Bad fuel pump or fuel regulator - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Brian Minson · 02-15-2020, 01:28 PM

Hey guys, my 2001 986S has been having trouble starting, once started it doesn't like to move when you give it some gas. I changed out the MAF, testing for an intake leak and still no change. Today I hooked up a fuel pressure regulator to my system and looks like about 25 psi or 1.7 bar is what the engine has. I pulled the vacuum line to the air regulator and it didn't change the pressure at all.

I haven't pulled the fuel pump relay to test it yet, but would you agree with me this is a fuel pump on its way out?

Here is a video of whats going on.

https://youtu.be/hddx5Ux1v4Y

Brian Minson · 02-22-2020, 08:07 AM

UPDATE: I pulled the fuel pump relay and jumped it running the pump for 30 seconds, grabbing fuel at the inlet before the fuel filter. 850 cc damn near on the mark!!! I went ahead and replaced the fuel pump relay just for good measure.

I then pulled the fuel return line and did the same test... almost BONE DRY!!! I guess I am going to get another fuel filter, as this all kinda started after I replaced the fuel filter a few weeks back.

Any suggestions?

Brian

Zzorro · 02-22-2020, 11:29 AM

Had intermittent issues with loss of power while driving. Never had issues starting it, would idle fine and "cruise" fine. But sometimes when I wanted to punch it it would bog down terribly but never stalled out. And the bogging would only happen intermittently, Maybe 30% of the time. Strange symptoms.

My 98 Boxster had ~170k km (~110k miles). I had already swapped out the MAF earlier after my durametric was showing some emissions system related codes.

Purchased a VDO unit on Rock Auto. There are way cheaper ones out there though. I didn't bother replacing the sending unit.

It seems to have corrected the issue. I will see how that works this summer.

On your video, sounds to me you have a pretty high pitched whine at idea compared to mine. Maybe that's your fuel pump begging for mercy? I had some noise that went away after my pump was swapped out. Confirming further that my pump needed to be changed.

Hope that helps out.