Omega has driven for a week (200miles)  :) with no problems or mil light,today the mil light (not spanner light) came on,still driving like a gem,read code to be P0170 fuel trim bank 1,cleared ok, i know what the code means but why is it coming up? there are no vacuum leaks or exhaust leaks,car has had new oxygen sensors,maf sensor and cam sensor (all genuine vaux) >:(

i had the exact same problem with mine,i changed
cam sensor
air flow meter
both lambda sensors
new exhaust manifold and gasket,as old one had cracked
new rocker cover gasket,as oil had soaked the plug wells.
then eventually,fitted a new cat,
cleaned out breathers and throttle
a very expensive problem solved.

cheers for that,ive done everything you have except the cat! shes been ok today! ::)

I'm not far away, and can read live data, birdman ... :y

mil light on again >:( code P0170,freeze frame data as follows
DTCFFRZF  P0170
FUELSYS1   CL
FUEL SYS2  N/A
LOAD-PCT(%)  44.3
ETC(.C)  88
SHRTFT1(%)  14.1
LONGFT1(%)  10.2
RPM  2251
VSS(KM/H) 48

Can anyone tell what is causing this code to come up.I can find no vacuum leaks!! :D

does anybody know if the fuel trims are high on my previous post,if so what causes it?,ive tried everything!!!! :'(

birdman wrote on 18. Aug 2011 at 19:52:

mil light on again >:( code P0170,freeze frame data as follows DTCFFRZF  P0170 FUELSYS1   CL FUEL SYS2  N/A LOAD-PCT(%)  44.3 ETC(.C)  88 SHRTFT1(%)  14.1 LONGFT1(%)  10.2 RPM  2251 VSS(KM/H) 48 Can anyone tell what is causing this code to come up.I can find no vacuum leaks!! :D

No.
SHoRT term Fuel Trim 14.1%
LONG term Fuel Trim   10.2%

... Are missing the all important + or - to indicate rich or lean trim level. It's the long term figure that's important, as it takes an average over a period.

As I understand it, if it was +10.2% for example, that would mean it was adding injector duration due to a lean condition. And obviously vice versa for a minus figure.

Although coming from a v engine, and seeing the light tripped from + or - 24% and above, those figures don't look massively ott imle...

but you really need some input from one of the tech2 guys on here tbh... :-/

thanks,it doesnt show + or - on my Autel MS509,but assume its + as sometimes the short term ft shows a minus sign.

birdman wrote on 22. Aug 2011 at 22:22:

thanks,it doesnt show + or - on my Autel MS509,but assume its + as sometimes the short term ft shows a minus sign.

If that's the case then it's adding fuel as the lambda is seeing a lean condition.

First thought Air leak, but there are non you say...? Tried the carb cleaner trick? Does it hunt?

ive had a really good look around and all vac pipes seem sound,ive cleaned out the throttle body,when you put your foot down it does seem to be hesitant,idles perfect!it had a genuine maf and both lambda sensors last year fitted by previous owner. :(

Could be anywhere from post Maf.

I suffered this problem on my 2.2 petrol for a long time ... im trying to find the posts i had on it but the search thing is not finding them .
Live data readings would be a real bonus if you can find someone with Tech II or Opcom etc and i could compare them with my current readings ( no mil lit ) to see whats different .
Im 99% positive mine was cured with new maf however ,  but you say you have changed it so id be interested in comparing live data .
HTH

Hi all,
Fuel trim fault P0170 still activating randomly,freeze frame always shows short term fuel trim as 14.1% and long term fuel trim as 10.2%,its driving me mad and running out of ideas! does anyone have any ideas? >:(

have you refuelled since problem started or maybe just before problem started (and have you refuelled since??)

ive refuelled a number of times,just changed the fuel filter which looked like it had never been changed! 140k too!

As said, you're going to have this problem when the ECU is trying to correct the fuelling too far based on what it sees from the Lambda sensor.

3 basic reasons why this might happen:

The ECU is calculating the required fuelling based on duff information.

The fuel calculated by the ECU is fine, but that's not what the engine is actually getting.

The Lambda sensor is giving you an incorrect reading of the actual mixture, forcing the ECU to compensate unnecessarily.


In the first case, the major inputs are engine speed, coolant temperature and air mass entering the engine. Engine speed is from the crank sensor and if it wasn't working you'd have bigger problems. Coolant temperature and air mass are possibilities, so it's always prudent to check these look plausible in the live data. An unmetered leak of air into the intake will also cause a false air mass reading so check the breather pipes and intake ducting for leaks.

The second case.. Low fuel pressure due to failing fuel pump, clogged fuel filter, fuel pressure regulator, perhaps injectors. These aren't common problems. Poorly mapped or just poorly LPG systems are.

In the third case, a blowing exhaust, particularly upstream of the lambda sensor, will cause it to read incorrectly, as will a misfire, although with other more obvious symptoms. A failing lambda sensor can also throw out the fuelling, although the ECU will normally flag it as bad before it does, or at least there'll be codes relating to slow response.

A cat problem won't cause fuel trim problems, or at least not unless it's so clogged that it is affecting the fuel mixture.

I had the P0170 a couple of times just before my crank sensor packed up.

...forgot to add that after changing it P0170 did not recur...you may remember this Kevin from 18 months ago

Call me Victor Meldrew but "I don't belive it!"

I am 200miles from Leeds in the beautiful Galloway forest and the Omega has been peefect until...yesterday whilst idling at the camp site, the EML came on. Still ran fine after no probs at all, but then today at the most southern point in Scotland where only sea can be seen from most angles, the car would not start.
Long story slightly shorter, AA sub contractor came out, very nice chap, put the diagnostic reader on the car and showed this code. Eventually got it started and has been fine ever since.
Bit concerned as had a thread only last week about the car stalling on idle, and worried it might be the crank sensor. I have a 200mile journey tomorrow, anything I can do to get back?

Cheers

crank sensor is favourite culprit

if i turn the heating system/vent control to "off" i get no mil light for days,as soon as you switch it on and the blower activates the mil light comes on P0170! driving me around the bend,i cannot find any air leaks,i bet no ones every heard of it! :D

birdman wrote on 30. Aug 2011 at 21:25:

if i turn the heating system/vent control to "off" i get no mil light for days,as soon as you switch it on and the blower activates the mil light comes on P0170! driving me around the bend,i cannot find any air leaks,i bet no ones every heard of it! :D

There are 2 vaccuum solenoids up behind the glove box, aone controls a vac feed to the HBV. one does the "recirc" function. I wonder if you have a vac pipe either off or damaged in theses areas ?? and the vac leak is only apparent when these funtions are "active" ... ie "downstream" of the vac solenoids ??

Clutching at straws I know .......  :(

thanks i will check,i was unaware of these vac pipes,do all the air divert flaps operate off the vac system aswell? you can hear things wiring away when you switch off the ignition

birdman wrote on 30. Aug 2011 at 21:38:

thanks i will check,i was unaware of these vac pipes,do all the air divert flaps operate off the vac system aswell? you can hear things wiring away when you switch off the ignition

AFAIK the vac only operates the HBV and the Recirc flap, all the other air valves are electric motors.

thanks very much,good info!  :y