[T3] 71 Squareback MT/FI - Intermittent Engine Stopping

Jim Adney jadney at vwtype3.org
Fri Jun 12 13:48:58 PDT 2020


On 12 Jun 2020 at 15:04, Wisconsin Spryers wrote:

> While driving around the block this morning, the engine stopped
> and it didn't restart. I held down the primer switch and the engine
> still did not start. In addition, I did not get the 2 clicks from the
> Fuel Pump Relay - only 1 click under the rear seat. After about 1 hour
> tried again...same results: No clicks from the Fuel Pump Relay, 1
> click from under the rear seat, engine not starting. I removed the
> Fuel Pump Relay (Bosch, Made in Germany, VW Part No: 311 906 061) and
> around the center terminal (labeled 30/51) there is some
> dis-coloration - blackish color. Bad Fuel Pump Relay? Any other tests
> I can perform?

If you don't get 2 clicks, there's definitely a FI problem. Did you EVER get 2 
clicks? If not, you may have a wiring problem that is keeping your fuel pump 
running any time the key is ON. If you're only getting 1 click, make sure the 
pump isn't running at all with the key ON.

You say you held the primer switch DOWN. You should be pulling it toward 
you, unless you have the switch installed backwards. Toward you should be 
the momentary, spring-loaded, direction.

If you were actually doing the right thing (pulling against the spring) then this 
should have run the pump in spite of any other problem. In that case, it 
seems likely that there is a problem with either the power or the ground for 
the FI brain.

The brain gets its power via 2 wires that run rearwards from the main power 
relay under the back seat. First, make SURE that the large red wire from the 
battery + to the power relay is connected at both ends. Then make sure that 
the 2 wires leading rearward out of the relay are both in good condition.

If that looks okay, go to the engine compartment and look at the far forward, 
left corner of that space and find 2 wires that come out of one harness and 
connect to 2 white wires that go into the FI harness. Those are the 2 power 
wires that feed the brain. They both need to be there and connected 
properly.

If those look good, look to the left of the breather stand on the engine. There 
will be a 3-lug ground connector there with 3 connectors (6 wires) plugged 
into it. Verify that they are all tight. One of them is the ground for the brain. 
There may also be another ground connection on the case that you should 
check at the same time.

Let us know what you find.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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