1999 E36 M3 Relay Location Confusion

[Ryan86]

Working on bringing a 1999 E36 back from the dead as a project car with my 14 year old daughter. The car has sat for 5 years, and was started every couple of months up until 6 months ago when it stopped firing up. Checked and no fuel pressure at the rail.

Yesterday, we drained 6 gallons of 5 year old fuel from the car, replaced the fuel pump, fuel level sending unit, fuel filter and installed new plugs/coils.

We put in 2 gallons of fresh 93 octane, I can now hear the pump and we've got strong pressure at the rail, but it still cranks with no starting.

I squirted a little starting fluid in the intake, and it stumbled like it was going to start, so I'm thinking the injectors are shot.

I'd like to check the DME relay, but I've got conflicting information about where it is. There's no white relay in the housing, and I'm getting conflicting info between the Bentley printed manual and a couple of places online.

Does anyone have a 1999 M3 that they can take a pic of the relay so I know where it should go? I suspect the PO might have just thrown a generic relay in for the DME.

Thanks,

Ryan

IMG_0456.jpg

[jhott66]

Position 1 is the fuel pump relay. Position 2 is the system relay. These are in the main fuse/relay box under hood on driver's side.
I'm not sure you can identify a relay based on it's color. I would confirm the correct part number is installed in the correct position.

[Ryan86]

Thanks for the reply. That's what it's supposed to be, as per the Bentley manual. However, this BMW NA electrical manual for the 1999 M3 shows the positions are reversed:

http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf

Just want to make sure I'm putting the correct part in the correct location.

Ryan

[jhott66]

Thanks for the reply. That's what it's supposed to be, as per the Bentley manual. However, this BMW NA electrical manual for the 1999 M3 shows the positions are reversed:

http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf

Just want to make sure I'm putting the correct part in the correct location.

Ryan

Ah, yes, I see what you are getting at. I just looked at the 1998 electric system schematic and it too has the fuel pump in position 2 and the main system relay in position 1. Reverse of the Bentley. I will go and look at my car and try to match part numbers on the relay with the diagram. Do you have the fuse/relay location chart included in the fuse box? That may be your best source of accurate information.

[jhott66]

Just looked at my car. relay position 1 is a BMW part 12631742690 "Salmon Red Multi-Purpose Relay".
relay position 2 is a light green relay with part number 61368373700. This appears to be the fuel pump relay? Next step would be to jump the power terminals in the #2 relay "block" and see if the fuel pump turns on. If yes, then you know position 2 is fuel pump. Then make sure you have the correct part number relays in position 1 and 2.

- - - Updated - - -

On the "no start" issue, not to be a smart ass but did you flush out the entire fuel line system of the old/bad gas? I would disconnect the end of the line at the fuel rail and run the pump for a few minutes. Get all that old gas out of there.

[Ryan86]

Just looked at my car. relay position 1 is a BMW part 12631742690 "Salmon Red Multi-Purpose Relay".
relay position 2 is a light green relay with part number 61368373700. This appears to be the fuel pump relay? Next step would be to jump the power terminals in the #2 relay "block" and see if the fuel pump turns on. If yes, then you know position 2 is fuel pump. Then make sure you have the correct part number relays in position 1 and 2.

- - - Updated - - -

Thanks for the help with the relays.

On the "no start" issue, not to be a smart ass but did you flush out the entire fuel line system of the old/bad gas? I would disconnect the end of the line at the fuel rail and run the pump for a few minutes. Get all that old gas out of there.

I drained everything up to and including the fuel filter while I had the fuel pump and level sending units out, but there was no pressure in the rail. My assumption was that what little was in the lines should get cleared out in a few seconds of operation. There's definitely pressure now, and it smells fresh when I squirt some out from the rail. Plugs are dry after cranking, so I'm leaning towards the injectors.

Ryan

[jhott66]

I drained everything up to and including the fuel filter while I had the fuel pump and level sending units out, but there was no pressure in the rail. My assumption was that what little was in the lines should get cleared out in a few seconds of operation. There's definitely pressure now, and it smells fresh when I squirt some out from the rail. Plugs are dry after cranking, so I'm leaning towards the injectors.

Ryan

Sounds like you’re on the right track.
Do you have good compression?



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[Ryan86]

Sounds like you’re on the right track.
Do you have good compression?

No compression test (yet), but the car ran strong when we put it in storage. Will tackle compression test and the valve cover gasket once it's running again.

Ryan

[Ryan86]

Sounds like you’re on the right track.
Do you have good compression?

Compression is good. The fuel injectors were the issues - as soon as I installed the new ones, it fired right up with no smoke, stumbling or hesitation!

[shogun]

Had a similar case on an E32 750 which sat for several years, the gasoline color turned to rust like, fuel pumps, filter and injectors clogged, even the FPR was not working properly.