Engine code help

[Steve-O]

Hey guys, well over the past two days, my GF's 91 FJ80 has been pulling 2 trouble codes. The first time I checked them, I thought it was a fluke, so I cleared the codes. But sure enough, they came back up a few hours later.

It came up with code 25, and code 26. Checking the FSM, code 25 is for "air-fuel ratio lean" and code 26 is for "air-fuel ratio rich" needless to say this threw me off a little bit.

I was hoping to really check it out this weekend, but I wanted to see if anyone has come up with this problem before.

The vehicle currently has:

205k miles on truck, motor was rebuilt at 200k
Two new O2 sensors (less than 5k)
Recalibrated fuel injectors (less than 5k)
fuel filter (less than 5k)
air filter (less than 5k)
I checked the air-flow meter when I rebuilt the motor, it was working fine at the time.

Any thoughts? Any help is much appreciated.
Thanks, Steve

 

[CJF]

Hey Steve,

This would be a great one for the 3FE list; we're kind of tech starved over there at the moment and going a little stir crazy.

Curtis

 

[JerryLX450]

Could be the purple thing maybe?

 

[Atticus]

On the FZJ-80, that problem can be, in addition to injector problems (which you likely don't have given the injector work you've done), a bad engine ground, or problems with the harness that runs over the manifold (it can get brittle over time and may need to be replaced). I had this problem for a while, and it just...went away. Or at least the thrown code did.

I know yours is a different model, but I would guess that the codes represent the same (basic) problems. Hope this helps.

Cheers,
Jay

 

[semlin]

I'd start with testing the o2 sensors and connections.

 

[Steve-O]

Thanks for the advice, when I rebuilt the motor, I did end up replaceing some of the harness wires, and a lot of the shielding. Other than that it seemed fine. Whats wierd is that the motor runs the same as it always did, or a least it seems that way.

I was going to test the O2 sensors this weekend, just to check, but they are brand new. All of the Connections are fine from what I can see, but I do have to do some more crawling around. The computer did not throw a bad 02 sensor code however.

Jerry, at least the truck says land cruiser on the back! Not
pink-pantius maximus aka lx450.

 

[Brentbba]

Could be the purple thing maybe?

x2

 

[Atticus]

Check the ground wire/strap?

 

[Steve-O]

x2

Yeah well.....

 

[Steve-O]

Check the ground wire/strap?

Grounds are good, I'll double check the rear one with the connector. I dont see how that could come undone though. I saw a post with similar problems on the birfiled list thing, I dont really understand how to read that stuff though. Seems that they never came to a conclusion, or if they did, they never posted it.

 

[Atticus]

The advice I've gotten about the harness was to clear the codes, start the engine and play with the harness. If the code came out as a result, then *bingo*.

Let me know what fixes this, since, again, my codes just went away.

Good luck. I'm through padding my post count.

 

[Brentbba]

Yeah well.....

If she likes it that's all that counts, not what any of us think.

 

[Steve-O]

The advice I've gotten about the harness was to clear the codes, start the engine and play with the harness. If the code came out as a result, then *bingo*.

Let me know what fixes this, since, again, my codes just went away.

Good luck. I'm through padding my post count.

Did you come up with the same codes though? 25 & 26?

 

[Steve-O]

If she likes it that's all that counts, not what any of us think.

Yeah she loves it, honestly she thinks its the best upgrade on her truck, right after sirius radio of course. And dont worry Brent, your not a , but you are a .

 

[JerryLX450]

Hey look i got engine code and color code

 

[Atticus]

Did you come up with the same codes though? 25 & 26?

Yup. At the same time, just like you did. That's why it makes sense to me that it is either a harness problem, or something wrong with the injectors. I may be the least mechanically-inclined person on this board, but it seems to me that you cannot have both a lean and rich condition simultaneously unless it is one of these four: electric problem causing a weird read, electronic problem causing a weird read, fuel delivery problem alternating between rich and lean, or predetermined code for a part needing replacement.

 

[Brentbba]

Yeah she loves it, honestly she thinks its the best upgrade on her truck, right after sirius radio of course. And dont worry Brent, your not a , but you are a .

LOL!!!! Hehehe

 

[Steve-O]

Yup. At the same time, just like you did. That's why it makes sense to me that it is either a harness problem, or something wrong with the injectors. I may be the least mechanically-inclined person on this board, but it seems to me that you cannot have both a lean and rich condition simultaneously unless it is one of these four: electric problem causing a weird read, electronic problem causing a weird read, fuel delivery problem alternating between rich and lean, or predetermined code for a part needing replacement.

Well my main thought behind it is that it must be running lean at one rpm range, and rich at another rpm range. It could be a wierd electrical reading, but usually the computer will pick that up (like a bad o2 sensor.) I will definately look over the wiring a bit more, the harness the runs over the engine is damn near impossible to get to, but I will see what I can do. Hopfully I'll have it fixed this weekend, I will definately post my results.

 

[powderpig]

Have you looked also at the FSM trouble shoot chart to see if any over lap between the two codes. That may also be a good thing to do. other wise I too would look at wiring. later robbie

 

[Steve-O]

Have you looked also at the FSM trouble shoot chart to see if any over lap between the two codes. That may also be a good thing to do. other wise I too would look at wiring. later robbie

Yeah there are a few different ones. Injector, injector circuit, fuel line pressure, air flow meter, and ECM.

I will be checking all of that this weekend, but was hoping to come accross a few people with the same problems, and possibly had definate fix.

Steve