Few nights ago I had the car shut off while I was driving and after I pulled off, I could smell fuel around the engine bay but never tracked down the leak. When I got the car towed home I got to looking and still didn’t find any leak I pulled the manifold off so I could see if there was an injector leaking at the fuel rail but it looked good and no signs of a leak. When I put the car back together and hit the key it still just cranks with no fire and the fuel smell isn’t really there anymore but what I did notice is when I put the key in and the fuel pump primes it isn’t as quick as it was before and sounds dragged out and almost whining a little until it gets pressure built. Would that be something that sounds like the LPFP went out and is there any way to confirm that in VCDS before ordering a new one?
I did manage to find a very small slow leak coming down puddling right in the center front of the engine. I left the car keyed on for about 5 minutes hoping that the fuel pressure would stay and show the leak if there was one. I can’t backtrack the leak though, I would assume it’s trickling it’s way down from somewhere higher and further back somewhere.
There is a hole letting liquids to leak out of the V of the engine. Most likely you do have a leak under the manifold. It can be related to fuel lines, or fuel pressure sensor. HPFPs tend to leak internally into the engine, an external leak would be pretty obvious to spot.
The reason I’m getting so confused about it, is when I had the manifold off I reinstalled the fuel lines and keyed on the car to see if I could find anything and didn’t. And even now smelling around from the top side of the engine bay I can’t smell the fuel only when I’m physically under the car.
I guess my biggest question is, is there anything I could be testing to see if that in tank fuel pump is failing.
You can use a fuel pressure gauge, which you would need to plug anywhere before HPFPs. Fuel lines come into the engine bay through the right wheel well. You can check if fuel line isn’t damaged in that area, as that might give fuel odor in engine compartment area.
LPFP = MB 103-1
HPFP = MB 140-3
I did end up replacing the LPFP, noticable difference in the priming speed and also sound. This actually led to the small leak that I was getting to become more prominent and started dripping much quicker. The car wants to fire now but obviously is leaking enough fuel to keep it from starting. So now I need to track down this fuel leak. I’ll get the car up in the air with bumper off later this week but here is where I am finding fuel dripping from the front underside of the motor in front of the oil pan. There is also a “squeek” sort of noise after priming the fuel system coming from the back side of the intake that slowly goes away over about 60 seconds, assuming it’s just when there isn’t enough pressure to cause that noise anymore. Any help or advice would be appreciated. 