Stuttering, Spluttering, Holding Back = Frustrating!!!

[ICF]

I have an ex plod s60. I bought it with a knackered turbo, sourced a k24 (as fitted previously) and fitted that.

Have now got it mot'd but it splutters, jerks and basically holds back on hard acceleration. Its ok low down in the rev range and will keep a constant high speed, just won't accelerate smoothly.

So far i've fitted a new front lambda sensor (came up on diag and cured high co2 emissions)
replaced the fuel filter
and fitted a new fuel pressure sensor.

The delphi diag software i've used comes up with fuel pressure low, hence the fps, but changing that has made no difference. I dont think its a misfiring problem as it start and runs perfect lower down the revs??

Anyone got any ideas?

The only thing I can think of now is that the fuel pumps knackered? I believe you test the fuel pressure with the scharader valve on the fuel rail? I dont have a guage (except a tyre pressure guage) to measure it with. Should I try measuring the pressure and what should it be?

thanks in advance

[stribo]

I believe the pressure should be 3.8 bar, I'm sure someone will confirm shortly.

[ICF]

Im thinking I might try some new plugs just to rule that out then go from there?

[silverhorse]

Im thinking I might try some new plugs just to rule that out then go from there?

Bit pricey to replace them on the off chance. Get them out and have a good look. You will know if they are knackered.

[p fandango]

I believe the pressure should be 3.8 bar, I'm sure someone will confirm shortly.
yes

[PHIL V70R]

have you replaced the bcs....

[ICF]

No. Bcs? Boost control solonoid?

Should I? Would it not show on the engine codes if there was a boost problem?

[M-R-P]

Split boost pipe could cause this effect too. Worth taking them all off, examining them and refitting with new jubilee clips.

[LeeT5]

if the fuel pump was knackered the car wouldn't run let alone accelerate.

As you have changed the FPS and it made no difference....i assume you cleared the codes after fitting and before starting the engine? What codes you getting now then??

Check condition of oil, if in doubt do an oil change as this can affect the VVT.

Also, Plugs are often underestimated. They can make an enormous difference, especially on a car engine when its under load, which your fault seems to rear its ugly head when under load. If your not getting any codes then i would replace the plugs. Check all vac hoses. Faulty BCS solenoid won't cause the symptoms your getting, especially juddering. A FPS fault will thou! Replace the Fuel filter too.

Other faulty components that cause the symptoms you describe will also include:

Crank shaft sensor
Cam shaft sensor
Ignition coil
Spark plugs
Water/damp on any HT components
faulty VVT/dirty oil
Faulty injector (very rare)

For the record, a misfire can occur at idle or under load depending on the amount of resistance in the HT. Make sure engine is clean and dry, check for wasted spark in the dark with no torch and engine running. Have somebody throttle the engine and look for 'tracking' especially around the ignition coils. You will of course have to refit the OTE pipe but leave covers off.

Lots to check and can be a swine to fix. Good luck.

[ICF]

Ok so I've measured fuel pressure.

On initial start up it is just under 3.8 bar which I believe is correct then drops to 3 bar on idle.

On reving it fluctuates slightly but stays at or around 3bar

Does this mean either my pump is weak or the fpr is §§§§§§ed?

Is the fpr in the tank?

[deathrider311271]

do some live data mate and check what readings your getting from the MAF and what spark advance your getting. As for BCS code it wont come up or it certainly doesnt on a P1 ME7 car

[960kg]

Jerkiness or misfiring on a turbo with boost is 99% ignition.....

I would start with the cheapest parts eg: Volvo recommened Spark Plugs...

[960kg]

Ok so I've measured fuel pressure.

On initial start up it is just under 3.8 bar which I believe is correct then drops to 3 bar on idle.

On reving it fluctuates slightly but stays at or around 3bar

Does this mean either my pump is weak or the fpr is §§§§§§ed?

Is the fpr in the tank?

FPR will give you problems on hot starts!!

[ICF]

Jerkiness or misfiring on a turbo with boost is 99% ignition.....

I would start with the cheapest parts eg: Volvo recommened Spark Plugs...

I've fitted a full set of Volvo plugs...no difference

[JamesT5]

Possibly coil packs or ETM from what I've learned but also could be the MAF.

[ICF]

Finally fixed the problem!!!!

Just thought I better update the thread.

It was the fuel pick up on the pumps that was gummed up with brown sludge. I cleaned off the filter and the swirl pot, put it back together and now its perfect, pulls hard through all the gears.

Only wasted £120 on parts when it was a free fix!! We live and we learn.

[V70 Graham]

Glad it's fixed, don't be too hard on yourself, the new plugs and fuel filter etc will only have improved things.