O2 Sensor Lean

Precisely.

It sure wasn't a bad air fuel ratio sensor though was it?

 

Interesting

 

Alls I'm saying is..

the last 10 toyotas (trucks, cars, vans) that came in with "stuck lean" or "slow response " codes got fixed with new sensors

Every fuel pressure issue ive ever seen (except for a Ford Ranger one time ) showed up on the hook with no codes.. either crank/start or it was completely undrivable, like wouldn't go up hills or accelerate

But thats been my experience..

carry on

 

See I knew that code was BS when I got it though because I actually very recently replaced the air fuel ratio sensor on that side for a separate reason, so I knew there was absolutely no way I had a stuck air fuel sensor.

Here's another one for you, recently had a 2015 Tacoma 4.0 in with a "air fuel ratio imbalance bank 2" gee, what could it be right? It could be a million things. Prior shop installed air fuel sensor on the wrong side, customer never replaced his copper spark plugs in 120,000 miles, and it had just not received any TLC at all. Smoke tested for vacuum leaks through multiple areas of entry to rule that out, Replaced plugs, swapped air fuel sensors to the correct side it needed to be on, swapped coils across banks, performed a compression test, cylinder leakage test, swapped in a known good computer to rule out bad software.. rechecked all data. Mind you we were in about 2.5 - 3 hours of diagnostic time at this point. Turns out the stupid truck was going lean on both banks which should have actually triggered a P0171 and P0174 code right? No sir.. removed fuel injectors to test and found a hot burn mark on the spray nozzle of two of them.. okay cool. Replaced them all, things cleaned up but it was still spiking lean intermittently (this one was incredibly hard to catch). Aha! The fuel pump is garbage. Replaced it, and after that, all lean activity ceased, the truck ran glass smooth, and I had the data to back that up. It sure wasn't a lean code for both banks though or some sort of fuel related code was it?

Another one I had, an early mid 2000s Corolla was throwing an EVAP purge solenoid code. After some intuitive testing, I replaced the PCM and the issue magically disappeared. Car ran a hell of a lot smoother too after that.

Moral of my ranting though is that Toyota throws symptom codes, not causality codes.

 

so not the whole "parts bin".. just half of it

 

I find it interesting, but the Toyota fuel pump issues I have seen have emanated from a myriad of ugly drivability issues, ranging from surging, to intermittent hard start issues, to suddenly dying (those last two were mine), to scorching injectors ultimately leading to codes but still seems to drive okay, to lacking power exclusively on inclines.

They are indeed hard to catch, but they say knowing is half the battle and given the broad range in which I have seen the failures emanate makes me a lot more privy to start inspecting that fuel pressure coupled with the short term and long term trims with a fine tooth comb now.

Anywho.. sorry OP. Just having a tech to tech moment here with my bro @b_r_o . Keep on doing the good man's work good sir!

 

Actually, no, the only part which we actually threw at it for test purposes was the PCM.

We swapped coils over from bank 1 over to bank 2 because I was hell-bent on not ordering one singular part until I was absolutely sure that I had the issue narrowed down to two possibilities. The air fuel sensors were swapped over banks as well and the spark plugs were replaced for maintenance purposes as well as potential cause of the issue purposes. So those two possibilities ended up being either PCM or injectors and since PCM is easier to get to and a cheaper alternative to pulling the intake to test injectors we opted for that first as I see more and more commonplace PCM failures or software glitch issues these days on newer cars.

 

I knew you were a tech when you said "replaced computer with known good.."

I always chuckled at how the trouble trees just casually toss that step out there

 

I know right. As if we just have a random 1991 Acura Legend computer just lying around in our shop at the time of testing.

 

I used to work at a wholesale auto auction. 75 acres of "known good" cars parked right outside the door, at least the ones that ran anyway..

There was some "borrowing" from time to time





Sorry for the thread jack OP! Gotta give em something to read tomorrow I guess

 

I'm sure he'll love the insight and general debauchery going on here. Hahaha. Typical TW crap with a real technical twist. These ain't your typical light bars, lifts, and tires sort of posts.

 

Turned out to be the air fuel sensor. $150 part and running like a top now.

 

Thanks for the update

Sorry about Rob and me hi-jacking the thread

 

No problem thanks for the help