Petrol Diagnostics

Back to Forum

Post a Response

Volvo V70 2.3 T B5234T3 2001 - Fault code P1171 system lean part load #

Posted by Ian Staples on June 17, 2010, 7:34 pm

Year of Manufacture *: 2001
Engine Size and Code *: B5234T3
( Optional) Fault Codes: P1171

This vehicle has P1171 - System too lean part load, yet drives perfectly well, even when the light comes on you don't feel or notice anything. Live data looks good. Ive recorded live data and reviewed it, cant see anything wrong other than the LTFT is up and down and steadily drifting towards being constantly 25% which is when the light comes on. Reset everything and LTFT goes back to 0%, drive for a while and same fault happens. Cant find an air leak. Each injector drops the engine revs the same amount.

Any ideas?

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by aidan birley <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2879' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 8:02 pm, in reply to "Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Aidan Birley

Hi

Possible issue with MAF ? can you scope it ?

Also careful check of breather hoses.

Cheers Aidan

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 9:09 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Peter Mutlow

Evening Ian,

What is the HO2 sensor doing and O2 reading might give an insight if it is running too lean. Agree with Aidan re MAF.

Rgds

Pete M

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 9:59 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Mark Carter

Hi Ian, what tests have you carried out on the induction side of things?
Have you checked the fuel pressure yet?
What is the AMM reading?
What is the post cat sensor reading?
What is the CO reading at the pipe? HTH

Regards Mark.

Modern cars, Its all wizardry and witchcraft

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 10:27 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Ian Staples

The MAF followed the throttle position and engine speed.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 10:38 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Ian Staples

Post HO2 (bank 1, sensor 2) reading stayed steady around 0.6v. Will do an O2 test tomorrow. MOT'd it today at the same time, CO% was 0.1 and falling nicely, Lambda was dead on 1, HC's were nice and low.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 10:42 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Ian Staples

Fuel pressure check tomorrow along with O2.

MAF reading from 4, up sharp to 70.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on June 17, 2010, 11:23 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Peter Mutlow

Nice one Ian. I note that the fault code stands for "Long term fuel trim - upper limit reached" Is it possible to scope the MAF? You can see any glitches better. O2 reading will be good tomorrow.

Regards

Pete M

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Alan Kane <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT5535' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 8:55 am, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Alan Kane - Administrator

Ian, take a look at the conditions under which the trims are drifting. If it is happening under load then that is when you need to test it. It may well be perfect under no load conditions.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Mark Carter <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 9:06 am, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Mark Carter

Hi Ian, you wrote,
>>>MAF reading from 4, up sharp to 70.<<<

What are you reading the air in? if it is Kg/h then it is to low, specs for that car at idle are 7-14 Kg/h. Possible air leak?

Without trying to teach you to suck eggs, when you carry out the fuel pressure tests please plot the findings against boost pressure so that we can see the relationship. HTH
Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Dave Harney <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 12:11 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Dave Harney

P1171 - ECM-261A Upper limit

Regards
Dave

You can trim a sheeps wool many times, but you can only fleece it once !

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 4:06 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Ian Staples

Ok, some good points there, thanks. After i got my fuel pressure tester back from another garage and fixed the couple of leaks they had created, i tested the following:

Fuel pressure at idle - 56 psi
Fuel holding pressure - 50 psi

Sorry, havent plotted fuel pressure against boost, i understand what you mean but i havent the equipment to record and plot that information. All i can say is the fuel pressure stayed quite steady as it boosted.

Then the O2 cell packed up on my gas analyser so just used another garages gas analyser, measured the following:

Gas readings at idle
HC - 45
Lambda - 1.01
CO% - 0.016
CO2% - 15.46
O2% - 0.24
NOx - -13ppm

Gas readings at fast idle
HC - 3
Lambda - 1.000
CO - 0.015
CO2 - 15.67
O2 - 0.03
NOx - -18ppm

As for the point about driving it and recording the readings, the recorded live data was done while driving. First it happened as soon as i started it up, reset everything, had to drive a few miles before it did it again, reset again, had to drive for quite a while before it did it again, reset again, flushed and changed the oil which it was also in for, cant get it to do it now. Customer said sometimes it would be a few miles, sometimes 30 miles, sometimes it would go weeks without coming on.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Ian Staples <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1121' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 4:15 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Ian Staples

Thanks for that quote from the volvo book. I do understand fuel trims. I can see my LTFT drifting towards 25 over time which is when the light comes on. I liked the probable causes, basically anything to do with engine then

.

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Dave Harney <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 4:44 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Dave Harney

Ian,
Wasn't trying to "teach" you anything about fuel trims, was merely trying to point you in the direction of where P1171 actually relates to !

Regards
Dave

You can trim a sheeps wool many times, but you can only fleece it once !

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by martin young <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT2736' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 6:26 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"

ian
have you checked the exhaust manifold/flexy front pipe for cracks slight blowing etc?
martin

Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on June 18, 2010, 11:54 pm, in reply to "Re: Volvo V70 - 2001 - 2.3T - P1171 system lean part load"
Peter Mutlow

Evening Mark,

Bit of a poser this one. Fuel pressure looks good and O2 is good. Like Mark, do not understand the MAF readings. If there are no air leaks in the breathing system etc then I would like to scope the MAF. Is it possible that the HO2 sensor is glitching?

I had something similar with a BMW a couple of weeks back and after resetting the DTC, I could sit and watch the graph of the STFT slowing rising until it reached the 25 point. already searched for an air leak but convinced that there was something still there, I pulled at every crankcase ventilation pipe I could find and one actually came away in my hand. It was not connected properly and it was the suction of the inlet manifold that kept it in place.

Maybe a long shot but worth another look.

Best of luck

Pete M

« Back to index

[ Petrol Diagnostics ]

Copyright © uk autotalk