Opti Problem?

[Jodirte]

Hey folks. Looking for answers if possible. Bought a 97LT1 Firebird HCI car. After having it a few days it pulled a P0372 code, usually directly after it took a few times to start. Car seemed to run pretty good otherwise for a decent size cam car. After reading all the opti horror stories I decided to replace the 2 year old Dynaspark with a Summit opti 2. I have a reputable shop doing it and I trust them 100 percent. After the Summit opti, no more P0372 but the car read P0336 and it seems that the timing is slightly retarded out of spec. Replaced crank sensor, no change. Ordered a Petris opti and put it in... Same story P0336 timing seems to be retarded. Opti harness is new. Just looking for some honest answers or if someone has suggestions as where to start. Thanks!

[Sahara54]

Did they test the wiring for the CPK? Maybe he connector is bad or a break in the wires.
http://shbox.com/1/1996_ec_03_ign_system.jpg

[Jodirte]

Yes, to my knowledge the CPK on 96 and up cars only provides OBD2 codes anyway. Doesn't really control anything. I believe though it probably is working and it sees the timing is out of spec, and the car not running correctly indicates that also. I just see a lot of threads of optis installed incorrectly most have a no start problem but I have seen several that actually did start and ran. So far the only change has been the opti so I'm just trying to eliminate anything that could be related to the install first. I find it pretty unlikely that I have 2 defective new units from different places-especially the Petris because it seems to be a very solid piece.

[Injuneer]

The CKP provides data for misfire detection. The PCM is looking at the rotational velocity of the crank, based on the 4 poles on the CKP. The PCM compares those signals to the high resolution pulse (cam position signal) from the Opti, to determine if the pulse signal from the CKP is deviating from the known effects on the crank velocity of each cylinder firing. The PCM needs clean signals from both the CKP and the cam position sensor to make the calculation.

If the difference between the CKP signals and Opti signals falls outside a defined range, you get P0336. This can be due to:

- faulty CKP
- loose crank reluctor
- crank reluctor contacting timing cover
- CKP sensor contacting reluctor
- excessive timing chain play
- faulty/erratic hi res signal from the Opti
- interference on the signal wires (CKP or Opti) due to nearby high voltage discharge (e.g. plug wire)
- poor wiring connection for either sensor
- excessive distributor drive backlash (dowel pin not in correct index hole)

P0336 addresses small angular deviations in the signal (-10° to +7°)

P0335 address larger angular deviation (-21° to +51°)

[beaver50]

The CKP provides data for misfire detection. The PCM is looking at the rotational velocity of the crank, based on the 4 poles on the CKP. The PCM compares those signals to the high resolution pulse (cam position signal) from the Opti, to determine if the pulse signal from the CKP is deviating from the known effects on the crank velocity of each cylinder firing. The PCM needs clean signals from both the CKP and the cam position sensor to make the calculation.

If the difference between the CKP signals falls outside a defined range, you get P0336. This can be due due to:

- faulty CKP
- loose crank reluctor
- crank reluctor contacting timing cover
- CKP sensor contacting reluctor
- excessive timing chain play
- faulty/erratic hi res signal from the Opti
- interference on the signal wires (CKP or Opti) due to nearby high voltage discharge (e.g. plug wire)
- poor wiring connection for either sensor
- excessive distributor drive backlash (dowel pin not in correct index hole)

P0336 addresses small angular deviations in the signal (-10° to +7°)

P0335 address larger angular deviation (-21° to +51°)

That injuneer is pretty smart on this stuff

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[Cathead]

That injuneer is pretty smart on this stuff

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I agree. He's helped me more than once, directly and indirectly.

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[Injuneer]

Did you have the "retarded timing" feel with the DynaSpark? Or just with the Summit and the Petris?

A few ways the timing can be "out of spec".... opti drive indexed incorrectly (dowel in cloverleaf, rather than index hole), shutter wheel in Opti offset, sloppy timing chain, dot-to-dot on timing set incorrect, HV interference adding pulses to high res signal from Opti, cam grind off or cam offset incorrectly. Whether you had the problem with all three Optis, or only the last two would rule out some of those possibilites.

You could be experiencing knock retard that is giving the engine a slow feel.

[Jodirte]

Did you have the "retarded timing" feel with the DynaSpark? Or just with the Summit and the Petris?

A few ways the timing can be "out of spec".... opti drive indexed incorrectly (dowel in cloverleaf, rather than index hole), shutter wheel in Opti offset, sloppy timing chain, dot-to-dot on timing set incorrect, HV interference adding pulses to high res signal from Opti, cam grind off or cam offset incorrectly. Whether you had the problem with all three Optis, or only the last two would rule out some of those possibilites.

You could be experiencing knock retard that is giving the engine a slow feel.

Thanks for all the info. The car ran bad ass with the Dynaspark mid-range, top end, WOT. However it would be hard to start every once in awhile and would afterwards go P0372 code. I also noticed low idle was rough at times, drop way too low in my opinion and slowly creep up, and also some random pops back through the exhaust cruising. I read enough on the optis to "assume" the Dynaspark was up for a replacement (which I confirmed today-full of oil, and bearing is getting sloppy), but honestly it ran pretty good. Keep in mind I have only had the car at this point a few days and maybe 2 hours drive time and it went straight to the shop for new opti. The car has rebuilt bottom end with less than 20k with new LT4 gears and chain. So new summit opti 2 goes in, with new opti harness, shop calls and says it pretty quickly sets hard P0336 code. Timing at idle retarded by 15-17 degrees, car ran OK but we decided to replace CPK, check wiring, check reluctor, etc. no change. I didn't have much faith in the Summit unit so I ordered one from Petris and it seems very well built with correct hoses. Anyway installed, started it up, same issue. Timing is retarded and it actually sounds to be running a bit worse, the car is definitely not running right, barely driveable, backfires through exhaust. Anyway scoped the CPK today and OPTI and signal looks good. Tomorrow looking for wiring issues. Really do appreciate the help!

[Jodirte]

Wanted to add no knock codes or indications on the sensors. My first thought was that the dowel is not located correctly and is in that clover area. However it looks like you would have to force it on to do that because the cam bolts would be hitting face of opti? I also checked the summit opti after removal for any marks in the clover area to indicate it was not aligned correctly.

[Injuneer]

You sure the scanner doesn't just report ignition advance as a negative number? Some do. Confuses people. Typical advance at idle will be around 18°-22° in a stock tune. No idea what the tuner might have done to tame the big cam.

Or is the scanner actually reporting knock retard? Generally, the max retard the PCM can set is 15°. Tuner can change that, but generally they lower it.

The only codes for knock are for failure of the sensor (P0332) or the knock module (P0325). If a failure code sets, he PCM defaults to an (almost) full time ignition retard based on throttle, RPM and MAP. You might see knock retard at idle.

As difficult as it seems to be to mis-index the Opti, you would be amazed to see how many times it gets screwed up. Did they replace the Opti seal in the timing cover?