[nukezero]

Hello - need people's help or input.

Does anyone have datalog (datazap) showing what the LPFP fuel pressure is when the car is primed and prior to car starting?

My car is showing 2.655 PSI when the ECU has primed the fuel pump just prior to starting. I'm getting long cranks and i'm trying to isolate whether it is the HPFP or LPFP/regulator. What I'm seeing is that the LPFP takes about 1.6 seconds to reach 67 PSI followed by the HPFP starting to gain pressure.

When the car shuts down for just 30 seconds, is the LPFP fuel pressure supposed to remain pretty steady at > 50-60PSI ? Because I'm not seeing that. I'm seeing LPFP pressure fall straight off back to 2-3 PSI.

[titium]

hope this helps.

edit this app sucks!!

approx 80psi with engine rpm 0

[titium]

my rail pressure (hpfp) sits at 80 psi when i turn the car off never looked at lpfp.

Buraq asked peeps to post similar logs about a month or two ago. Search for that thread.

Also, long cranks are just one symptom. I would also assume that logging a third gear pull would be another dataset with which to pull some more meaningful information/symptoms from as well.

[nukezero]

Originally Posted by FCobra94

Buraq asked peeps to post similar logs about a month or two ago. Search for that thread.

Also, long cranks are just one symptom. I would also assume that logging a third gear pull would be another dataset with which to pull some more meaningful information/symptoms from as well.

Thanks guys - Found that thread. very very helpful. That shows me that the LPFP is long before at 80PSI before the HPFP starts cranking. In my case, my LPFP is sitting at 2PSI and cranks at the same time the engine is turning over.

Upon shutting down, the residual pressure according to bentley manual is not maintained and falls back from 76PSI back to 2PSI. This causes long cranks in both warm and cold start.