Hi everyone, first time caller, long time listener.
My car:
2007 Mini Cooper S hardtop, R56 (N14) 110,000 miles
Symptoms:
1. Crank, NO START
2. Fuel pump does NOT prime when ignition is turned on
3. Fuel pump does NOT run when cranking engine.
4. Fuel pump DOES work when 12V is applied directly to pump
5. Wire connector at fuel pump shows good ground (brown wire) but no power (blue/white wire) when key is in the ON position
6. Tested continuity of blue/white power wire from panel to pump- it's a good wire
7. Fuel pump runs when 12V applied directly to blue/white wire at JBE
8. Tested K96 relay- all good
9. Tested all fuses- all good
10. Tested for power & ground at K96 socket at JBE, all good
11. Tested main DME relay (K6300) - all good
12. Tested for power & ground at DME relay (K6300) socket at JBE, all good
13. Replaced JBE with used JBE bought off Ebay (seller said it was good working JBE). My JBE had water damage.
14. New JBE seems to work (everything in the car powers up like it should except fuel pump)
15. Replaced camshaft sensor & crankshaft sensor
16. Replaced plugs & coils, changed oil & filter, new valve cover gasket
17. Opened up valve cover- no obvious timing chain issues
18. Sprayed starter fluid into air intake to force car to start but still won't start. Cranks but no start.

The fuel pump NEVER primes when the key is on and I don't get any voltage on the blue/white power wire at the fuel pump connector. But, I know the wire works, I know the fuel pump works, I know the relay works, and I can send power to the pump from the wire at the JBE and it works. I even tried starting the car while manually running the fuel pump, but still no go.

Here's the weird part. AFTER I try to start the car and nothing happens, I stop cranking the engine, then whadya' know, THEN the fuel pump decides to come on!! This is about 5-7 seconds after I stop trying to start the car. The pump runs for about a full second and then stops. It's the craziest thing! I have repeated this over a dozen times. I put the multimeter on the connector and sure enough, it shows 12volts for about 1 full second each time. It's almost as if it's getting its signals reversed!! It doesn't come on when it's supposed to, it comes on afterward, when I don't need it!!

This leads me to believe I've got a faulty ECU sending mixed signals to the relay. Could it be anything else? What do you guys think-have you seen this before? You guys are the experts so I thought I'd ask you. I will say that the car had been sitting outside for a good 2 years in wet conditions and water leaked into the car. I bought it from the owners who gave up trying to fix it.

Thanks for your help!!

 

There are two fuel pumps. You have the low pressure pump in the tank along with the high pressure pump that is attached to the intake camshaft. The low pressure pump only supplies priming pressure to the HPFP and only does so when it is needed (i.e. the pressure to the HPFP is not up to requirement). It sounds like your HPFP may have failed so it is not supplying fuel to the injectors. These are notorious in the N14 for failing so it would not be surprising either.

 

Thanks for the reply jwzimm. I understand about the HPFP, but doesn't the low pressure pump at least PRIME when the key is on? Mine doesn't even prime. In other words, whether the HPFP is faulty or not, the low pressure pump in the tank should always prime no matter what, right? Are you saying that the low pressure pump doesn't necessarily prime each time the key is on? I was under the understanding that the low pressure pump always primed when key is turned on. Thanks any other hints would be appreciated.

 

I am not super familiar with the system so I am operating more on general experience here.

My thought is that the LPFP would only run when the DME senses that the low pressure side of the fuel system has fallen below the requirement. If the HPFP is completely TU it wouldn'y pull any fuel from the low pressure side. Since the fuel system is not a "return" style system that would bleed off the fuel pressure once the pump shuts off, I would not expect the pump to necessarily prime every time you turn the car on.

I would also expect to see some fault codes show up if there is indeed an issue in the low pressure fuel side as the DME would not be happy with what it is seeing. Do you have a BMW/Mini specific diagnostic reader that you can use to scan the DME for any fault codes?

 

got it. That makes sense. I don’t have a BMW/Mini specific OBD reader, just a generic one that pulled about 40 codes. Got any suggestions?

 

I use the Carly App on my iPhone. You can buy the app and then get the dongle off Amazon. It can read BMW/Mini codes as well as perform coding changes (options).

 

you solved the problem ??

 

did you find a solution to this problem? I'm having the same problem

 

And I am having the same problem.

I have come to the belief that all the posters about similar problems either gave up and sent the car to the junkyard for scrap, or fixed it, and are clueless about posting the resolution so as to help others. Numerous threads posted for help, and suggestions are given, but the OP never closes the loop on the problem!!!

 

2010 MCS My cure was replace JBE fuse box, hard wired lpfp relay failed.

 

i would agree 100%

 

every winter when i store mine, it does the same thing. i replaced my box 2 years ago, and this winter back to square one. cranks no start. some days the fuel pump comes on, today it won't