[T3] no start -- but just drove it!

Jim Adney jadney at vwtype3.org
Sun Feb 12 09:33:46 PST 2012


On 12 Feb 2012 at 8:49, Bryon Garvin wrote:

> * Car is MT, not AT
> * Wire from ignition to starter is disconnected (I don't get 12V at
> that wire so that's one issue)
> * I have a jumper from starter to (+) battery post to take the place
> of that wire
> * Turn key to on position

And idiot lights come on, right?

> * Run fuel pump via Jim's switch for 30 seconds
> * Touch jumper to (+) battery post
> * Starter run but car won't turn over

Comment: "Turn over" is what the starter is doing. It refers to the 
early days of crank starting, when you would "turn the engine over" 
one half turn at a time with the hand crank. I suspect you mean that 
the engine is turning over, due to the starter, but it's not showing 
any signs of life. "Turn over" and "crank" mean the same thing.

> So either I have a 2nd problem, or I just didn't try it long enough
> since the car has been sitting.

You could try pumping the throttle a few times with the ignition ON 
and the pump is priming, as that will clear air out of the injectors 
and the side branches of the fuel ring.

> When does the fuel pump start to run on its own?  How does it get
> turned on when the engine finally is running on its own?

The circuit in the brain that turns the fuel pump relay on gets 
"refreshed" as each of the FI trigger points opens. That circuit will 
stay active for ~1 second after each refresh, so it will stay active 
as long as the time between trigger point openings is less than 1 
second. 

You could check your trigger points with an Ohmmeter. Check that the 
resistance between the center terminal and each of the side terminals 
goes up and down while you turn the engine over with the starter. The 
brain expects the trigger points to alternate, so if only one is 
making contact the refresh circuit won't work.  

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