Can an opti crap out without throwing a code?

 

yes!

 

Oh joy.............

 

Give symptoms maybe we have other ideas.

 

If the optical sensor (and its wiring harness) has problems, you will get codes for the missing high and low resolution pulse patterns. If the problem is on the high voltage side, no codes are set specifically for the Opti.

 

'97 Z28
108k miles
CAI
Racetronics fuel pump
ELP
Borla catback
Custom piggyback tune

Several weeks ago I was on the way home from work, 17 mile drive. Half way it started misfiring like crazy. Stopped and looked under the hood to see if it was anything obvious. It would run but it was not going to get me home. Called GEICO and had them send a tow truck. Got it home and it ran fine. Couldn't get it to mess up. No codes thrown.

Fast forward a few weeks. On the way home again. About 5 miles into the drive the car dies. No stutter, no skip, just died. I pulled over to the side and checked the ScanMaster for codes. There were none. After I sat for a minute I tried to start it. Started right up. Drove it home and it ran fine. Headed to the grocery store the next morning. 1.5 miles from the house it dies again. Won't restart this time. Get on the horn again with GEICO again. Same tow truck driver shows up and deposits me back in my driveway.

Wouldn't start a few hours later. Tried several times. I could hear the fuel pump running but I don't know if its getting to the intake. I yanked the CAI off to get a look at the TB. Hooked a FPG to see if fuel pressure was getting there. Looked fine. Put the CAI back on and gave it another try. It started right up! Let it idle for about 45 mins. That was 2 days ago. Have gone out and started it up several times since. Always starts. Haven't driven it anywhere yet. Don't feel like getting stranded again.

 

mine died and i didnt get a code either.

 

Any suggestions?

 

ICM? It may be failing when the engine gets warm.

 

Yup I would put money on it

 

I was thinking along those same lines until the last event. Last time it crapped out on me I was about 1.5 miles from the house and the temp needle hadn't even moved yet. Keep those ideas coming.

 

it doesnt take the engine being hot to burn out the ICM. the heat generated from the unit itself will cause failure if its already failed... ICM falures happen EXACTLY like you stated. The ICM will start right back up a couple times then you have to wait a little longer and the stalling will happen more often untill it wont even fire. I would replace it or test it with a known good one since even a test can report a false positive.

 

Thanks for the info. Good thing I have two '97s, eh? LOL

 

UPDATE: I finally got the car to hard fail. Zero fuel pressure. A wire in the fuse connector at the alternator was loose on the Racetronix harness. Thank God for an easy fix.