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Re: FI Computer

> I have a very nasty problem with the Fuel Injection on my '71
> Square: the #2 injector doesn't receive signal from the computer. 
> I checked and rechecked the wires, boots, I made sure the injector is OK,
> so I'm now convinced that there's something wrong with the computer. I
> have some skill in electronics and I seriously consider the possibility to
> open the its box. However, I don't have an electric diagram of the
> computer. I have the Probst's book, but it's rather general and it's not
> of much help. What I found reading it is that the injectors are triggered
> in pairs and as #1 injector seems to work properly, I think that the fault
> is at the power amplif. level.

#2 is triggered together with #3 (and 4 with 1.)  This makes sense 
once you remember that the firing order is 1 4 3 2.  I think you will 
find that the "hot" wires to 2 and 3 are fed from a common connection 
in the brain, so if 3 works it cannot be a brain problem.  As I 
recall, if you pull the connector out of the brain you can see that 
the same PC board land feeds the pins for both injector hot wires.

The more common problem here came when Bosch introduced new
injectors in the 70s that used connection pins that were just a
couple of thousandths of an inch thinner than the originals.  This
leads to bad connections at the injectors.  The fix is to carefully
remove the female pins from the connector blocks and VERY CAREFULLY
squeeze them slightly more closed.  DON"T GET CARRIED AWAY OR OVERDO
IT!  Then they will be snug and make good connections on the injector 

71 is probably the best year of the FI era for overall realibility 
and performance.  My favorite year.  Well worth getting in shape.

> 	Could anybody help me with the electric diagram of the computer? 

Never seen one.  If you find a source, I'd be VERY interested.

Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA

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