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Re: [T3] (not) starting on 1970 FI


On 2 Jul 2003 at 7:41, Big Al wrote:

> Jim Wrote:

> >If you're sure that you can actually hear the pump spinning, then you should
> >hear 2 clicks and notice that the pump only runs between the 2 clicks.
> 
> I'll have to listen again.  I didn't know about the *2* clicks...

Yes, when you turn the key ON (not START) you should hear an immediate click 
and then a second click about 1 second later. The fuel pump should run ONLY 
between these 2 clicks. If the pump runs all the time the key is ON then 
something is miswired.

> >It might make sense to unplug the FI trigger point wire
> >from the side of the dist and check the resistance between the center terminal
> >and each side terminal in turn. Each way, you should see the resistance toggle
> >from zero to infinity as you crank the engine with the starter.
> 
> OK, I'll do that.
> 
> To make sure i understand...   I'm testing ohms between terminal 1 & 
> 2 and between 2 & 3 on the FI terminal on the Distributor.  there is 
> no chance of damage to the brain doing this test, right?

Yes, that's the right test. Right, no chance of damage to the brain. You're 
measuring the distributor contacts while the brain is at the other end of the 
wiring harness

> What are these terminals telling the brain? (I am assuming that these 
> are not power supplies, but sensors since the wires are so thin 
> gauge.)

There are 2 contacts in there, with the center terminal in common. Each one 
tells the brain WHEN to trigger a pair of fuel injectors. #1 & 4 get triggered 
together and then #2 & 3.

If one of the contacts gets some dirt in there the whole system usually just 
shuts down. Others report that some years seem to continue to run on 2 
cylinders, but I've never seen this. It appears that the electronics is 
(usually) set up so that triggering one side also "resets" the other side and 
without a reset the other side won't go even if triggered.


-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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