v70 2.5P long term fuel trim

[MissSpentYouth]

Hi I have a 2004 2.5 Petrol non turbo v70 auto 140K miles

The orange engine light comes on and on Veda it reports long term fuel trim as the issue

If I check the long term fuel trim I get

area 1 1.22
area 2 1.23
area 3 1.06
area 4 to 8 1.0
data 1.22

If I reset the long term trim to 1.0 by disconnecting the battery for 5 minutes the car will hardly start and wont rev you can hardly drive it and then slowly slowly it will get itself together and eventually run fine. After a long trip once the long terms trims have got back to the above values the car runs fine.

However if it goes on a a long trip with lots of short stops it can then play up as above.

MAF reads 3.2 g/s at idle rising to 44 g/s at 5000 RPM tried changing it didn't make a difference

New fuel filter

Tried a smoke test all good just a small leak from the temp sensor in the air box, blocked it off and made no difference

Clamped of the evap pipe no differnce

Lambda reads 1.03 at idle and similar at revs once it has caught up

Fuel pressure reads 566KPa

If this was an old skool carburettored car I would say it was running weak and a tweak on the mixture screw to richen it up would sort it out

Any ideas bit stumped on this one

Plugs all good

Could it be low fuel pressure is 566 KPa about right ?

changed fuel pump relay no difference

[p7jox]

hi there it sounds like the same problem I am having with mine happens about once a week and I cant get to the bottom of it

the only thing that I notice about yours is the fuel pressure seams a bit high
566kpa is 5.66 bar of pressure, on my data list the recommended pressure is 3.8 bar

[MissSpentYouth]

just changed the fuel rail and injectors

Thought it had fixed it initially but no sadly not

Just ordered up a fuel pump and will try that

It does feel like it is running weak ....

If its not the pump and I have my doubts then I am stumped on this one

Checked the pressure against another car and it was near identical

[oragex]

I'm not familiar, what these numbers mean? Does it run rich?

I would think twice before replacing the fuel pump on these cars, at least don't throw away the old unit. I'm yet to have read about one that actually failed (other than aftermarket ones).

The fuel pressure on these non turbo sits around 55psi (I believe around 380kpa), yours indeed is quite high. I've already read about a similar issue, make sure the PEM is not corroded and has a clean connector and the FPS is not bad. Someone also had an issue with a ground to the fuel pump, but my memories get confuse at this point.

[MissSpentYouth]

Fuel pump finally arrived and is now fitted in the tank

A bit of a faff to get in in there to be sure

Happy to report the car is completely cured

Starts up lovely and I can clear the long term trims back to 1.0 and she runs great.

[oragex]

Did the removed pump look like an original Volvo one?