[T3] Fuel Pump Relay - 69 Fastback

[William Jahn]

I was going to suggest checking the pump fuse because a voltage drop like
that sounds like a possible fuse issue. You can check for voltage drop with
a voltmeter ground the meter to a good ground and touch the red lead to
each side of the pump fuse while you turn the key on . Also if you have a
DVOM with an amp meter set it on amps most will support 10 Amp, remove the
fuse and connect the meter at both fuse contact ends , this will tell you
what the pump is drawing . It's difficult to say what part of the pump
relay failed, meaning the coil or the contacts of these relays seem to last
a good long time. If I recall the pump draws around 4 amp .

 On the Samba the VW site there are all sorts of issues like you have and
what was needed to fix them. You can search type 3 fuel pump .

 As Jim said there is a lot more that can cause it not to start.

On Fri, Jul 9, 2021 at 10:48 AM Tim Schiller <schillertim at comcast.net>
wrote:

> I will follow the ground and check the fuse
>
> I did hook a reliable 12V to the red wire going to pump. Pump buzzes loud
> and clear.
>
> I had purchased 2 relays and swapped just in case one was bad, but same
> results
>
> Sent from my iPhone
>
> > On Jul 9, 2021, at 10:35 AM, Jim Adney <jadney at vwtype3.org> wrote:
> >
> > Tim,
> >
> > 86 should get 12 V from the main relay as long as the key is ON.
> >
> > 85 gets grounded by the ECU for ~1 seconds unless the engine is turning
> > over. If the engine is turning over (or running) the ECU keeps this
> terminal
> > grounded.
> >
> > 85 & 86 are the connections to the relay coil, so the relay should close
> and
> > send 12 V to terminal 87 for ~1 second after the key is turned ON or as
> long
> > as the engine is turning over or running.
> >
> > Check the fuel pump fuse carefully. Sometimes the fusable link can break
> > but still look good.
> >
> > 87 is the power source for the fuel pump. It should have 12 V on it as
> long as
> > there is 12 V from 85 to 86. Follow that red wire to the firewall and
> find a
> > brown wire that comes along with the red wire from the pump. The brown
> > wire is the fuel pump ground.
> >
> > It can be helpful to get someone to listen down by the RF tire, to see
> if they
> > hear the fuel pump buzz. It should always buzz for that first ~1 second.
> >
> > On 68-70 cars that brown wire goes to ground via a rather torturous
> route. I
> > make a very simple $10 kit to greatly improve the reliability of that
> ground,
> > but I need your VIN to get you the right kit.
> >
> > If you're not getting full voltage from the pump relay, try a small
> jumper wire
> > from a reliable 12 V source to the red wire to the pump.
> >
> > There are lots of possibilities for why your car won't start. Check to
> see if the
> > pump is running. If it's not, continue checking out its power source,
> both 12 V
> > and ground. If those are okay, the problem could still be in the pump. I
> > rebuild them, but that starts to cost real money.
> >
> > Stick with this and keep us in the loop. We all want to see you get this
> > running nicely.
> >
> > Jim
> >
> >> On 8 Jul 2021 at 22:07, Tim Schiller wrote:
> >>
> >> Car had been running well until it would not start. It initially
> started but sputtered, then nothing. I did not try to start again for about
> 4 month´s. I tried again, it started, I washed, waxed and went to fill up
> before a show. After waiting 3 1/2 hours for a tow at the gas station, it
> hasn´t started since. I tell this story only for background leading up to
> my question.
> >>
> >> Tested Fuel Pump Relay and no power to the 87 pin for the 1-1 1/2
> seconds when key is turned. The 86 pin has 12V when key turned and 12V to
> power relay under back seat.
> >>
> >> I tested fuel pump directly and it appears to work fine when it has 12V
> >>
> >> Replaced Furl Pump Relay and I get power to the 87 pin for the 1 - 1
> 1/2 seconds. Car still doesn´t start. Check voltage to 87 pin again and I´m
> only getting about 5V for the 1-1 1/2 seconds. Should I be getting 12V? If
> I should have 12V, suggestions on why I not and what I should check next?
> >>
> >> Any help is appreciated
> >>
> >> Tim
> >>
> >> Sent from my iPhone
> >> _______________________________________________
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> >
> >
> > --
> > *******************************
> > Jim Adney, jadney at vwtype3.org
> > Madison, Wisconsin, USA
> > *******************************
> >
> > _______________________________________________
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>
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