Crank No start GTI

[Ex2B8]

Hello everyone,

I have been through a long ordeal with my 2007 gti with the FSI motor and I am hoping maybe someone could help me here. So I was driving the vehicle when I started getting what felt like fuel cuts and the car went into a limp mode. When I got the car home it had no check engine light on but gave a code for low fuel pressure. I cleared the code, but came right back after a short and easy drive. I went ahead and replaced the high pressure fuel sensor on the rail and it ran fine while on a test drive until I went full throttle and got a fuel cut and the car went back into limp mode and shortly after, the car died and would not start. I let the car sit for about ten minutes, then the car started and I babied it home. I ordered another high pressure fuel sensor and a low pressure sensor (the one on the side of the hpfp). The car sat for a week until the parts arrived and before replacing them I attempted to move the car but it would barely run and die almost immediately. I replaced both sensors which didn't fix the issue. I then replaced the hpfp (cam follower and cam lobes were fine) and lpfp, along with the fuel filter. The car still will not start, it cranks and occasionally fires but never seems to catch.

I checked and the timing belt is not broken, every cylinder is getting spark, I did a compression test which was a little concerning: (150,150,120,119). I ended up getting a VCDS cable which has shown that fuel pressure is within the expected range and the injectors seem to be firing (Injection timing displays as 3.57 while cranking), interestingly there are no active codes but I did find that the ignition timing BTDC is at 9.8 while cranking (I am unsure if this is within normal range). My thinking is that the timing belt skipped a tooth or maybe the cam chain broke/stretched? Possibly the engine had a fuel delivery issue and I forked it while driving it? I am not really sure what to check from here or if there is something I can check with VCDS to verify a timing issue when the engine will not start.

Thanks for any advice!

 

[ROH ECHT]

When you replaced the LPFP...what did the control module look like on top of the LPFP?
Did it have any signs of melting?
Also...what was the code, it did store, that you saw?

Compression difference limit is 3 bar/43 psi. You may want to try a leak-down test.
To see if it reveals where it loses the air to point you toward any internal damage.

 

[Ex2B8]

When you replaced the LPFP...what did the control module look like on top of the LPFP?
Did it have any signs of melting?
Also...what was the code, it did store, that you saw?

Compression difference limit is 3 bar/43 psi. You may want to try a leak-down test.
To see if it reveals where it loses the air to point you toward any internal damage.

I don't remember the code specifically, and the control module looked fine and pump is turning on. I will try a leak down test.
Thanks!

 

[Ex2B8]

When you replaced the LPFP...what did the control module look like on top of the LPFP?
Did it have any signs of melting?
Also...what was the code, it did store, that you saw?

Compression difference limit is 3 bar/43 psi. You may want to try a leak-down test.
To see if it reveals where it loses the air to point you toward any internal damage.

Leak down test seemed fine, only about 1 psi loss in each cylinder. I believe the code was specifically for low rail fuel pressure.

 

[ROH ECHT]

But where is air leaking? If you do another LD Test; If rapid leaking is detected; through the rings...you can detect (hear/feel) air with the dipstick removed. If leaking from the intake valves...disconnect the manifold-to-pcv tube and listen/feel the opening in the intake manifold. If leaking from the exhaust valves...hear/feel at the exhaust tips. But if it only leaked one psi while doing a LD test...then not likely going to hear constant air coming through any of those openings.

If the code was for a mechanical failure to provide too little fuel, as reported by the G410(which is new, correct?), then all it can be is; a tired LPFP__failing control module__Fuel filter failure (be sure it was a 6.6 bar regulated filter and a 4 bar wasn't installed)__clogged delivery lines__plugged low pressure fitting on the HPFP (if it is the bamboo fitting)__internally clogged HPFP.

Were the two sensors genuine OE or what? You may need to have the fuel pressure checked within the lines using a gauge. I would try a full scan again with your vcds. List any 'Pxxxx' codes you see stored. Also...look at its Readiness Status. Are you yet familiar with running data logs with vcds? This would be a data log done throughout a full rev pull in one gear at full throttle while driving. It would be helpful to see what the fuel pressures are for both high and low sides. These would be vcds Groups 230 and 231 to show both its specified and actual from about 2k rpm to redline. Include another, such as Group 003 so we can see throttle drive angle is indeed open. And select the 'turbo' button before beginning the logging.