theformula97

Was leaving my house today and as soon as I got out of the driveway and gave it a little gas, stumbled and died. Pulled off on the side of the road and tried to crank and just turned over but didn't fire. Waited a little and turned it over again and it cranked up with no hesitation. Put it in reverse and pulled back into my driveway and it ran fine all the way back up to my house. Gave it a few revs to see if it would do anything and found that it begins to stumble and backfire around 2700-3000 RPM(varies because I was able to rev it up to about 4500 with no stumbling). Pulled codes and got a p1371. Had this code before and had no trouble from it. Just wondering if my opti finally decided to die on me or if this is easy and its just a bad ICM.

Injuneer

The code sets when the PCM sees a large number of high res pulses with no low res pulse. When the code sets, the engine shuts down. If the engine is running, it is a stored code.

Appears the low res signal from the Opti may be intermittent. Check the harness connections (both ends) for corrosion or damaged pins. Check the wiring for damaged insulation.

theformula97

i know the opti harness was replaced by the previous owner so i’ll definitely check that out first. thanks a lot.

Injuneer

It's not unusual to find a greenish blue corrosion in the harness socket on the Opti. The vented Optis should be less prone. Make sure your vent harness is installed correctly.

theformula97

Okay thanks for input i’ll start checking on stuff Monday. It’s a 97 so it’s vented. Doesn’t the vent system have a few check valves?

Injuneer

From Shoebox:

http://shbox.com/1/opti_vacuum_hose.jpg

theformula97

Cool thanks. Another thing. Where would I even find an AcDelco or Delphi opti (if I happen to need one) in 2021? I can’t seem to find them anywhere and all the opti sellers talked about in this page 10 years ago don’t exist anymore.

Injuneer

I see people claiming they found an AC Delco. If they did, it’s a rebuild. I have no idea where they found them.

Current best replacement is Petris:

https://petrisenterprises.com/collections/frontpage

theformula97

Petris is sold out of the pin drives at the moment . I’ll have to do some digging on ebay and the internet to find a decent one if my Opti has decided to die.

theformula97

Replying to this again because I’ve done some testing. Followed shoebox guide and the ICM connector and the opti connector passed. Opti connector looks brand new, no corrosion or anything on it. Water pump not leaking on it and the cap screws were loctited. Could it be between the icm and the opti? Or could it be something else?

Injuneer

The Opti sends the data to the PCM. The PCM uses the data to know when to fire the injectors and the plugs. If you have the correct voltage to the white wire at the ICM, the PCM is doing its job.

Has P1371 come back?

Wondering if there is a problem with the cam dowel pin being too long and putting pressure on the back of the Opti. Or possibly oil leaking out of the Opti seal in the timing cover.

chevykid

this guy will rebuild and fully test your old one https://www.ebay.com/itm/23386716529...sAAOSwyfpfT7O3

theformula97

P1371 has been back ever since my car died leaving the house.

Just tested pin B on the ICM connector when I finally got someone to turn it over while I checked voltage. Tested multiple times and highest AC voltage I got was about 0.700. Shoebox said that there should be 1-4V every time the coil pulses. Led me to believe that it is the opti due to everything else in the ignition system checking fine and most of it being new. Pulled the opti and found oil pouring out of the opti seal on the timing cover.

Opti is a Spectra and lasted 2 1/2 years, which is longer than I would expect out of one of these.

Injuneer

The Opti will not affect the voltage of the pulse on the white wire. That pulse is developed and sent by the PCM. The pulse is a short 5 volt square wave. It's not just passing through the pulse produced by the Opti.

theformula97

Saw this a couple days ago. My opti is aftermarket(Spectra) so would he be able to rebuild it even though it doesn't have the Mitsu sensor? And if so would this be a better alternative to buying a Summit Opti? Because it seems like those are my only two options at this point.