[T3] 1970 Fastback FI won't start

Jim Adney jadney at vwtype3.org
Fri Feb 16 15:34:20 PST 2018

On 16 Feb 2018 at 10:26, William J wrote:

>  I've never heard the power relay click . I do hear the fuel pump relay 
> always have.
>  I wouldn't go by hearing clicks .

Listening for the 2 clicks, coming ~1 second apart is a really important 
diagnostic tool. If you don't hear both clicks, you know that there's something 
basic wrong with the FI system. It gives you a starting point for 

If you don't hear any clicks, you know that there is either a problem with 
power to the brain or the wiring between the brain and the relays.

If you hear the first click but not the second, you know that there's either a 
problem IN the brain, or in the wiring to the pump relay, or someone has 
bypassed the pump relay.

If you do hear both clicks, you know:

The brain is getting power.

The brain is telling the fuel pump relay to close and open, so at least part of 
the brain is working.

If you hear both clicks, but the engine still won't run, you know that you don't 
need to check those things.

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

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