SS RRR

iTrader: (2)

Just because you hear it doesn't mean it is working properly. No reason why you shouldn't at least check the fuel pressure with a gauge if that hasn't been done already?

Bow Tie Power

I can see how that would prevent a car from getting fuel but I don't see how that would prevent a car from getting spark.

SS RRR

iTrader: (2)

It doesn't. Process of elimination. It takes minutes to check your fuel pressure.

Bow Tie Power

We just checked it. It's in between 40-45 PSI.

Bow Tie Power

Could this be caused by a bad opti harness?

slingshot928

When I had your same problem, the ground to my ewp broken leading to a whole slew of problems. Get a multimeter and check all of your ground wires (with resistance to check for breaks) Also kind of an odd trick that would get the car to fire up when the grounds were broken, I took off the first spark plug on the drivers side to check for spark and the car would fire up (i think it grounded the ignition system) otherwise the car wouldn't start (had fuel pressure, etc.) Ended up replacing the icm and coil also with ac delco parts because the broken ground from the ewp also shorted out those...only sometimes the codes 41 or 42 would appear during testing. (I have a 93, so it is easy to test for codes by inserting the paper clip into the connector under the dash)

Check shbox, he has references to what voltages should be coming out of what wires (for icm, etc). Also, if your car starts, wiggle the opti connector to see if it is a bad connection (or you can take it off and check it with the multimeter to check for breaks (best 30 dollars ever spent).

Bow Tie Power

If there was a bad ground, wouldn't the car refuse to start? It'll start and run perfectly for about 20 minutes.

slingshot928

My car would run for hours, then wouldn't start again. It would run for 20 minutes, then wouldn't restart. If you would jump the fuel pump (put 12v to the wire by the computer to prime the fuel pump) it would run. Code would appear, then disappear.

Just sharing what happened to me. Take some time to think about it and learn the car's electronics instead of throwing parts at it. At one time I thought throwing new parts at the car would fix it, but with any car you need to diagnose it properly.

Bow Tie Power

I'll definitely check into that. Thanks a lot!

Bow Tie Power

UPDATE: A good friend, my brother and I decided to examine a few sensors. After the car died, we wiggled the wires that go to the oil level sensor and she fired right up! We wiggled them again to see if it would kill the car and it did. We cranked it over to see if it would start and it wouldn't. We wiggled those wires again and it started right up again. Looks like we MAY have found the problem.

fbody_brian

Glad you were able to sort it out.

Makes the car much more enjoyable to drive when you aren't worried it will shut off at any moment.

Bow Tie Power

^^^ So so true! We will find out this weekend if that's the official issue or not.

Bow Tie Power

We should be checking the theory of the pig tail to the oil level sensor Saturday or Sunday but I do have a question before then. Does it seem odd to anyone else that problems with the oil level sensor would prevent a car from getting spark?

fbody_brian

Yes does seem strange

"PCM checks engine oil level during engine start-up. If oil level switch indicates oil level is low, PCM will send this information through the serial data to the Instrument Panel Cluster (IPC) to illuminate the "Low Oil Level" warning light. Oil level is checked once per ignition cycle and also after ignition is turned off to allow oil enough time to drain back into oil pan."

Bow Tie Power

Exactly. And my low oil level light is NOT on. I don't get it. Unless there's a bare wire grounding out somewhere?

Bow Tie Power

It appears my horrible luck is still playing out. The theory about the oil level sensor was false. We recently put the scanner on it again and found out that the temperature on the scanner was reading -40* C, even though my gauge works correctly. There are two temperature sensors: One on the water pump that goes to the PCM and one next to the headers which goes to the gauge. It appears to us that the coolant temperature sensor on the water pump is bad.

My next theory is a bad CTS could send a signal to the PCM with a bad reading, causing the PCM to shut the car down and prevent spark. Do you guys think that sounds like a possibility or does it sound like a stupid idea?

SS RRR

iTrader: (2)

At this point I'd think you could find another harness to try out?

fbody_brian

I would actually think not. I had a bad pigtail on my coolant temp sensor. It would read like the engine was super cold, the pcm would dump fuel, the car would buck and stall and surge.
It never really just died, and it never caused a no spark issue. You very well may have a short in the harness causing the issue, but I'm willing to bet that the coolant temp sensor isn't it.

Bow Tie Power

I had talked to someone on another forum. He told me he replaced about $800 worth of parts because of a no-spark issue only to find out it was his temperature sensor but I'm not sure if he was telling the truth or not. Anyway, AutoZone doesn't sell a pig tail to the CTS unless you buy the sensor as well. They have the sensor for $14 or $16 for the sensor and pig tail. Think it'll be worth trying out?

fbody_brian

I think it would be worth it, not because it may solve your issue, but because if it is reading -40 it's bad.