Code questions.... EGR???

[ThespecialistKC]

First off, a big "Thanks!!" to Mr. Shorty et.all who offered solutions to my detonation problem. Replacing the lower intake gasket cured approx. 75% of the problem. Soooo here we are 4 months later, and I finally get the time to scan the codes and pursue the remaining 25%. Soooooo....
The KOEO code came back as a 33, and the KOER came back as a 536. I know the 536 is from me skipping the brake on/off test, but the 33 is a fault in the EGR system. But.... I didn't think a '92 even had a EGR on it. Am I crazy (well, yes, but in regards to this issue...)? Am I missing something? If not, what would cause the computer to throw a 33 code? As always, thanks Gentlemen....

KC

 

[MrShorty]

Just like the KOER test, the KOEO and CM code should also be three digit codes. Are you certain those "33's" aren't really 111's?

 

[ThespecialistKC]

I though about that, but I'm pretty sure. It was three beeps/flashes, pause, three beeps/flashes, pause single beep/flash (separator I believe), then it repeats. Just to double check I'm going to pull the codes again tonight. I'll report back soon......
And thanks.....

KC

 

[MrShorty]

That sounds to me like a 111 (repeated twice as each set of codes should be). A 33 would be three flashes - pause - three flashes (33 first time)- pause - three flashes - pause - three flashes (33 second time) - pause - separator pulse - CM codes repeated twice.

 

[ThespecialistKC]

Soooooo, It turns out you are right (as usual) MrShorty. I bow in reverence. It was 111, not 33. Duh to me. Since I'm getting the all clear from the computer any ideas on my next step? I've already replaced the intake gaskets, cleaned the MAF, Seafoamed the engine and went through a complete tuneup. I'm still getting some detonation, even on 92 octane. My thoughts are to check the air intake for leaks behind the MAF, replace all vac. lines, then.... I dunno.... maybe switch to a colder range plug? Ideas? Anyone? Bueller?

 

[MrShorty]

Sounds like a decent approach. A couple of other thoughts:

1) Clogged fuel injectors have been reported to contribute to pinging. If the fuel can't effectively get through to the cylinder, that will contribute to a lean condition. You might try an in-tank fuel injector treatment and see if that helps. Or you might go straight to a more effective injector treatment like you see at shops, or pull the injectors and clean them up manually.

2) Have you checked the intake manifold bolts and made sure they haven't backed off a little bit? Have you checked the spark plugs for any clues they might have? That intake manifold is common enough, I would double check it. If you find deposits on the #5 plug, it's a good bet something still isn't right with that intake gasket.

3) Incorrect ECT data can theoretically contribute to ping, but not throw a code. You might consider putting a voltmeter/ohmmeter on the ECT and see if it's outputting something close to correct. If you don't have access to an IR thermometer or something like it, this might be most easily accomplished by pulling it out of the vehicle, hanging it in a pot of boiling water with your wife's/mother's/girlfriend's candy thermometer (if she'll let you) to see if it's reasonable.

3) O2 sensors have a lot to do with mixture calculations. Something in the O2 sensor circuit that causes the sensor to read a little rich may not throw a code, but will cause the mixture to be off a bit. I'm not quite sure how you would test this without a second O2 sensor, but it might be worth considering if you pursue this without finding any other solution.