[T3] 71 squareback fi problem/question

Jim Adney jadney at vwtype3.org
Fri Aug 11 22:29:05 PDT 2017


I don't think this is a fuel pump problem.

It could certainly be an ignition problem instead of a FI problem, so 
figure out a way to see if you actually have spark when the car won't 
start.

It sounds like your cold start valve may be working all the time. The 
extra rich mixture makes it impossible to start a hot engine. Find 
the cold start valve and the single wire that runs down from it to 
the temp sensor, which is under the Intake Air Distributor. Make sure 
that wire hasn't gotten mislaid in such a way that it's touching 
ground. You can check this by simply unplugging the cold start valve 
electrical connector, disabling it. You can leave this off if that 
fixes the problem.

Another thing to check is to get in the car and listen carefully 
while you turn the key ON. You should hear a click as the key goes ON 
and another click ~1 second later. Do you hear both clicks? If not, 
there's a wire on your starter that's been misconnected.

Any chance you've had the starter replaced or worked on lately?

Check both ends of the pressure sensor hose and make sure that both 
ends are connected. Get a yard of 5/16 hose; put one end on the 
pressure sensor and suck on the other end. It should hold vacuum. If 
it doesn't, your diaphram has cracked, making for an over-rich 
mixture.

Let us know what you find.

On 11 Aug 2017 at 23:57, Birtalan, Victor wrote:

> Hello, I have been following the current email  discussion regarding
> type3  fuel pump/ check valve functionality.  During this period my 71
> squareback, FI, developed a problem that seems related, but not an
> exact match.  The problem is that after driving a short distance, ie,
> 3-5 miles, then shutting down, I am unable to restart, although I have
> attempted to prime the system using multiple key cycles.  I can hear
> the fuel pump energizing when I rotate the key, however the engine will
> not start after multiple cranks.  However, if I allow the car to remain
> in place for several hours,  for example during the course of a work
> day, 8 hours, it will start with one turn of the key.  This has me
> baffled since I have now been stranded a few times, but luckily only
> in parking lots.  Once started the car runs, maybe a little rough, but
> it will run continuously.  So, Is this a result of a problem with the
> check valve not keeping fuel in the line for the next start, or
> something related to the fuel pump.  The tank is vented normally, and
> I have attempted to start, with no luck, with the tank cap removed. 
> Please advise if possible. 

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