P0171 fault code

[T5frankie]

Lean conditions on bank one

short term -2.8%
long term - 25%

this is getting very annoying now

replaced the fuel filter, maf sensor, had the injectors cleaned and still the problem persists
i don't think i have a vac leak as at idle the vacuum is at -20.9hg

any ideas please

[jdavis]

lambda faulty?

[daza-b]

What fuel pump is in? Maybe weakened pump? If its not a Walbro may be worth getting one?

[960kg]

A lot of owners get this code even with the Volvo T4 ........

You can read pages and pages of what they have done and have spent a fortune on parts and one chap even replaced his engine ...when he finally resolved the problem it was the 3rd post on his thread and he paid no attention to it!......it always, always, always comes back to the same thing...

You have fitted a new maybe, but crap cheap faulty MAF sensor......

Same old thing really Volvo`s do not like being fooled!!

http://www.volvoforums.org.uk/showthread.php?t=149799

If you have by chance fitted a new Volvo MAF or good known 2nd hand Volvo MAF then it will be 1st O2 Sensor whether 4.4 or ME7

[graemewelch]

scrap and buy a 2.4 t5. job done

[T5frankie]

A lot of owners get this code even with the Volvo T4 ........

You can read pages and pages of what they have done and have spent a fortune on parts and one chap even replaced his engine ...when he finally resolved the problem it was the 3rd post on his thread and he paid no attention to it!......it always, always, always comes back to the same thing...

You have fitted a new maybe, but crap cheap faulty MAF sensor.......full stop!!

Same old thing really Volvo`s do not like being fooled!!

http://www.volvoforums.org.uk/showthread.php?t=149799

its not the maf as i have just put a known bad maf on it and it produced a bad maf code as well as the other code

[960kg]

If you have by chance fitted a new Volvo MAF or good known 2nd hand Volvo MAF then it will be 1st O2 Sensor whether 4.4 or ME7

It is no good putting a known "bad MAF" as it will give a MAF code.......you have either put a cheap copy MAF on or it is the 1st O2 sensor as said....!....definite.

The old error codes are still stored until you have about 6 cold starts unless you have erased them or they are resolved otherwise they will be back......i sound blunt but just trying to help as i see it everywhere all the time...

What good MAF have you actually put on the motor to replace the old one??

You have to use Volvo or 2nd hand known good Volvo otherwise it will not like it!

[T5frankie]

If you have by chance fitted a new Volvo MAF or good known 2nd hand Volvo MAF then it will be 1st O2 Sensor whether 4.4 or ME7

It is no good putting a known "bad MAF" as it will give a MAF code.......you have either put a cheap copy MAF on or it is the 1st O2 sensor as said....!....definite.

The old error codes are still stored until you have about 6 cold starts unless you have erased them or they are resolved otherwise they will be back......i sound blunt but just trying to help as i see it everywhere all the time...

What good MAF have you actually put on the motor to replace the old one??

You have to use Volvo or 2nd hand known good Volvo otherwise it will not like it!

i have bought 2 2nd hand mafs, one was a bosch and the other a copy, the bosch one works fine as i put it on my 850r after that had a maf issue 2 weeks ago and it cured the problem, it runs sweet. tonight i put the bosch one on the v70 as i have also done the injectors and fuel filter and still got the po171 code, i cleared it but its still comes back instantly, i put the bosch maf back on the 850 and put the copy one back on the v70 and i got 2 fault codes, bad maf an po171, i have another maf coming in the post (2nd hand) why the hell are they so bloody expensive new? i will try that, next point of call will be pre cat lambda

[T5frankie]

scrap and buy a 2.4 t5. job done

too slow mate lol

[jdavis]

lambda faulty?

...?

[T5frankie]

...?

yeah next thing to check mate,

what's the easiest way of testing fuel pressure?

[960kg]

i have bought 2 2nd hand mafs, one was a bosch and the other a copy, the bosch one works fine as i put it on my 850r after that had a maf issue 2 weeks ago and it cured the problem, it runs sweet. tonight i put the bosch one on the v70 as i have also done the injectors and fuel filter and still got the po171 code, i cleared it but its still comes back instantly, i put the bosch maf back on the 850 and put the copy one back on the v70 and i got 2 fault codes, bad maf an po171, i have another maf coming in the post (2nd hand) why the hell are they so bloody expensive new? i will try that, next point of call will be pre cat lambda

Frankie, when you spend all that time and money on your motor and you want the best from it it is clearly a fools paradise not to buy MAF`s new from Volvo, yes, they are expensive but the whole engine and ECU relies only on the MAF...which is clearly why any induction mods that are done the MAF will measure the air and WOW! ..........it is as simple as that.....

If you don`t fit new with such an important part you will chase your tail forever as you don`t know what to replace next!!


Just read your post again......as you have done so many swops about just run the thing for 6 cold starts as an example and see if the error code goes...

We have adapting ECU`s and you are not giving it a chance to adapt correctly as you are changing the hardware all the time which is a no ...go.

[Dangerous Dave]

Wow, 25%!! think that is the max limit set in the ecu.

[T5frankie]

Frankie, when you spend all that time and money on your motor and you want the best from it it is clearly a fools paradise not to buy MAF`s new from Volvo, yes, they are expensive but the whole engine and ECU relies only on the MAF...which is clearly why any induction mods that are done the MAF will measure the air and WOW! ..........it is as simple as that.....

If you don`t fit new with such an important part you will chase your tail forever as you don`t know what to replace next!!

understandable but this isnt for my 850r its for the v70r, which i got it with a maf problem, i replaced the maf all good for 200 miles now this problem different code, i hav.nt totally ruled out the maf is the culprit, but its xmas and i have 6 kids to provide for so have no dosh to be spending on new mafs

[T5frankie]

Wow, 25%!! think that is the max limit set in the ecu.

yeah it's letting me have 4 psi lol

[Dangerous Dave]

This the one you have just put the remap on?

[T5frankie]

This the one you have just put the remap on?

no mate, but i have put a mapped ecu in since i bought it, but i have tried both and still the same

[AndysR]

New Bosch MAF is around £140 plus vat ish, same as the Volvo boxed and supplied one, that's not expensive when you think of the job it has to do.

If it's running lean perhaps you've got a dicky injector, try swapping the injector rail from the 850 and see if the fault goes.

[T5frankie]

New Bosch MAF is around £140 plus vat ish, same as the Volvo boxed and supplied one, that's not expensive when you think of the job it has to do.

If it's running lean perhaps you've got a dicky injector, try swapping the injector rail from the 850 and see if the fault goes.

I've just had them cleaned andy

[Brett855tdi]

What are your afrs like during idle?
Mine yesterday started running mega rich (about12:1) to the point it wont even idle
If i disconnect the maf it runs ok but really lean when to try and drive with any sort of pace and cuts the fuel it you were to put your foot half way down.
Does this mean ive got a maf prob? i scanned it but only after i had unplugged it and i got fault, maf low voltage reading. so i dont if if that because i unplugged it or cuz of a fault.
I just put the 19t on the other day but it was fine for a day, but only after cleaning the air filter and reconnecting the pcv has it done this.
Sorry to hijack frankie.. was thinking we might be in the same boat... about to go and plug it back in and clear the code and go for a cold start see what happens