New member fuel starting issues

A

agrimes89

Member
Hi there , owned my e85 z4 3.0 for 8 months or so now . The last few starts i have felt something didn't feel quite right with the way it sounded when i started it up. Drove down to the gym the other day and when i came out the car would not start . It briefly fired up im guessing with the fuel that it had in the system then died almost instantly . Just cranks over now , not even trying to fire. Tried to swap about all the fuses i can find relating to the fuel pump.

I have read the codes and have 1 for fuel pump relay. Now i cannot locate this relay. Only information i could find on it was e46 related . Pulled out the glove box and fuse box as it shows to do .

In an e46 there is green relays behind there of which 1 is fuel pump relay and another is the horn relay. Apparently you can swap these to test it. In my car there is only 2 purple relays and a salmon pink 1 of which swapping around hasn't changed anything.

Further research online is suggesting these cars dont have a relay for the fuel pump, which i find strange due the pretty much being the same as a e46 in all but body. Also having a code appear for the relay makes me think there is .

I am struggling to find much information about relays in general on our cars. There is another box under the bonnet in which there are more relays ( green and a blue ) . I swapped the green with another from my friends 330ci but it made no difference.

Im dreading finding out its the actual pump as that will be a nightmare to change.

Sorry for the long essay for a first post . Hopefully someone can help. Will need to have the car recovered home if it isn't something simple .

Cheers , Andy
 
The fuel pump on E85 models is controlled by the EKP module. This is located in the boot near the battery.
They have been known to suffer from a bad earth connection, it's near to the unit.

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The fuel pump speed is varied under control of the EKP, it runs the pump at full speed for starting, and then modulates it to control fuel rail pressure as detected by the DME.

If you suspect no fuel pressure and want to manually activate the pump, connect fused jumper wires (yellow arrow) from battery across the fuel pump connector (red arrow) terminals. Red with white is battery volts. Brown is ground. Try this and see if it starts!

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Connect DVM across fuel pump terminals while backprobing (yellow arrows) then plug the connector (purple arrow) back in. These are the two terminals on my car. You will be testing voltage across the large wires at the connector. Red with white is battery volts. Brown is ground. Turn key ON, DVM should read battery volts (around 11-12 volts). If no voltage is found, check relay and fuel pump fuse. With key ON, fuel pump will receive voltage for a 3-5 seconds to prime system, (if engine doesn't start). I suggest load testing using a test light and a DVM. Connect DVM across fuel pump electrical connector terminals and take a reading, it should read battery volts when key is turned ON. Then connect an incandescent bulb style test light to battery ground and touch the test light probe tip the positive wire you are back probing with DVM. Your reading should hold steady, a maximum drop in voltage of 0.5 volts is OK. Anything more is a problem. In this photo, voltage held steady. If you have no voltage the DME may not be activating the module or the module is faulty. You can also test voltage to the module. The blue and yellow wires on the left side of the connector are the CAN BUS communication lines. K-BUS is the white with red and yellow. The black with green (blue arrow) is ignition voltage to module (battery volts with key ON) from fuse 44 (5 amp fuse). Brown (green arrow) is the ground and white arrow is battery volts all the time from fuse 4 (20 amp fuse).

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HTH

Mike
 
Thanks for all that information . That will be very helpful if i can find that part... The black and beige panel is down beside my battery which is where the spare wheel would be in another car . That plugged module is nowhere i can see?

Il attach pictures of my boot. Excuse the mess and bits of wood. Was mocking up a build for my air suspension.

Not the clearest of pictures as it was dark but as you should be able to see , i do have that beige and black box but its down by my battery and i couldnt see anything else down there with it except the battery and iv pulled all the carpets out round about the boot area...


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Not that i seen. I will go have another look after work and properly strip the boot out. It must be there somewhere unless that is a z4m only part? Thats the z4m boot i believe shown above with the battery box up out of the way for the quad exhausts.
 
Surely it's that black and beige box next to your battery? I guess it must be a yellow connector on non-M's.
 
Can not find any sort of module in the boot . Have tried all sorts of fuses and relays and can not find the relay that I have the code for . Next stage I suppose is checking the actual pump with a multimeter but I can’t do that till i get it home . Typical no tow hook with the car :x I am inclined to still think it’s this relay or wiring somewhere that’s the problem but I’m struggling so far .




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"mocking up suspension" when I first saw it, I thought why is he building a stud wall in his boot :D
 
Looks like tis and real oem are wrong. This is the relay that controls the fuel pump with my finger on it, on the back of internal fuse box.

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Mike
 
Some good detective work there . I’ve searched and researched for days . Whipped out now , new one ordered and hopefully we have solved the problem .
 
agrimes1989 said:
Some good detective work there . I’ve searched and researched for days . Whipped out now , new one ordered and hopefully we have solved the problem .
Click to expand...

Pull the relay out and pop the plastic top off, stick it back in and using your fingers, close the relay manually with the ignition on and you should hear the pump running. If so, I'd pop an elastic band on to hold it closed and then try starting the car.

Mike
 
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