unstable fuel pressure

[tryagain12]

Right, this is a Relay, but the 2.2 100 PUMA engine.
Quick question is should there be rail pressure with ignition on, system primed, engine off, or does it only build once I start cranking the engine ?
I know it sound daft but still working out components/relation/sequence. I had thought pressurising the rail was part of the priming.

Longer story this was a snapped timing chain, engine stripped and head off, rebuilt and started with new injectors. Tried the injector code and learn, failed for unstable pressure.
tried pump learn, failed and threw up a P2635 fuel flow regulating electrovalve. changed the regulator, pressure valve and sensor, didnt help.
diagbox shows no pressure till engine starts cranking and jumps around from 190 bar to 450 bar while running.
so thinking about next steps, but the zero pressure at prime is throwing me a bit.

[knobby1]

Does the Relay have an "in-tank" pump..?? The Euro-5 Transits do. However, since the main pump isn't turning when just the ignition is on, I suspect you'll see little to no FRP.

Lord Knobrot

[tryagain12]

Thanks for the replay.
Yes in tank pump, so diesel up to the HP pump. Didnt look at it yesterday, but half ready to drop all the original parts back in, injectors, regulator, pressure valve and start again from there. Reading through other posts, drawing in air seems a possible cause, so will pull the filter housing out again, open n seal again and have a good look around the pipes.
But at least I know the no pressure till cranking is OK

[andz327]

What year is the van

Sent from my SM-G975F using Tapatalk

[tryagain12]

It's 2011.

[tryagain12]

still trying to work through this, but coming up with more questions than answers at the moment.

Haven't dropped all the original parts back in, that will be the weekend if i do it, but leaning towards the HP pump as cause So pulled it off again tonight and this is another question ive got before i splash wedge with a new or recon pump.
Just turning the pump keyway by hand it doesn't feel very smooth, and i can only turn it 270 degrees back and forth, no fully round. This is where my knowledge of how these things work let me down, I dont know if that is normal or not ? The rough feeling when turning is enough for me change it out, if it wasn't such a big chunk of money. 300 or more is a lot just to see if its that.

So new fuel filter
recon injectors
new regulator
new pressure valve
new sensor
lifted out the fuel filter housing, cracked open, cleaned seal, refitted, checked pipes, nothing obviously wrong.
If not the pump, only leaves injectors, but then they would need to be worse than the originals. Reaching the end of my diagnostic skills (if any) any thoughts ?? 120k on the van, whats a pump expected to last ?

[karl]

very uncommon for the pumps to go

ive striped them down and never seen a problem in them

what codes do you have from diagbox

diagbox is very good if you know how to use it

also why you doing a pump just reset the counter as if you put a new pump on ?

[tryagain12]

P1304 programming of injectors
P1306 high pressure pump programming
P2635 fuel flow regulating electrovalve

The P2635 comes up after the pump learning fails, and the reason given for the injector learning fail is unstable fuel pressure.
I drove it for a couple of miles to see if anything else came up but that's all that shows.

[tryagain12]

Just to shut this thread down, got a new HP pump delivered and fitted it after work. Fuel pressure much more stable, but still well above target. Got the pump learn complete, then the injector learn. Faults cleared and EML off, and the measured pressure now following target, and all sounding much better.
So looks like pump was fecked, god knows how long it's been like that. Hope that's me for a bit before the next wave of misery hits.