Fault Code P0088 - Fuel Rail Presure Exceeded

[In Reverse]

Hi new to this forum and wandering if anybody can assist re an ongoing Engine System Service Warning fault on my 05 D5 AWD SE Auto 163bhp.

During harder acceleration the car occasionally went into limp mode at higher revs (kick down at 3500rpm+), but seemed to clear itself and return to normal once I lifted off. I took it to Volvo Belfast who said it could be a number of things from Fuel pump to turbo, but they would probably start by changing air flow meter.

Obviously not happy with this 'cover all' diagnosis I took it to an independent who found fault code P-0088 Fuel Rail Pressure exceeded. He was able to say from freeze frame that at 91% of throttle, fuel pressure reached 160kpi, which sent car into limp mode.

His initial thoughts were injectors leaking (over 100k miles on my car) leading to the pump working too hard before going into limp. However he removed injectors and sent to a specialist who said they were fine. He then changed fuel pressure sensor and the car semed fine, and even seemed to acelerate a little smoother.

A week later and the fault has re appeared. Before going back to him I'd be keen to hear any views.

[1HCC]

I had exactly the same, two causes, oil cooler was split, only opened up on excelleration but not always, had this fixed (common fault) and fix problem for a few drives, then it returned and it turned out the fuel filter in the tank ( i believe) was clogged, despite a fsh this was stamped 04, never been changed, this was cheap £40.00, been great every since, my faults were identicle to yours, i would start at the cheap end i.e fuel filters

[In Reverse]

Thanks for that advice, I had read about the filter elsewhere so will get a look at it.

Does the split oil cooler leave a mess under car/on engine undertray/or engine bay. My car is regularly valeted and as such engine bay looks as new so would notice any leaks etc. I'd definately be keen to check the oil cooler.

Are there any other visible signs or easy ways to check?

[Lancee]

If you are absolutely sure the intercooler (not oil cooler) and pipework is sound, 1 change the fuel filter as already planned (relatively cheap). 2 clean out the EGR mixer pipework as if it's dirty, and yours at 100,000 miles could be well be filthy, it can seriously restrict the inlet of air (free). 3 replace the rubber turbo inlet pipe (approx £55 for the part from Volvo), this pipe goes soft and collapses inwards with the suction on full acceleration. IMHO any or all of these could cause your problem. let us all know if this works (or not!)

[In Reverse]

Perfect timing.

Just in from the garage after removing and cleaning egr valve and removing and checking the turbo pipe which seemed fine. The EGR was also relatively clear - although my car had a new engine last year/30k ago fitted by Volvo after they messed up a cam belt change.

Got a new genuine fuel filter on Saturday, but didnt get it fitted. Had a quick look and wasnt sure how to. Its booked back into my indy mechanic tomorrow anyway so will get himto do filter.

I had originally thought it was injectors after leak off test appeared to show excessive leak off from 2, but when taken out and to specialist to check he said they were well within tolerance levels(?!?).

Mechanic then changed the fuel sensor that is attached to the high pressure pump and although my wife, who now uses the car more than me, thinks it is smoother, its still going into limp mode in kick down at around 4k rpm.

Hoping the filter will sort it, mechanic suggests trying the fuel regulator thats attached to the fuel rail. Starting to feel like an expensive fishing trip.

[Lancee]

If the new filter proves not to be the solution I have seen on the forum about the in tank fuel pump causing this problem, do a search, after that good luck to you and let us all know how you fare !!!!

[grass hopper]

had a few cars with this code a few years ago,sure there was a ECM software upgrade for this.

worth checking with the dealer if its got the latest software.

[grass hopper]

Originally Posted by Lancee

If the new filter proves not to be the solution I have seen on the forum about the in tank fuel pump causing this problem, do a search, after that good luck to you and let us all know how you fare !!!!

the in tank pump is only low pressure and could not cause the high pressure fuel rail to exceed pressure.

[In Reverse]

Thanks for that. I've not much faith in the dealers.

I got it back from the independent mechanic tonight after he'd changed the fuel filter and cleaned out the recently fitted fuel pressure valve.

It does now seem to drive OK and revs to 3500-4000 on kick down without the warning light/limp mode coming on, although I was slightly apprehensive of driving it like a hooligan. I'll monitor it over next few days.

Worryingly however is that there appeared to be small metallic filings in the fuel when he changed the filter. Not sure if these had been lying since the old engine expired (cam belt failure 35k/1yr ago), or is it coming from a failing high pressure pump.

Any ideas? Would this have caused the pump to exceed pressure, is the pump worn out and returning these filings to the tank/filter? If so can the high pressure pump be reconditioned or overhauled. How much would a new one be?

[In Reverse]

I think I've got it sorted.

Changed the fuel filter and cleaned out fuel lines, and touch wood, 250 miles later with lots of kick-downs and car revs freely, up to 3500-4000rpm, and no limp mode.

Hopefully this has sorted my problems.

Cheers for all the advice and guidance.