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Euro E30 320i: Fuel Not Reaching Fuel Rail

Discussion in 'E30 (1984-1993)' started by BMWtyro, May 22, 2012.

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    BMWtyro

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    After many repairs to my 6/83-built Euro 320i including replacement of all fuel hoses (BMW Genuine) and filter (Bosch), I am getting no fuel to the fuel rail; this is a new development. The fuel relay clicks and the pump seems to hum when the engine is cranked, but I have disconnected the fuel hose at the "tee" near the rail and no gasoline reaches that point.

    The crank position sensor is in place, and don't believe that it is possible to wire the fuel pump backwards (power lugs and eye terminals are different sizes). However, I am a bit afraid to use Bentley's instructions for testing this system's electrics as Euro are wired differently from U.S. models.

    The cause is obviously something which I did (or didn't do) while working on the car . . . but what? Any suggestions?

    Jeff Dreibus
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    MGarrison

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    Presumably yours has the in-tank pump - is that working, as well as the external pump? I recall having a crank position sensor where the wires were broken internally - perhaps check that? The pressure regulator in theory isn't an issue if you're not getting gas that far. Any chance of a clogged hose/line? Motronic has a fuel relay and a main relay, I'm guessing yours is L-Jetronic? Check the main relay too assuming it has one? Jumper the relay(s) & see if that gets an fuel moving? (Bentley manual has instructions for that). Try sending an email to Mike Miller (Roundel Tech Talk), he may have some answers for you that steer you in the right direction - good luck!
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    BMWtyro

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    MGarrison,

    Thanks so much for all of the good suggestions. As it turns out, it was a non-functioning in-tank lifter pump. Once I primed the primary pump with gasoline, it started right up and is running fine. It is amazing that the entire purpose of the in-tank pump seems to be to prime the other pump.

    Jeff
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    MGarrison

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    My rather-vague-at-this-point recollection is that BMW found during development that the primary fuel pump wasn't adequate and had to add the in-tank pump to ensure fuel delivery - glad you worked it out and it was something straightforward. :)

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