I'll apologise in advance for the long post...but really hoping someone can shed some light or make some suggestions here...it's driving me insane
I've been having an issue lately with delayed/hesitant power delivery. I was going to post about it but then I had a fuel leak on my high pressure fuel pipe (pump to rail), which is now sorted.
I'm not sure if the two are linked, and was wondering if anyone has experienced any similar symptoms.
Sequence of events:
- Started developing a noticeable delay in power delivery when flooring accelerator; previously pick up was nice and responsive, even below turbo rev range, then when turbo kicked in it was like a rocket
- Also a bit hesitant when accelerating moderately through the revs; noticed between 2,000 and 3,000 I'd say
- Before I could get across to see the Autolusso lads I broke down with the high pressure fuel pipe leak (http://www.alfaowner.com/Forum/alfa-...esel-pipe.html (Leaking High Pressure Diesel Pipe)
) this turned out to be exactly as R.T. suggested, and was a cracked pipe at the very end of the pipe (fuel pump end)
- Replaced the pipe, changed the fuel filter, and flushed out the rail and injector pipes with diesel to get any crap out the system; there were some little particles, hard to say what it was; I didn't fancy removing the fuel pump and checking it/flushing it out, beyond my capabilities; R.T. did suggest it could be due to the fuel pump valve being clogged up and not operating correctly (I still don't know if this is the case or not) sounds plausible
So that's where I am at the moment, and I'm still having exactly the same symptoms of delayed acceleration. So for the time being I'm pretty reluctant to accelerate beyond 2,000rpm as I'm concerned I might cause another high pressure spike and burst another high pressure fuel pipe, so driving ridiculously cautiously
I spoke to Dan at Autolusso (I'm going to see him on Saturday...if I make it over there!) and he was saying that there was someone had recently went through 3 or 4 of the high pressure fuel pipes that had failed on mine, but I'm not sure what the cause of that has been. Maybe it was someone off the forum? Pipe up if it was you (excuse the pun)
So two issues, but maybe linked?
I don't know how the high pressure fuel pump works. I understand there's a valve to regulate the pressure which I guess is based on the pressure measured in the common rail as that's where the pressure sensor is? If anyone can go into detail that would be great.
Could my symptoms be due to a dodgy high pressure fuel pump? Floor it, sticky valve, not enough pressure in the rail so poor injection, poor acceleration, valve starts to operate, pressure builds, good injection, acceleration picks up and gets going. But now and again the ECU overcompensates for the low pressure, then BANG massive spike of high pressure, high pressure fuel pipe cracks and leaks...OR, is that not possible?
If anyone has any thoughts or any experience of the same problems, any help would be much appreciated