Hi,

TL;DR

Would I expect a full 5.00 MPa of fuel pressure from the HPFP during the starter motor cranking it but the engine not starting up?


Longer story:

I bought a broken 2007 R56 Cooper S N14 engine (with JCW kit) UK model, 130k miles. It wasn't making boost with an incoherent boost error and it had a super knock error (and a couple of knock sensor errors). It was idling (not perfect idle, but kept going) and would drive, slowly.



Anyway, the boost controller wasn't holding vacuum, so I've changed that (I'm pretty familiar with BMW turbos). While I was there I walnut blasted the dirty intake valves and swapped over the knock sensor, buttoned it up and now it barely idles, it if starts at all.



I then changed the plugs - the old ones were apparently only 15k miles old, but bits of insulation cracked off. That didn't help. The unbranded coils are also only 15k miles old - I've not changed those.

I visibly checked the Vanos filter and it was a bit dirty, but not bad.



I've checked the low pressure fuel pump and it doesn't seem to alway prime, but then sometimes it does. It does always get 12v while cranking. I tested it with a pressure gauge plugged in near the HPFP and it gave 5bar either jumped with 12v or plugged in and ignition on.



However, with everything plugged in as it should be and looking on ISTA it was only getting to 1.82 MPa while cranking rather than its set point of 5.00 MPa. I'm suspicious about the high pressure fuel pump...

Would I expect a full 5.00 MPa of fuel pressure from the HPFP during the starter motor cranking it but the engine not starting up?



I did a compression test today with the low pressure pump unplugged and got decent 160psi compression on 3 cylinders and 110psi on Cylinder 3 that had ingested some walnut shells - I'm hoping these just need to be burnt off once it is running! Some oil down the plug hole improved this to 150psi, so I don't think this is the problem.



However, once I put the plugs back in and plugged in the fuel pump it ran for 30 seconds then died, and then wouldn't start.

Could the HPFP built up enough pressure in the cranking for the compression test to keep it going for a while, or is this just a red herring?



I think the HPFP is faulty - what do you think?

 

Bro, please tell me u found out what the issue Was?

Having the same issue here as well.... changed plugs, changes turbo as it was burning oil, changed the hpfp with a secondhand one, car now wont even start and idle....

 

If you look, I had a similar issue not too long ago, it was the HPFP. I changed it out with 2 different ebay HPFP's and nothing changed, it wasnt until I got one from FCPEuro that it was fixed.

 

Yes, i would not run the ebay ones and go with the Genuine PSA one we carry or another OEM we carry.

Ebay HPFPs review: https://www.northamericanmotoring.co...ebay-hpfp.html