Codes 25 and 26

[Neil]

I unplugged my charcoal canister the other day, and today on my way home my check engine light came on. I checked it soon as i got home and it gave me codes 25 and 26, (rich, and lean). I plugged it back in and reset it drove it around for only like a mile cuz i need some sleep. it didn't come back on yet, but last time it took about 35 miles of driving for it to come on.

Isn't that kinda of awkward to run rich and lean at the same time... oxymoron:thumbup: Just curious if anyone else has had the same problem, and if it comes on again what the deal could be.

Thanks,
Neil

 

[CRE]

Getting both codes at once is unlikely... but, given how quickly and frequently the ECU makes changes to the fuel supply it's not unlikely that the system might over correct for one condition causing the other in a very brief amount of time.

When you disconnected the charcoal canister did you cap the hose leading to the throttle body? You might have been letting in too much unmetered air. How did you run the rest of the lines?

 

[Neil]

Actually, I just capped both lines.

Neil

 

[Murd]

I had that happen to me. I ended up doing a tune up and found a fouled plug and a cracked vacuum line. Replaced both and codes went away. Still "seems" to be running rich, but I'd rather have rich than lean and it's not pulling codes. Another person I've talked to replaced his injector o-rings and that fixed his problem.

 

[Neil]

Hmm, well I havn't gotten any codes yet, but I've only been to the school and back, we'll see what happens when i run into the other town. Thanks for the info.


-Neil

 

[Neil]

The check engine light came back on with the same codes... It takes a while to happen after i reset, after i check the codes... I will check my vaccume lines as much as i can in the mornin'.
Any suggestions on the possible cause of this problem would be great. Cre's suggestion about it overcorrecting sounds plausable but I just don't know what would be causing it to run lean and rich..


Thanks,
Neil

 

[CRE]

Have you checked all the usual suspects? O2 sensor, spark plugs and wires, distributor cap and rotor, ignition coil? The next couple things would be fuel pressure regulator and damper.

The next two things I would check are the TPS and AFM.

 

[Neil]

Will do in the mornin'...

 

[Neil]

So I opened my hood to check things out, look down to my O2 sensor and the fking wire is cut! I have no idea why it could be but it was a clean cut, I'm assuming this is my problem..?

 

[CRE]

Probably... I'm surprised. There are very few situations were you can run a 7M without an O2 sensor. I assume you don't have any piggybacks installed?

 

[Neil]

Nope, just a bone stock 7m, currently runnin' it till it dies... still doin' general maintenance though, then i think i'ma go gte to 400 hp or so