Lean bank 2 - CVPI

[-Matt-]

Need help on an on going issue with my wife's CVPI.

Spontaneous bucking when driving (feels like a lack of fuel or COP issue)

Issue can be gone for days, then come back in force.

Got it to throw a code. 0172 lean bank 2


Maintenance that has been done thus far:
-Current checked all of the COP's, replaced a bad #5 cylinder COP (thought it was the issue, but symptoms came back) All other COP's checked good
-Changed and gap all of the plugs
-New fuel filter and oil change


Can never get it to cause an issue when i have the "ford" computer on her.

Getting frustrating, please help

[SpartaPerformance]

What "Ford" computer are you using? If you have an IDS like dealers use you can run a power balance test and/or injector flow test to find the issue.

[-Matt-]

What "Ford" computer are you using? If you have an IDS like dealers use you can run a power balance test and/or injector flow test to find the issue.

We did both on the IDS with no seen issues (because we couldnt get it to recur)

[Billy]

Are all 4 narrowband o2 sensors giving good a/f readings?

[NATEHAWK]

That cylinder that gave you problems check for a loss of compression around the spark plugs. You may have one that's about to blow out. My 01 CVPI had a similar issue.

[-Matt-]

Are all 4 narrowband o2 sensors giving good a/f readings?

They seem to be


That cylinder that gave you problems check for a loss of compression around the spark plugs. You may have one that's about to blow out. My 01 CVPI had a similar issue.

That will be hard to test, but i did put brand new plugs w/ anti-seize in all cylinders.

[justbob]

Sounds like a moisture related problem.

[-Matt-]

Sounds like a moisture related problem.


Your a moisture related problem.


But no really, it does it dry and wet and it doesnt do it in the worst rain either its very spontaneous

[cvpiftw]

How are the cats? It could be a clogged cat and the o2 is acting funky due to temp and air pressure. I have seen it happen on a few squads in the shop. Another idea would be to do a compression test anyway.

If you have a IDS cable and laptop I would make sure to double check that the PCM has the correct updated revision in it and scan for pending and related coded. Do the monitors ready otherwise?
If you have an injector machine it might be smart to throw them in there anyway just to double check. I would be checking the resistance in all the injectors if your going this deep to diagnose the issue.

[-Matt-]

How are the cats? It could be a clogged cat and the o2 is acting funky due to temp and air pressure. I have seen it happen on a few squads in the shop. Another idea would be to do a compression test anyway.

If you have a IDS cable and laptop I would make sure to double check that the PCM has the correct updated revision in it and scan for pending and related coded. Do the monitors ready otherwise?


How would a bad o2 reading effect a lean bank situation? At that point it should throw a bad/off o2 code and not try and lean out a bank.

We checked all codes past and related and even did a PCM reset when we changed the #5 COP to try and speed up the re-learn process. The problem went away for hundreds of miles but came back.

[justbob]

Your a moisture related problem.




Yeah I am! When you dream about my sweet azz... :D

[cvpiftw]

How would a bad o2 reading effect a lean bank situation? At that point it should throw a bad/off o2 code and not try and lean out a bank.

We checked all codes past and related and even did a PCM reset when we changed the #5 COP to try and speed up the re-learn process. The problem went away for hundreds of miles but came back.
True, but you NEVER know what a bad o2 or pressure on a o2 can do. If there is excessive pressure I know all types of wierd **** can happen with the sensor.

The car could be compensating for a bad o2 and throw the code as its compensating. If it went away for a few hundred miles and came back i wonder if its throwing it off because it cant complete the drive cycle or something drivecycle related.

The other thing that I am wondering about is the bucking. If it was bucking still after replacing the bad COP, I wonder if it is an intermittently faulty o2 and just not acting right when you want it to. Did you check A/F when it was bucking?

Also might be ideal to try different fuel if you consistently use the same station, thats a HUGE longshot but depending on where you live i have seen some issues where ethanol will separate and go into higher concentrations and make a VERY high concentration of ethanol to gas. Like I said, that is a HUGE longshot but just trying to cover all bases.

[cvpiftw]

Yeah I am! When you dream about my sweet azz... :D
I think i just puked.

[guspech750]

Yeah I am! When you dream about my sweet azz... :D

Mmmmmmm. Bobs ass!! Mmmmmmmmmmmmmmmmmm


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[tbone]

Mmmmmmm. Bobs ass!! Mmmmmmmmmmmmmmmmmm


Sent from my iPhone
Eaton Swap + 4.10's = Wreeeeeeeeeedom!!

Stock up for Louisville!!!

http://img.tapatalk.com/6390aaad-698f-dc76.jpg

[-Matt-]

True, but you NEVER know what a bad o2 or pressure on a o2 can do. If there is excessive pressure I know all types of wierd **** can happen with the sensor.

The car could be compensating for a bad o2 and throw the code as its compensating. If it went away for a few hundred miles and came back i wonder if its throwing it off because it cant complete the drive cycle or something drivecycle related.

The other thing that I am wondering about is the bucking. If it was bucking still after replacing the bad COP, I wonder if it is an intermittently faulty o2 and just not acting right when you want it to. Did you check A/F when it was bucking?

Also might be ideal to try different fuel if you consistently use the same station, thats a HUGE longshot but depending on where you live i have seen some issues where ethanol will separate and go into higher concentrations and make a VERY high concentration of ethanol to gas. Like I said, that is a HUGE longshot but just trying to cover all bases.


I haven't been able to get it to fail on IDS

In my opinion, if the o2 was intermittently faulting enough to produce a lean bank then it should throw a related o2 code.

It cant be the same fuel because we recently took her on a cross-country and gassed at multiple different stations and the issue was still intermitent

[justbob]

Maybe some crap in the tank passing thru the filter and injectors? Doesn't take much at all. Even a fuel pump on its way out could be intermittely causing pressure drop. Have you datalogged FPDC?

[yjmud]

did you look for an air leak?