2011 x3 i35 90psi after replacing HPFP (SOLVED)!

Hatethiscar · 09-14-2023, 05:44 PM

Just purchased this 2011 x3 i35 130,000miles.
car is in limp mode, codes for low fuel pressure at start up and map sensor. Rail pressure is 93 psi. Pulled hpfp and the cog that engages the shaft that turns it was broken off. Bought new pump, installed and still same fuel pressure. Verified 12v to the hpfp solenoid. Changed rail sensor. Can’t figure why it seems that the dme isn’t commanding the hpfp to make pressure. Been at this for three weeks now. Thanks!

Hatethiscar · 09-16-2023, 04:33 AM

Ok, after ripping my hair out for three weeks, pulling codes and chasing dead ends trying to figure out why two high pressure fuel pumps were inoperable ( one installed by previous owner and one by me) I have solved it.
These were both ebay aftermarket pumps. Neither would make pressure. The first one sheared the cog that engages the vacuum pump! NEITHER ONE HAD ANY OIL IN THE OIL SIDE OF THE PUMP! They came that way! For those that don’t know(I didn’t until I researched) these have an oil side and a fuel side separated by an oil seal. They use oil, not engine oil supplied by the car but oil that is sealed inside the pump. It uses this oil to creat hydraulic pressure to then transfer that pressure to a bellows sort of device that then builds fuel pressure. If the oil side has no oil in it from the factory as mine didn’t , it won’t work! No matter how much hair you pull or how many codes you pull!
So the moral of the story, if you buy an ebay pump and it doesn’t work right out of the box, remove the three t20 bolts and see if there’s any oil in it! If not, completely submerge it in 90w gear oil and reassemble WHILE submerged. Hope this helps someone!

09-14-2023, 05:44 PM	#1
Hatethiscar Registered 0 Rep 4 Posts Drives: 2011 x3 Join Date: Sep 2023 Location: Alaska iTrader: (0)	2011 x3 i35 90psi after replacing HPFP (SOLVED)! Just purchased this 2011 x3 i35 130,000miles. car is in limp mode, codes for low fuel pressure at start up and map sensor. Rail pressure is 93 psi. Pulled hpfp and the cog that engages the shaft that turns it was broken off. Bought new pump, installed and still same fuel pressure. Verified 12v to the hpfp solenoid. Changed rail sensor. Can’t figure why it seems that the dme isn’t commanding the hpfp to make pressure. Been at this for three weeks now. Thanks! Last edited by Hatethiscar; 09-16-2023 at 04:36 AM..
	Appreciate 0 Tweet Quote

09-16-2023, 04:33 AM	#2
Hatethiscar Registered 0 Rep 4 Posts Drives: 2011 x3 Join Date: Sep 2023 Location: Alaska iTrader: (0)	SOLVED!! Ok, after ripping my hair out for three weeks, pulling codes and chasing dead ends trying to figure out why two high pressure fuel pumps were inoperable ( one installed by previous owner and one by me) I have solved it. These were both ebay aftermarket pumps. Neither would make pressure. The first one sheared the cog that engages the vacuum pump! NEITHER ONE HAD ANY OIL IN THE OIL SIDE OF THE PUMP! They came that way! For those that don’t know(I didn’t until I researched) these have an oil side and a fuel side separated by an oil seal. They use oil, not engine oil supplied by the car but oil that is sealed inside the pump. It uses this oil to creat hydraulic pressure to then transfer that pressure to a bellows sort of device that then builds fuel pressure. If the oil side has no oil in it from the factory as mine didn’t , it won’t work! No matter how much hair you pull or how many codes you pull! So the moral of the story, if you buy an ebay pump and it doesn’t work right out of the box, remove the three t20 bolts and see if there’s any oil in it! If not, completely submerge it in 90w gear oil and reassemble WHILE submerged. Hope this helps someone!
	Appreciate 0 Quote