Chuki

I get these 2 codes, which indicate a rich condition, and the other a lean condition.

I only get it when with my A/C on, and I'm on the freeway. In town and A/C everything is fine. But when I jump on the freeway with the A/C running I get the CEL. If I clear it keep the A/C off everything is ship shape.

Any ideas?

Chuki

Blah Nobody? Surely I'm not the only one who's had this problem?

toyo22r

Thats odd that its occuring only when AC is on... Your sure its related? When i had these codes popping up, I would clear the ECU and it would take just about exactly 50-55 miles of driving, cumulative, to get the CEL to come on.

Having the injectors cleaned by cruzin pref. did the trick. Funny thing was, they were not really that clogged, according to the 'before' flow tests. A Toyota tech told me it didnt take much deviation at all to get the lean and rich codes tripped.

toyo22r@hotmail.com
95 4Runner
St. Louis

Chuki

I'm 99% positive its when the A/C is on... Yesterday I spent 45 minutes crusing up and down the freeway. Without A/C on the light would never come on, turn A/C on after about a mile it would come on.

Kinda hot now but when it cools this evening, I'm going to start checking vacuum lines. My Idle Up solenoid for the A/C might have a vacuum leak.

Chuki

Some more info to add to the equation. A/C doesn't seem to be the culprit. It seems to be slightly related to ambient air temp...

Yesterday when I was trying to find it out. The outside air temp wasn't quite so hot, I'd guess High 80s, the only time I'd get code 25, 26 is when I would turn the A/C on. Today outside airtemp was approx mid to high 90s. No A/C light came on, checked codes, 25 , 26. So on my way home the outside air temp is probably mid 80s maybe lower. No A/C light never came on, A/C on light comes on.

So it seems to be somewhat related to the ambient airtemp. Also I had my uncle kinda look at it, to get some other input. He didn't really know since it runs just fine, just gets kinda crappy gasmileage, he said though its running way rich. My exhaust pipe is very black sooty.

So theres some more info. I don't really know what to pin it on.

THe reason I think the A/C helps trip it is, when I use A/C its of course adding more heat to the engine compartment, and I have modifed my air intake. I removed the shroud from behind the headlight and cut the bottom of my airfilter housing out.

Chuki

No one? This thing is driving me nuts.

Chuki

Drove probably a total of 35-40 miles about 25 of that on the freeway. No light or anything, A/C on or off didn't make a diffrence at all.

So I'm thinking more and likely its my o2 sensor, or a combo of a few things.

I plan on testing my Coldstart injector, ECU Temp sensor, and finding someone local possibly who can clean my injectors.

I would assume if my o2 sensor was indeed bad I would get a code 21 or 25,26 pretty much consistant or at least predictable... I'm thinking its something the ECU is able to compensate for most of the time, but during extremes (which seem to be hot extremes outside temp wise) it can't quite do it.

EXTREMECREATION

I had almost the same problem but it came on after 50 miles of driving with or without the a/c. Backprobed my o2 sensor and found that it was switching like it was suppose to..did a compression check and found that the #4 cylinder was 40psi low on compression compared to the other ones..Finally I did a cylinder leak down test and found my valves were leaking..After pulling the heads off I found both the intake and exaust valves on #4 were bad..That was why it was setting a code #25 & #26 for both rich and lean..My suggestion is to do a compression test and if one cylinder is low then do a cylinder leak down test..But first backprobe you o2 sensor..Checking your valve clearance according to manufactures recommendation is very important because if you dont then the valves get tight and they start to burn and leak..

Chuki

I'll have to do that, been wanting to anyways.

Although I would imagine if I indeed have that I would assume it wouldn't run all that well... The runs damn great, cept for a slight rough idle which I'm pin pointing on the injectors since it isn't all that rough anyway.

Chuki

Did a compression check, it did show me my engine isn't in the greatest of health but I already knew that...

Here's the results

#1) 147 after oil 165
#2) 161 after oil 170
#3) 175
#4) 170
#5) 176
#6) 174

They're all pretty much close to within spec, cept for #1 which is where my headgasket blew last time, but adding oil brought it up to spec so that shows I don't have any leaks other then past the rings.

So with that in mind would that cause a code 25,26?

Chuki

Well I tested the coolant temp sensor, everything there tested out just fine, While back behind the intake I noticed a vacumm line for my TVV wasn't hooked up which routes to the throttlebody, hooked that up, and took it for a test drive, power, torque and overall drivability improved 10 fold, before even doing 60 it'd struggle a little on the freeway. Not today cruised it just fine, on all the small hills kept right on truckin.

I also had thought I cured my 25, 26 code troubles... Well I decided to hit a decent grade hill just to see what kinda power, well maintain 60-65mph, using about 60-75% throttle to keep speed, once I start getting to the top I'd let off the gas and that triggered the light.

So the light seems to be triggered traveling approx 2500RPM+ with approx 3/4 throttle, for a period of time I would give it 2+ Minutes, once you let up on the throttle that triggers it.

EXTREMECREATION

Well the compression readings look fine which is good news..#1 is a little low but a 10percent variation between cyclinders are fine..You might have a vacuum leak..try spraying some carb/brake clean around the manifold and vacuum hoses to see if there are any leaks..next try checking the MassAirFlow sensor..pop off the intake and stick you finger into the MAF and push the flap door, it should sping back once you let go..if not then you have a bad MassAirFlow meter..if everything checks ok then i'd say backprobe your oxygen sensor..you might have a lazy o2..

Chuki

I've checked all that...

I fixed the one vacumm leak with TVV and EVAP system, and that really cured my rough idle, and weak power, and I'm sure had something to do with my poor gas mileage...

All these things you've said I've already checked they all check out fine.

I'm gonna hook up a voltmeter to my Diagnostic port for my o2 sensor and route some wires into the cab and see what happens with my o2 sensor when I put a load on it.

Chuki

Have you backprobed an o2 sensor before?

Following the FSM how to, I jumper TE1 and E1 to get into diagnostics, run the engine at 2500RPM to warm up the sensor, then run for 90secs and 2500RPM and count how many times the voltage changes.

Not sure what the voltage should be, but from reading it at the diagnostic port it was around .134-8 and would only change the longer I drove it or ran the engine. Never flucuated or anything.