check valve vs regulator

acarr6 · 11-12-2023, 04:42 PM

So, I’m chasing down a long crank cold start issue. I’ve replaced injectors, sending unit, plugs, fuel pressure sensor.

The only logical thing to replace would be the actual fuel pump itself which has the check valve in it.

However, I’m getting conflicting info. I know the regulator is in the fuel sending unit, which is what I initially replaced. The system is still bleeding pressure after everything I’ve replaced (at a fairly slow rate). Goes from full pressure to 0 over the course of about 1.5 days. Just want to confirm from the experts the actual fuel pump unit (not the sender unit side) has a check valve in it.

deansbimmer · 11-13-2023, 08:15 AM

Yes, the fuel pump (right well) has a check valve built into the motor. It's really the only component that goes bad in the pump assembly.

acarr6 · 11-13-2023, 08:38 AM

Quote:

Originally Posted by deansbimmer

Yes, the fuel pump (right well) has a check valve built into the motor. It's really the only component that goes bad in the pump assembly.

Good to know.. so in all likelihood after replacing every component, the last one is the culprit for my pressure loss lol

11-12-2023, 04:42 PM	#1
acarr6 Lieutenant 409 Rep 586 Posts Drives: E92 M3 DCT Join Date: Aug 2012 Location: GTA iTrader: (1)	check valve vs regulator So, I’m chasing down a long crank cold start issue. I’ve replaced injectors, sending unit, plugs, fuel pressure sensor. The only logical thing to replace would be the actual fuel pump itself which has the check valve in it. However, I’m getting conflicting info. I know the regulator is in the fuel sending unit, which is what I initially replaced. The system is still bleeding pressure after everything I’ve replaced (at a fairly slow rate). Goes from full pressure to 0 over the course of about 1.5 days. Just want to confirm from the experts the actual fuel pump unit (not the sender unit side) has a check valve in it. __________________ *** 2011 M3 DCT * Built 4.4L Stroker * Gintani supercharger * Brembo GT * BBS FI * OHLINS * Nardo Grey ***
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11-13-2023, 08:15 AM	#2
deansbimmer BimmerPost Supporting Vendor 3769 Rep 2,912 Posts Drives: 2011 E93 M3 Join Date: Nov 2014 Location: DFW, Texas iTrader: (17) Garage List 1988 BMW M3 [0.00] 2013 BMW M3 [0.00] 2011 X5M [0.00] 2011 BMW M3 [0.00]	Yes, the fuel pump (right well) has a check valve built into the motor. It's really the only component that goes bad in the pump assembly.
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