Code 36 and hard starting

[tazman71]

Car ran fine a little over a week ago. Then was parked in the garage. A few days ago, I went to move it, and it was hard to start and threw the SES light.

Had the car scanned and came up with a code 36. No other codes were found. The car will start after several seconds of cranking. I drove it, and it feels sluggish.

Did some research, and ran into the sticky on the codes. Ran through some diagnostics. I get just under 6v at terminal B on the harness. Can't get to the distributor end to check the voltage there, but not expecting any change there. Does this verify the Opti is going out, or is there still anything else I should check first before I tear this apart?

[Injuneer]

Are you using Shoebox's guide to testing the Opti harness and the ICM harness? The 5V spec on pin B of the Opti harness is the reading with the harness off the Opti, hence you are measuring the reference voltage supplied by the PCM. Factory manual accepts anything in the range of 4 to 6 volts.

http://shbox.com/1/4th_gen_tech2.html#opti_test

In theory, the PCM can function with only the low reference pulse, with a minor loss in timing accuracy, that you typically would never notice.

Try and reach the connector at the Opti. Could be corroded or damaged pins.

[GaryDoug]

Continue measuring pin B with the cables plugged in at both ends. While cranking, the reading should be around 2-3 volts DC (not ac) if the hi resolution signal is present. You can pull the injector fuses out to prevent starting while measuring this. If it stays steady at 4-6 v dc, the cable or Opti is defective. Delayed starting is a symptom of a missing hi-resolution pulse, because without it the pcm takes longer to determine the correct firing position.

[tazman71]

Thanks guys.

Hope to be able to check it the next couple of evenings. Will respond back on what I find.

Planning to take the car down to LTX shootout. I know I will not have it fixed by then, so guess I am going to have to trailer it. At least it runs to get it in and out of the trailer.

[tazman71]

Where is the best place to get a new opti? I need a non vented opti for my 94. Thanks

[popo8]

We used to have a vendor on the forum who sold the rebuilt delcos... im thinking GM or ROCK AUTO is the only way to get one now.

LTXtech.com IS my drug...
OWNER/ADMIN

[coZ28]

I had the same issue recently. I found the wires from the PCM had gotten hot and the insulation had begun cracking. I clipped the pigtails off (with enough slack to re-pin, and also to know what wire goes to what) and crimped on some weatherproof male/female connectors. Cured my hi-res problem. I'd check all your connections and make sure your pins are seated in the connectors well. Start cheap, or you'll be mad when you spend money on a new opti and it still throws the code.

~A~