4kq hard starting-stumbling

Huw Powell audi at humanspeakers.com
Wed Jun 22 18:57:05 EDT 2005

> I've been having a problem w/ my '85 4kq lately that I
> can't seem to figure out.
> Problem:  Hard starting when "cold"-- cold varying
> from 50F to 95F.  Car will sometimes catch when key is
> first turned, but then stalls.  After a few attempts
> the car will eventually start, but will have trouble
> idling for about 30 seconds- usually need to keep the
> revs above 1500RPM during this time - then the idle
> evens out and I can drive away.  Once car is warm, I
> can turn off and restart easily.  AFter it sits for a
> few hours, the hard starting begins again.
> Diagnostics/Changes so far:

> -Swapped ECU temp sensor with known good--no change

Darn, that would have been my first guess...

> -Checked after start enrichment function--ECU does
> enrich mixture after starting

You're checking it by observing the current at the control pressure 
actuator, right?  One thing you could try would be to remove the CPA and 
shoot some brake or carb cleaner through it both ways.  They do 
sometimes get clogged.  Be careful not to lose the two small o-rings.

Huw Powell



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