Wolf95

Still having the original issue here, however runs extremely rough instead of dying right away. By now have new: Coil, Spark Plug Wires, Wires, MSD Optispark. Same deal. Once it gets warm and soaks it throws code 36. The Readings from the optispark harness were 4.72 on A and 4.73 on B. All other wires on ICM and opti harness test fine. (Was unable to test while cranking, no extra help). Once engine gets hot it idles at 1500-2000RPM too.

Injuneer

Does the engine run any better, or at the correct idle speed when the code sets and the SES light comes on?

I've attached the DTC 36 pages from the 1993 factory manual. As you can see, DTC 36 sets when there are less than the specified number of high res pulses between consecutive low res pulses. I'm not sure why they indicate "less than 60", because the optical wheel has 360 high res slots, and 8 low res slots. That would be 45 high res pulses on average between each pair of low res pulses. The low res pulses are variable width.

Interesting to note that in the 1994 version of the factory manual, they revised the description to "40 low res pulses occur before and high res pulses are detected." That would mean the cam turns 5 times (= 10 crank revs) with no high res pulse. The second page showing the logic tree for diagnosing the problem appears to be the same in both 1993 and 1994 manuals.

I can't explain that, but then I do find errors in these manuals from time to time.

Wolf95

Following that chart, I end up at that code 36 is intermittent, do you by chance have the back side of that page as well?

Injuneer

If you are looking for "diagnostic aids", that's at the bottom of the first page. There are no additional pages for DTC 36.

GaryDoug

Keep in mind that the pcm uses the low res pulses to determine how to count the high res pulses. So if the low res pulses are very intermittent/noisy it will count too few high res pulses in what it thinks is the allotted time, even if the high res pulses are ok. The problem may be due to there being too many pulses on the low res line than normal. I would recheck the cable. If not that, the problem may be with the pcm or the dc power going to the Opti. The fact that you only have 4.7 volts instead of the normal 5.0 seems to point to the pcm.

Wolf95

I sent the PCM to a PCM repair company, and they weren't able to get it to replicate after heat soaking. I'll be cutting apart the wiring harness to see what I can find in there.

K-Boy

hey did you ever find the problem ?

Injuneer

"Wolf25" hasn't signed in to this site since his last post above, 7 years ago.

If you have a similar problem, why not start a new thread with details about your car, and the symptoms of the problem you are having?