ECU Code 32 EGR Function

[94pathynewbie]

I guess I should make my own post despite there being many others, however I'd like to get some others' opinions on if I should go this route before buying anything. (dang it I just answered it in my own head because I know the answer) 

 

When I first purchased my old lady, I had found out later than the EGR Temp Sensor? Maybe wrong name.. was left disconnected by the previous owner. It was completely covered in soot to the point I could not just wipe it off. I have to admit; I did a poor job at cleaning it and basically left it black before I plugged it back in.

 

My question.... Could this sensor just need to be removed again and properly cleaned to clear my ECU code 32, or would the soot not be an issue for this sensor? I should have done it by now, but I suppose after barley putting the plenum back on, I am just dreading taking it off again.

 

Whatever. Anyhow... Appreciate all input from you guys! I'm still learning a lot from this forum. 

Edited 3 hours ago by 94pathynewbie
to make sense

[Slartibartfast]

I would start with the troubleshooting for code 32, EF&EC-93. (Download the service manual from Nicoclub if you haven't yet!) Rule out the vacuum lines (just replace them if they're original!), the EGRC solenoid, the EGR valve, whatever else the manual says to check. IIRC my '95 had a short hose under the EGR-BPT (the UFO-looking diaphragm deal beside/above the EGR valve) that had burned through on the back side, so I'd check for that too.

 

There's also a test for the temp sensor. EF&EC-135 says to test the sensor at 100*C/212*F. It should read 85.3k ohms (plus or minus 8.53 ohms) at that temperature. If it was open or shorted, it would be throwing code 35, but it is possible it's just drifted far enough off spec that it's lying to the computer. The temperature it reads corresponds to how much exhaust is flowing through the EGR valve (more exhaust = more heat), so if it's reading low, that could make the computer think the flow is lower than it's supposed to be, causing your code 32. 

 

The temp sensor lives in the dirtiest part of the engine. Unless it's crusted up on the tip of the sensor like the corn on a corn dog, I wouldn't expect the soot to insulate it enough to matter. Might be worth cleaning it if you go through the rest of the troubleshooting without success, or if you have it out anyway, but I'd be surprised if that was the problem.

 

Carbon buildup in the valve and/or manifold could also be decreasing flow. I've heard of the EGR on the old TBI engines blocking itself up completely. I haven't heard of the multiport (what we've got) doing that, but the EGR port in the manifold on my '93 looked like those "this is what cholesterol does to your arteries" posters at the doctor's office the first time I had it apart. (It wasn't coding, but it's the earlier/federal-smog system, with no temperature sensor, so the computer would've had no idea.)

 

The unplugged sensor makes me suspicious that the PO might've been tinkering. I've read that you can get away blocking off the EGR on the federal-emissions trucks, because they don't have the temp sensor. Perhaps the PO blocked the EGR (either to bandaid a bad EGR valve, or because racecar yo), the temp sensor ratted him out, he unplugged the temp sensor, that didn't magically fix it, and then he sold it to you rather than fix it properly. 

 

Good luck!