Problem Getting Codes

Allan

Registered User
Hi everyone. Working on my son's '94 SC... again. His car has a 5-speed and a Moates tuner. He's has an EGR/vacuum leak that needs to be dealt with. Already have the bock-off plate and cap and will install it.

To me, the biggest problem is that I can't read the codes with either of my two EEC IV hand-held scanners. Both have new batteries and I do get signals to the scanners but they are incoherent. I don't get the engine identifier beeps or anything in the normal fashion (how it should according to the manual). This is a newer problem. It scanned before but somehow lost this ability a couple of months ago, according to my son. A month after that the car died in my driveway. Besides the EGR problem, there were some other things: PCV valve "fell" out of the valve cover and PCV vacuum lines were incorrectly hooked up. This has already been corrected.

My son said that although the code scanner method wasn't working, he was still able to datalog with his laptop.

First thing I am having him do is pull & reinstall the EEC to make sure the connector and wiring is fine.

Have any of you run into this code scanning issue?

Thanks,
-Allan
 
yeah i ran into it once on my 92, it was due to the hego wiring being shorted out, not saying this is your issue but it wouldn't hurt to double check the wiring going to both oxygen sensors

worst case... bad ecu, they have been known to burn the trace on the ecu which prevents them to stop dumping codes, this usually occurs after an extended crank when a 5spd ecu is used in an auto, but it could possibly happen
 
Thanks, I will check the o2 sensor wiring. I will check anything that's in that corner by the EGR also.

I'll have my son pull out the ECU for a look. The car was an automatic but he swapped in the 5-speed & correct ECU two years ago.

Hope it's something minor and easy to fix but I know better.
 
Thanks, I will check the o2 sensor wiring. I will check anything that's in that corner by the EGR also.

I'll have my son pull out the ECU for a look. The car was an automatic but he swapped in the 5-speed & correct ECU two years ago.

Hope it's something minor and easy to fix but I know better.

The EEC won't let you pull codes if it thinks the car is in gear. The logic is tricky and on a 94/5 there are wiring changes required for this swap to work properly. I know you said it worked before and suddenly quit, but I'm speaking from experience.
 
decipha, thank you for that link. I'll post what I find.

Dave, when we did the 5-speed swap I purchased and installed the correct 94/95 manual transmission harness. Is there anything else that should have been changed? I guess I should look over the clutch pedal and transmission wiring.

The only other problems we had were related to the DPFE and EGR system. This started when it was still an automatic though.

We installed your tuner last summer. I know he continued to have problems with the EGR (vacuum leak and DIY block off failure). Hopefully the new block off plate and EGR cap will get rid of that.

I'll try to get more info from my son about the problems he's had.
 
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