[coolchu001]

I bought a non-running 335d a few weeks ago.
Found that the issue was fuel delivery.

The low pressure pump, one underneath the rear passenger seat runs when directly wired to 12v. The connector going into the pump receives only 9-9.2v when unlocking the car/key in ignition. With this voltage, the pump doesn't seem to activate.

From what I found online, pumps in the 328/335i cars should be reading be around 10v.

Does anyone know what the normal voltage is at the low pressure pump plug/connector for the 335d?

The fuel pump controller/module appears to be the same for both i and d models so I'd assume the module may have gone bad...

However, even manually priming the low pressure pump with the battery for a few minutes, the car still failed to start.

[Yozh]

I can measure for you but not until the weekend. For some reason someone mentioned it's PWM.

[Hoooper]

Originally Posted by coolchu001

However, even manually priming the low pressure pump with the battery for a few minutes, the car still failed to start.

What does this mean? How did you prime the pump?

If you got the lift pump to run and it still didn't start, have you checked the rail pressure during cranking?

[coolchu001]

Originally Posted by Hoooper

What does this mean? How did you prime the pump?

If you got the lift pump to run and it still didn't start, have you checked the rail pressure during cranking?

The rail pressure is a problem as well. I know that needs to be addressed. But what I'm wondering is why the low pressure pump doesn't turn on when unlocking or with key in ignition. I just want to make sure it's the fuel pump controller/relay before swapping it out. I think 9V is too low and the problem lies with the controller...

[BB_cuda]

You better go read wrecker335d's thread. Something was up with the ECU not communicating with his pump controller module. He had changed both the lifting pump and controller and still no start.
http://www.e90post.com/forums/showth...1221553&page=2

see post #36. I'm not saying it is this for certain. I am saying wrecker spent lots of parts money and it ended up being this. I had thought I bricked my pump but thank goodness nope.

[Hoooper]

Originally Posted by coolchu001

The rail pressure is a problem as well. I know that needs to be addressed. But what I'm wondering is why the low pressure pump doesn't turn on when unlocking or with key in ignition. I just want to make sure it's the fuel pump controller/relay before swapping it out. I think 9V is too low and the problem lies with the controller...

Do you know for sure that its supposed to? Mine doesnt run when I unlock the car, or when I put the key in the ignition, or when I turn the ignition on without starting the car. When I do a fuel filter change I have the line disconnected when unlocking the car and turning the ignition on to connect software to run the pump, it has never run in that instance without commanding the pump to run via software.

[BB_cuda]

I didn't see voltage come out of pump module until I actually tried to crank. With ignition on only, no voltage at the pump pins. Yozh has a safer way to measure this as he can check without disconnecting the fuel pump. He installed blade terminals into the harness that connects to the pump's pins. I would minimize cranking with no fuel going to the HPFP.

Hooper commands his low press pump using bavtech cable. This is another safe way of checking pump without abusing the HPFP (if it isn't getting fuel). Good luck

[coolchu001]

Originally Posted by BB_cuda

I didn't see voltage come out of pump module until I actually tried to crank. With ignition on only, no voltage at the pump pins. Yozh has a safer way to measure this as he can check without disconnecting the fuel pump. He installed blade terminals into the harness that connects to the pump's pins. I would minimize cranking with no fuel going to the HPFP.

Hooper commands his low press pump using bavtech cable. This is another safe way of checking pump without abusing the HPFP (if it isn't getting fuel). Good luck

Thanks! I was able to activate the LP pump using the bavtech tool. Odd that the pump doesn't activate prior to starting/cranking the car. I would think it'll need to build up some pressure to assist the start. The pump does activate on ignition/crank.

Anyhow, there's barely any fuel coming out of the HPFP when cranked. Pressure seems to be good into HPFP. I have a re-manufactured HPFP on order (only $234!?).

[remlemasi]

Just wanted to say that threads like these with such helpful responses from expert members is a major reason why I plan to keep the D past CPO warranty, even in CA.

Here's to all who have given their time and knowledge with the expectation of nothing in return.

[Frediesel]

+1