, the engine is not yet warmed up so it is prob idling at about 1200 rpm. As the engine warms up, the idle naturally decreases towards the 700-850 rpm range.

But as he engine warms up, so does the CKP, and we know what happens from the description above. Once he CKP temp reaches a temp at which it malfunctions, you end up (again) with a car that will crank but not start. So again it is a temperature related issue with the engine and the CKP heating up, triggering failure of the CKP and shutdown of fuel and spark, causing the engine to stop running.

If you wait long enough for it to cool down, hopefully it will resume proper operation and you can start the car.

Needless to say, this is a "ticking time bomb" situation since eventually the CKP will stop functioning altogether and the engine will simply stop. And not restart.

Normal resistance across this sensor is 700-900 Ohms. A dead or dying one will be out of spec when in failure mode.

Hope this helps

Derf

 

Thank you very much!

 

Glad to help out.

And thank you for taking the time to come back and thank us. Few people do.

 

I can't disagree with derf, but I'd check that catalytic converter too. Maybe that sum beech is clogging up.

 

I took from the size of the Thank You font that the problem was resolved.....

 

I'm afraid the font size was chosen because I am legally blind. The car is still sitting in the driveway. No work has been done on it. A mechanic was supposed to come and look at it Sunday afternoon, but he did not call or come.

Plan B: A GM mechanic with a local dealership who makes house calls after hours is supposed to come to look at it after he gets off work today. Fingers crossed.

 

Fingers crossed indeed.
I hate no shows

Part is

ACDELCO 21020140 GM Original Equipment
CrankShaft Position Sensor $25.79 at RockAuto.com.

With dealer mark up, he should charge you no more than $50.00 for the part

He can fix it in your driveway if he can get the front of the car high enough.

It can be done without removing the starter but must be done w w a mirror and totally by feel.

Or he can pull the starter, which takes longer but gives free access to the crank sensor

If he had a car lift, it'd take him 10 min to do.

Labor should be no more than 30 min.= $50

So $100 is reasonable.

ARGUE OVER PARTS COST AND LABOR COST and play the "old lady" card (sorry).
Older women who do not know what's going on w a car are easy pickings for unscrupulous auto shops.

Knowledge is power.

Print out my post and show it to him.

 

I thought the second mechanic was going to be a no show too, but he got here about 9 pm. He brought his wife and a big dog who sat politely in the back of his pickup. When you get to be as old as I am, everybody looks like they are 12 years old, and this mechanic and his wife were no exception.

By 9 pm, I am ready to crash and burn so I did not hang around to watch him work. I don't have a garage, and it was dark as a pit out there anyway.

I have ramps, but he did not use them. He had gotten the part, and it took him 40 mins.to install it. He drove the car, said it was fine, and billed me $25 for the part and $50 for his time. He gave me the receipt for the part and the box it came in. He left about 10 pm.

Today is a dangerous ozone day. It is also in the 90's with high humidity. Too hot for me so I have not yet driven the car.

Now I have another question. The shop that kept the car for two days, said they had repeatedly driven it and nothing was wrong....should they have been able to diagnose the problem with car?

 

was it indeed the crankshaft position sensor that he replaced?
For 40 min, he must have pulled the starter, which is fine. Why he would not want ramps is beyond me.

Talk about honest. If it was indeed the CKP, his parts markup was low and his labor was reasonable.

The easiest way to test it is to let it run in your driveway for about the time you would take to get to the store. Then turn it off. Immediately try to restart it. Then wait the 20-30 min and try to start it again. You're simulating what was happening before, only in the comfort of your own home and with no risk of getting stuck somewhere should the repair have gone wrong until the sensor cools down.

Did he give you the part he replaced?

Of course do not go out in conditions hazardous to your health.

But please do come back and let us know if all is well.