To all E36 Masters, for the past 3 months, I have experienced the same problem after refueling. Every time after refueling, right at the fuel pump, the engine won't ignite at the first turn of key. I have to start the engine twice. If I tried it hard at the first turn of key, it needs probably 5 more seconds to get the engine ignited. What is possibly happen? Plugs, fuel pump, AFM or something else? Please enlighten me. Thanks a lot.
Difficulty after refueling
- Thread starter baoguan
- Start date
-
Click here to become an Official Member of BMW Club Malaysia Download Form
I am only guessing based on your description.
When you want to refill, you open the fuel cap. Tank de-pressurised. Petrol return back to tank
from the fuel line. Normally, this is prevented from happening by the check valve at the outlet
of the fuel pump.
To confirm it is the check valve problem, after filling petrol, turn on the ignition.
Do not immediately crank the engine. wait for about 10 to 15 seconds.
Crank the engine after 15 seconds. If it start without any problem, then it is your check
valve.
Note: the 15 seconds wait is to let the fuel pump to run and pressurise the fuel line to
the fuel in the engine compartment.
Another way to check is to connect a pressure gauge at the fuel rail and check the fuel pressure.
When you want to refill, you open the fuel cap. Tank de-pressurised. Petrol return back to tank
from the fuel line. Normally, this is prevented from happening by the check valve at the outlet
of the fuel pump.
To confirm it is the check valve problem, after filling petrol, turn on the ignition.
Do not immediately crank the engine. wait for about 10 to 15 seconds.
Crank the engine after 15 seconds. If it start without any problem, then it is your check
valve.
Note: the 15 seconds wait is to let the fuel pump to run and pressurise the fuel line to
the fuel in the engine compartment.
Another way to check is to connect a pressure gauge at the fuel rail and check the fuel pressure.
baoguan;644019 said:
The check valve is a integral part of the pump located at the outlet of the pump.
AFAIK, it is not serviceable. You have to change the pump even if only the check valve is faulty.
The sad new is that you cannot buy the pump alone. It comes as a set with the fuel level sensor.
Fuel pump and fuel level sensor - BMW parts catalog
turbology;644480 said:
Fuel pump will turn on when Igniton key is turn ON. This will allow the pump to pressurize the fuel line and the fuel rail.
However, the fuel will be cut-out by the DME when it detect a crankshaft sensor failure or crash condition from the General Module.
EL118;644503 said:
Can you describe the sound from the pump?
A proper way to check the condition of the fuel pump is to check the pressure at the fuel rail.
The mechanic will connect a pressure gauge at fuel rail. Pressure should be constant cos excess fuel
is return via the pressure regulator located at the end of the fuel rail.
If the pressure is not up to expected value of 3 to 3.5 bar, then the pump may need to be changed.
However, sometime, the problem could be due to a chocked or dirty fuel filter.
Master Jarance,
I think the problem is with the check valve. I followed your instruction, to turn on the ignition and waited for about 10 seconds. After that, the engine cranked and ignited without hesitation! So shall I fix the check valve or just wait for 10 seconds everytime upon refueling?
I think the problem is with the check valve. I followed your instruction, to turn on the ignition and waited for about 10 seconds. After that, the engine cranked and ignited without hesitation! So shall I fix the check valve or just wait for 10 seconds everytime upon refueling?
baoguan;645179 said:
I doubt that you can fixed just the check valve only. Looking at the picture of the fuel pump, it look like every thing
is completely sealed.
My recommendation is to replace the fuel pump. I dont advise you to service the pump cos
you might damaged the seal and allow petrol to get inside the motor of the pump.
btw, there are people who retrofit other manufacturer pump for bmw.
hint: perdana or waja also use bosch pump.
