Maddening code P1371 / another no start LT1
Maddening code P1371 / another no start LT1 Getting code P1371 on my 97. Obviously it also does not start, though did a few times intermittently before it gave up entirely.
I checked both the ICM and Opti connectors, even replacing both opti connectors (both the part that plugs into the opti itself plus the connector on the intake manifold, partially because the intake manifold one was actually broken/not making a good connection). I didn't get any weird outputs for the connectors after that (5v/5v/12v/ground) EXCEPT the opti ground was a bit higher than normal... about 3-4 ohms with the key off.
I did the drill test too. Spinning the spare opti with a drill. Should eliminate wiring, the PCM, ICM, coil, wirng, fuses, etc, right? I know only the opti, opti/pcm wiring, and pcm are part of code P1371, but nice to eliminate other stuff anyway. Got spark while spinning the opti and DID NOT get code p1371.
According to the checklist as well as the opti drill test, seems like a case closed case of the opti, right? So I get ready to replace it. I pulled the water pump Friday and let all that stuff drain/dry up overnight.
Yesterday I get out there ready to pull the balancer off so I can pull the opti. Then I notice my ground strap was hanging on by a thread (the ring terminal broke off on the ICM bracket/cylinder head). I replace the ground strap with some 10 awg wire. Then I figure why not and hook up the minimum stuff I need to start the car, no drive belt, no fans, no water pump and start the car. It starts! No codes. I started it three times. All fine. Even let it idle for 30 seconds. All fine. No codes, no running rough, no nothing abnormal.
So I grumble about having pulled the water pump for nothing and reinstall it, put the fans, belt, everything else back on.
Then...... I go to start it........ code P1371.
WTF gives here?
I checked both the ICM and Opti connectors, even replacing both opti connectors (both the part that plugs into the opti itself plus the connector on the intake manifold, partially because the intake manifold one was actually broken/not making a good connection). I didn't get any weird outputs for the connectors after that (5v/5v/12v/ground) EXCEPT the opti ground was a bit higher than normal... about 3-4 ohms with the key off.
I did the drill test too. Spinning the spare opti with a drill. Should eliminate wiring, the PCM, ICM, coil, wirng, fuses, etc, right? I know only the opti, opti/pcm wiring, and pcm are part of code P1371, but nice to eliminate other stuff anyway. Got spark while spinning the opti and DID NOT get code p1371.
According to the checklist as well as the opti drill test, seems like a case closed case of the opti, right? So I get ready to replace it. I pulled the water pump Friday and let all that stuff drain/dry up overnight.
Yesterday I get out there ready to pull the balancer off so I can pull the opti. Then I notice my ground strap was hanging on by a thread (the ring terminal broke off on the ICM bracket/cylinder head). I replace the ground strap with some 10 awg wire. Then I figure why not and hook up the minimum stuff I need to start the car, no drive belt, no fans, no water pump and start the car. It starts! No codes. I started it three times. All fine. Even let it idle for 30 seconds. All fine. No codes, no running rough, no nothing abnormal.
So I grumble about having pulled the water pump for nothing and reinstall it, put the fans, belt, everything else back on.
Then...... I go to start it........ code P1371.
WTF gives here?
Last edited by Z28Roxy; Nov 29, 2020 at 10:28 AM.
Doesn't it still run even with a bad crank position sensor?
I guess I'm going to replace my opti, but still very strange how it went from barely starting to not starting to starting and idling perfectly (when I replaced the ground strap) to not starting at all again when I put everything back together. Just wondering if anyone has run into this type of issue before and what it might be. Maybe the rotor screws are ever so slightly loose?
I guess I'm going to replace my opti, but still very strange how it went from barely starting to not starting to starting and idling perfectly (when I replaced the ground strap) to not starting at all again when I put everything back together. Just wondering if anyone has run into this type of issue before and what it might be. Maybe the rotor screws are ever so slightly loose?
