General: S80 D5 auto fuel rail pressure too high

[toadywoad]

Hello all

I've a 2003 S8 D5 auto that has just had a replacement (used) engine fitted (main block and head) following major oil leaks.

The car with the old engine ran fine (despite the oil issue) however since all the original bits are now on the 'new' engine it has a serious lack of power especially from standing starts and the usual service error message for a second is displayed on kickdown and the car 'dies' (feels like fuel just stops!) for a second when accelerating hard in the higher gears, then it carries on.

The fault code is something like 2501 (from memory) and the mechanic who fitted it all says this is a high fuel rail pressure error, but despite his best efforts he can't trace any faulty components.

Any ideas on a remedy, as although I'm driving it, the lack of power is very annoying!

[Bernard333]

I have a similar fault on my 2003 V70 D5 and it does sound like a fuel delivery problem but you never know , I have had a couple of garages look at it and they have not come to a conclusion and even though mine appears to go into limp mode when it loses power when you shut down and restart the engine everything goes back to normal and there have been no fault codes so I am trying to find my fault by ruling out the obvious easy to do items which so far are 1 Fuel filter - easy to change yourself and dosnt cost much . 2 Fuel pump should be giving up to 2 bar on load but isnt needed all the time unless the engine mounted injection pump cant cope on acceleration or starting but you can get an inline pressure tester for £30 or less , its messy but easy to connect in next to the main injection pump at least doing that check you know there is fuel delivery up to the main pump at some pressure . 3 Turbo wastgate sticking intermittantly 4 Intercooler burst or one of the black rubber pipes split 5 MAF unit - disconnected mine , test drive and then reconnected and seems that did something as car running fine for past few days so could be I had a bad electrical connection but I dont think the problem can be so simple . A more experienced forum member advised that the high pressure pumps on D5s dont normally fail so I dont suspect that anymore . Front oxygen sensor on the cat am planning to do a flame test and measure the voltage but concerned that may knacker it completely but at 128k miles it may not have much life in it anyway so nothing to lose there but its a pain to get the sensor off and mine is so tight I am needing a special tool to avoid damage . There are loads of other possibilities of course and it seems that just having the diagnostic gear doesnt always pinpoint the failed component as can be seen from the many posts about main dealers being unable to resolve problems , you need someone with good training and experience to interpret the output correctly .

[toadywoad]

Blimey thats a comprehensive list of stuff!

Its had a load of new rubber pipes on it during the engine fitting and I originally suspected the MAF sensor after reading otherVolvo threads, but the mechanic thinks thats ok although I might try to disconnect it and see. Will get it booked into my local Volvo service centre to see if they can offer any advice aswell (they have actually been quite good in the past although I didn't use them for the engine transplant due to high labour costs!)

[hobbyhorse]

As Bernard mentions change the fuel filter. I would do this first before anything else as it gives some strange codes / symptoms. It's 20 quid well spent

[toadywoad]

Forgot to mention that its got a brand new fuel filter on it - that was the first thing the mechanic put on when it was playing up - didn't make any difference though!
I wondered if it may have been some dirt clogging up a component when it was put back together, but the mechanic thinks otherwise, but is still at a loss to find out what!