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On 31 May 2005 at 21:43, Matthew Jones wrote: > My FI fuel pump relay failed a few weeks ago. It started clicking a bit while I > was driving, then whirred for a few seconds, then went off. After a few > attempts to restart the car I gave up. I was near home so I got a lift home for > a few tools - the few I didn't actually have in the car at the time, of course. > Thanks to a great deal of lurking on this list I immediately knew what the > problem was, and that all I had to do was bypass the relay and hey presto, > trouble free drive home. So thanks everyone for helping before I even had to > ask. > > I took the relay out and tested it with a spare battery, and it seems fine. I > can get it to whirr by gently touching the battery leads to it, but that is to > be expected. The relay should just click, not whirr. If it is actually buzzing on you then there's something intermittent in it. OTOH, if you're hearing the fuel pump whirr when you power the relay then that's okay. > If it's not the relay itself, what is the next most likely cause of it whirring > - my guess is the FI power relay ? No. If there was a problem with the FI main power relay, then jumpering the fuel pump relay would still leave you with a partially lame FI system. You should check the wiring that controls the pump relay, especially a splice connector in the engine compartment. It will be right up at the front of the compartment, just to left of center. If that connector has been taken apart and then not put back together well, then this could be intermittent. > If I need to replace it I assume a standard 12V SPST relay will be fine? The > fact that the original has a special 311 part no and is a funny shape is not > relevant? The tag numbers are the same as almost any other relay. While any decent 12 V relay would work there, it's probably worthwhile getting the exact right part, simply because the 2 wires which control the relay (85 & 86) are in a white plastic holder that insures that they can only be connected one way. If you used a generic relay and happened to connect it incorrectly at some point, there's a chance that you could destroy the FI brain. A good used one should not be hard to find. > While I was poking around under the dash, I noticed that of the wires from the > FI to the relay, the 2 which switch it are there (grey to 85 and blue/yellow to > 86), but the red one has been cut. According to my Bentley this should be > current track 5, going to the ECU. Is this going to be a problem? The car seems > to be running fine. There should be 3 red wires: 1) from the fuse box 2) to the fuel pump 3) to the aux air reg on AT cars. This wire may be cut off on MT cars. -- ******************************* Jim Adney, jadney@vwtype3.org Madison, Wisconsin, USA ******************************* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~