Cam sensor, ECM, or prom???

[Fred 86 GN]

Car wouldn't start for on me at the track without giving it gas then it did not want to run. The "check engine" light was flashing very fast with the key on or when the car was barely running. Couldn't get any codes from DirectScan or the ScanMaster, they were acting very screwed up. After unplugging the power to the ECM and removing then reinserting the prom, the car started and ran fine.

This happened once before at my house, about eight months ago. Then it created a code 51 -- bad prom. I ended up unplugging the ECM and removing then reinserting the prom. The car has ran fine since then till this episode this weekend.

After reviewing my DS files from this weekend, the last one had two codes in it -- for about one second -- before they "self cleared". That DS file was messed up too. Numbers jumping around everywhere. Anyways, the two codes were 41 and 42 -- cam sensor first, then the C3I had a problem. Or the ECM could be bad to cause them too.

Car ran fine on the way home.

So do I have a tempermental prom, ECM, or flaky cam sensor??

What else could it be?

Thanks,

 

[bruce]

Originally posted by Fred 86 GN
Car wouldn't start for on me at the track without giving it gas then it did not want to run. The "check engine" light was flashing very fast with the key on or when the car was barely running. Couldn't get any codes from DirectScan or the ScanMaster, they were acting very screwed up. After unplugging the power to the ECM and removing then reinserting the prom, the car started and ran fine.

Sounds like a flakey Prom or Prom socket (disclaimer hard to see it from over here).

Cheapest option is just to reburn a prom if you're doing them yourself.
If not, then you should have a spare ecm around for times like this to test it.

 

[Fred 86 GN]

Thanks Bruce!

I guess I should buy a new ECM "just in case". Course the error only has happened only twice in eight months. This is quite an intermittent to chase! Funny, if the ECM or Prom are flaky, then why did the car act like it had a bad cam sensor this time? (runs OK till shut off then won't restart)

I really had a good chuckle when reading your signature. I don't get the stopwatch/VSS either (?).

 

[Fred 86 GN]

Found problem.

The prom was bad. It was of a questionable pedigree anyways. So it came out and a Reds 100 chip went in. The car runs normal again now.

FYI -- if your check engine light flashes REALLY fast, like at timing light speed, then check the chip. Power down, remove from socket and re-insert. That may fix the problem. If not, replace the chip with a known good one.