1984 4k - no start

Huw Powell audi at humanspeakers.com
Sat Sep 19 16:14:01 PDT 2009

> Well the car starts and runs. After its warm though, it no longer
> starts. Today it would need to sit for just a few minutes before it
> started again.

This is common issue which Audi altered quite a few things over time to 
"prevent".  It could be a combination of a faulty fuel check valve 
(letting pressure drop) and heat soak at the head, vaporizing fuel in 
the injector lines.  Can result in long cranking, or even no-start until 
things cool a little.

Heat buildup has also, IIRC, been implicated in intermittent Hall 
senders on the dizzy.

> While running, I can tell it isn't running well on the low end.

Might be a completely different issue.

> For the no-start the O2 sensor may make sense as it seems to have
> trouble after warm up.

O2 sensor not used while starting.  Easy to test when warm running, 
though - voltage should cycle up and down between about .3 and .7 volts 
DC every few seconds.

> For the not running well - I'll take a shot at the DPR.
> Now to your comments - I thought the DPR was the assembly directly
> over the fuel meter arm sitting on top of the airbox. Which is the
> fuel distributor?

The DPR is the little grey box on the front of the fuel distributor with 
an electrical connection.  Two bolts hold it on; there are two small 
o-rings to make sure you don't lose (or have new on hand).

Have you made sure *all* the electrical connections (especially CIS ones 
of course) under the hood are clean?

Huw Powell



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