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A4 fuel system (electric pump)

Posted: Sun Jan 21, 2007 7:43 pm
by Figment
There is nothing terribly complex or challenging about replacing the A4 fuel system. It's mostly about the checkbook. I have better access to that side of the engine than many people, though, so maybe these pics will help those folks visualize what their fingertips are telling them.

A key safety feature of the electric fuel system, of course, is the oil pressure safety switch. For a number of reasons, the best place to locate this device is at the port just above the pressure regulator.
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In most cases, that port is plugged with a flathead screw that is quite securely rusted and painted in place. Even with my wide-open access on that side of the motor, I couldn't get an impact tool on it. I'd been soaking-and-tapping with PB Blaster for a couple of weeks, so I was fortunate enough to be able to break it loose with a pair of vicegrips. HUGE VICTORY.
If it can't go there, it has to tee-off the pressure guage sending unit tap at the front of the motor, and that's already a rather congested neighborhood.

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Moyer provides a dandy bracket which closes off the mechanical pump's drive-hole and mounts the electric pump. Mounting the pump and connecting to the carb via the polishing filter are fairly simple matters.
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Wiring the pump via the safety switch to the hot terminal of the coil is not particularly difficult. Most time here will be spent fussing with the length of the wire from the coil to the switch, ensuring convenient access to the in-line fuse. Test the connections, give them a quick shot of Boeshield, and that's that.

Posted: Mon Jan 22, 2007 4:39 pm
by jpmathieu
There is nothing terribly complex or challenging about replacing the A4 fuel system.
I installed the same setup last year. You are right its not terribly complex, and it was great getting rid of that old fuel pump. Don't be afraid.
If it can't go there, it has to tee-off the pressure guage sending unit tap at the front of the motor, and that's already a rather congested neighborhood
I had that problem with the port. I worked on for as long as I could without damaging the set screw. I installed it on a tee, It seems to have worked fine.

Posted: Tue Apr 17, 2007 12:45 pm
by Figment
When I "completed" this conversion back in January, I had no exhaust system or fuel tank, so I didn't get to test it out. This nagging little kernel of doubt has been rattling around in the back of my mind since.

Sunday was test-fire day. Wouldya believe the friggin thing fired right up in less than five seconds?
If not for the billowing smoke due to MMO fog, you'd never have known winter ever happened.
I'll still need to adjust the main jet and the idle limit, of course, but not by much.