Ok, yesterday, I went to Mike's (pnoymahal) house to do a compression check. Once I removed my spark plug wires, we noticed that there was oil in the spark plug wells, and that my spark plugs had a lot of burnt residue, prolly burnt oil. Mike said it was just prolly the gasket/O ring seals that was leaking and that it was an easy fix. Just wondering what other worse case scenarios might there be. Hopefully that's just it.

And on another note, I also have a CEL 21, which is the o2 sensor. We used Mike's datalogger and the datalogger stated that there was no activity in o2 sensor #1. Anyway, the thing that I was wondering about is that whether I should get any signal from the ECU to my a/f gauge. Cuz I thought that the voltage from the O2 sensor is what is sent to the ECU, then this is the reading that I get from my a/f gauge. Then how come I'm still reading some activity from my a/f gauge? Its the blinky blinky one, I know its not accurate, but I thought I wouldn't get any signal at all, or at most, I'd be running really lean. But my a/f gauge seems to be showing no difference. It still moves back and forth from lean->stoich->rich, and during WOT, it goes all the way to rich. Just wanted some input. TIA

CEL 21 could indicate one of several things wrong:
PO134 - Upstream H02S stays at center
PO132 - Upstream H02S shorted to voltage
PO133 - Upstream H02S response
PO135 - Upstream H02S heater failure
PO139 - Downstream HO2S stays at center (M/T)
PO141 - Downstream HO2S heater failure (M/T)
PO138 - Downstream H02S shorted to voltage

You'll have to scan it to find out exactly which one it is.


95 Eclipse RS : 5 speed
15.901 @ 88.34mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

As stated earlier, datalogger stated that there was no activity from the o2 sensor. I forgot which actual code it was. Any other ideas?

I would pull your connection from the af guage to the ecu. reset ecu. fire it up. Get the CEL again? if ya might be needin a new sensor.

If it goes away your connections with the guage either grounded or at the ecu are fucked. might be the gauge itself (like me)

The datalogger says no activity from o2 sensor #1, but thats the sensor feeding a signal to your a/f gauge? I'd try looking at the possibility that the signal was re-routed to go only to the gauge instead of going to the gauge and ecu both maybe. in other words, its hooked up to the gauge now but not the ecu.

Uh, the a/f gauge I think is connected the normal way, which is the black and white wire from the ECU. So does this make any sense that I'm getting readings from my a/f gauge even tho my o2 sensor is supposedly dead?

>So does this make any sense that I'm getting readings from my a/f gauge even tho my o2 sensor is supposedly dead?

Maybe. If the sensor isn't reacting quick enough then it'll throw a code P0133. On a gauge it'll still look like its working, but its not working fast enough for the ECUs liking. Maybe your friends datalogger gave you a misleading label for the P0133? Does his datalogger just give you a message or can it give you the actual code?


95 Eclipse RS : 5 speed
15.901 @ 88.34mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

Yeah, the datalogger that he uses gives both the code and the label. Its the program used by RRE, if I remember correctly from Mike. I guess the o2 sensor must still be slightly working then, prolly just not that much anymore. Cuz I'm still getting 26-28 mpg on a full tank.