[T3] car died on way home
spinningrooves at gmail.com
Fri Apr 6 19:38:14 PDT 2012
Here's the latest. Got the volt meter out. Turned key, got 14v out of the
FI relay under the dash. Started the car. Ran fine for 30-40 seconds, 14v
still coming out of relay... then voltage dropped to zero INSTANTLY. There
was no gradual decline in output voltage. Engine died. When I did it
again, same thing happened and I felt the relay click off thru the probe I
was holding on the terminal.
So, is the relay clicking off due to the relay being bad, or is the
supplied voltage going to zero and thus the relay opened? By supplied, I
mean the voltage that, when present, trips the relay to output 12v.
I'm kind of puzzled as to whether the relay is actually causing this
- Bryon, '71 Fastback FI/MT
On Mon, Mar 26, 2012 at 7:14 PM, Jeremy Menzies <skellzangelz at hotmail.com>wrote:
> I had a similar problem about a month ago. I went to start the car after
> work and it would turn over but not fire (and it ran fine driving to work).
> I noted that my relay wasn't clicking with the ignition turning on, so I
> rigged up a jumper wire to run the pump constantly and drove home. A day
> later, I got an inexpensive 40amp auto relay from radio shack for like $5
> just to test and eliminate the relay and it solved the problem completely.
> Maybe that could be a quick test for you to try? At most you wind up with
> a spare relay floating around and you can still get the real Bosch one from
> I also have a '71 and was frustrated by the same lack of detail of the
> actual pump relay wiring, which it just doesn't show. I spent a while
> trying to figure out what wires were what before I tried the new relay. I
> think that on relays in general terminal 30 is voltage in, 85 is ground, 86
> is to the ignition switch, and 87 is voltage out (to pump). You could try
> connecting the lead from 30 to 87 and see if the pump runs to determine if
> the relay is bad. Anyone correct me if I'm wrong on this, of course.
> SF, CA'71 Squareback, MT, FI
> > From: spinningrooves at gmail.com
> > Date: Fri, 23 Mar 2012 21:03:33 -0700
> > To: type3 at vwtype3.org
> > Subject: Re: [T3] car died on way home
> > >
> > > >>>> The 3 wire connector is for the backup lights.
> > >
> > Ok, feeling pretty silly now!! But I have trouble following the wiring
> > diagram in the Bentley for my year (71). It just shows the FI power
> > relay and has a wire heading off the page which then says "Connection to
> > fuel pump relay" but doesn't show the wiring. For 72 and on, the diagram
> > is a little better but I didn't know if it applied to me.
> > >
> > > >>>>>The white wire is the giveaway; that's the FI wiring harness
> > > That's the one you need to check. If it's okay, I'm suspecting the
> > > fuel pump relay of getting resistive. I've seen a very few of them go
> > > bad, but more than zero. I have good ones available here.
> > How much would you like for a working relay?
> > > >>>>>>The primer bypasses the relay. Unless you hear the relay click
> > > just before things start to go bad, the relay must be your problem.
> > >
> > Hmmm....not sure about this. But I'd like to check the voltage like you
> > said you did. Which terminal is the output ? Again, my wiring diagram
> > not helping me too much. Would it be terminal 87 ?
> > Thanks for helping to narrow this down...
> > - Bryon, '71 Fastback FI/MT
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