Fuel pressure dropping

[BRiley]

All:

I had a crazy fuel delivery issue the other day and it left me stranded after sputtering to a stop. No crank. I got a EKP relay ground fault. Replaced the relay with a new one. Still same no start condition. Eventually it will crank if I start it hard enough.

Measured the pressure at the regulator, and it was zero. Activated pump with INPA and it goes to 70. Then it drops to zero pretty quickly after I stop that job. Get in to crank. Car is turning over the first time, and the pressure goes to maybe 30. Crank again, I get to 50. If I catch the third crank before pressure drops too much, I get all the way up to 60-70 and the car cranks.

I replaced the pump and filter about 8-9 months ago because the car kept turning off. Seemed to do the trick. No more shutdowns when driving slowly. I used a Hella pump from Bimmerworld. Could the check valve go bad that quickly? I’ve only put a couple thousand miles on the car since I replaced it. What should I do next?

Thanks!!

[digger]

Seems like FPR issue

[crispychicken49]

Hey I just updated a similar thread I started this morning! After some reading on the Hella pump I pulled mine and found the check valve failed, likely what yours is too. I even had an EKP relay fault as well which logically didn't make sense.

Replacing the pump unit is what fixed it for me. Some options for you:

Radium sells a FP adapter kit and walbro GS pump that works. Adapting the adapter kit to the Hella unit requires some modification of the Hella fuel pump adapter. Unfortunately the suction tube Radium supplied did not work with the Radium supplied Walbro pump, the tube was loose over the output nipple on the pump. The Hella unit terminal plugs do not work with the adapter kit either, I recommend directly crimping the Walbro harness (sold separately not on Radium's site) to the Hella unit if you go this route. You will also likely have to figure out the suction hose as well. This may be a better option if you still have your OEM fuel pump assembly lying around. ~$200 all in.

Otherwise you can chance it on a used unit on eBay if you want to save some money. Otherwise an OE unit (Delphi) from whichever vendor is cheapest will be your next best option. ~$650. This was the one I went with since I'm tired of towing my cars home! I recommend also getting a new OEM Blue gasket if you didn't get one on the last go around. I had a consistent fuel smell in the car a full tank that disappeared when I replaced the gasket.

[sapote]

All:

I had a crazy fuel delivery issue the other day and it left me stranded after sputtering to a stop. No crank. I got a EKP relay ground fault. Replaced the relay with a new one. Still same no start condition. Eventually it will crank if I start it hard enough.

Fuel pump issue should not cause no crank issue, as I don't see how the DME knows the pump status. Do you have stock EWS or it's been bypassed?

[sapote]

Hey I just updated a similar thread I started this morning! After some reading on the Hella pump I pulled mine and found the check valve failed, likely what yours is too. I even had an EKP relay fault as well which logically didn't make sense.

Replacing the pump unit is what fixed it for me. Some options for you:

Radium sells a FP adapter kit and walbro GS pump that works. Adapting the adapter kit to the Hella unit requires some modification of the Hella fuel pump adapter. Unfortunately the suction tube Radium supplied did not work with the Radium supplied Walbro pump, the tube was loose over the output nipple on the pump. The Hella unit terminal plugs do not work with the adapter kit either, I recommend directly crimping the Walbro harness (sold separately not on Radium's site) to the Hella unit if you go this route. You will also likely have to figure out the suction hose as well. This may be a better option if you still have your OEM fuel pump assembly lying around. ~$200 all in.

Otherwise you can chance it on a used unit on eBay if you want to save some money. Otherwise an OE unit (Delphi) from whichever vendor is cheapest will be your next best option. ~$650. This was the one I went with since I'm tired of towing my cars home! I recommend also getting a new OEM Blue gasket if you didn't get one on the last go around. I had a consistent fuel smell in the car a full tank that disappeared when I replaced the gasket.

A good FP with a bad check valve should not cause a stalled engine or not running engine.

[sapote]

I had a crazy fuel delivery issue the other day and it left me stranded after sputtering to a stop. No crank. I got a EKP relay ground fault.

As it had been discussed before about the relay ground fault code, I don't see a way for the DME to know about the relay status. So this error code only happened when your engine was stalling or not running? What is the error code and read by what tool?

[BRiley]

Fuel pump issue should not cause no crank issue, as I don't see how the DME knows the pump status. Do you have stock EWS or it's been bypassed?

I have stock EWS. I read the code with my Foxwell. Then INPA and Tool32. The code would come on during the crank. I am gonna go test to rule out the FPR. Thanks for the advice.

[sapote]

I have stock EWS. I read the code with my Foxwell. Then INPA and Tool32. The code would come on during the crank. I am gonna go test to rule out the FPR. Thanks for the advice.

can you confirm you have no problem of cranking? IOW, it cranked but not fire up.

[sapote]

I have stock EWS. I read the code with my Foxwell. Then INPA and Tool32. The code would come on during the crank. I am gonna go test to rule out the FPR. Thanks for the advice.

What is the code number?

[BRiley]

What is the code number?

Crank is fine. I even get RPM while cranking. Here's the code:

[sapote]

Error code = 1.
The description says nothing about Ground Fault, just fuel pump relay (and I wonder why TIS wiring diagram shows no feedback wires from relay to DME).
I would bypass the relay with a simple toggle switch to apply 12v directly to the pump and see if this fixes the problem.


From this https://bmwfault.codes/Lookup:

[BRiley]

Interestingly I have bypassed the relay. It doesn’t solve the no crank. It’s either the check valve or FPR. Still need to test that but I have to grab some pliers to pinch it

[sapote]

Interestingly I have bypassed the relay. It doesn’t solve the no crank. It’s either the check valve or FPR. Still need to test that but I have to grab some pliers to pinch it

Do you really mean no crank, again?
As I pointed out before, a bad check valve is not the cause of the low pressure problem. With 12v applied to pump, then the issue is either the pump is weak, or the pressure regulator is bad.

[BRiley]

Ohh. Gotcha. That makes sense. I am gonna try and test the FPR today just to make sure before I install a new pump (again). Thank you for your help!

[BRiley]

Alright. I was able to rule out the FPR. New pump installed, and things are back to 100%. DO NOT BUY that Hella fuel pump made in China. /sigh