85 4kq power hesitation when cold

[Russ Maki]

I'm still a few hundred miles from pronouncing the trouble "officially
fixed," but I think I've found the source of a similar problem with my '87
4kcsq. Basically, the car wanted to run lean all the time. In retrospect,
the CIS-E control unit usually compensated -- but when the engine was cold
it just didn't want to run right. The symptoms progressed to the point where
the car experienced power loss on the road. After noodling around the
ignition and triple checking for vacuum leaks I measured amperage to the
differential pressure regulator. It was way off -- 19.4 milliamps on a warm
engine

Thanks to the Audifans archives -- and a Dan S. contribution at that -- I
think I've found the answer: the long-forgotten in-line fuel filter in the
fitting between the fuel line and fuel distributor. I removed it and
suddenly the differential pressure reg was running on a much more civilized
11 milliamps. AND, I've got torque and plenty of it; previously the car was
becoming a real slug.

Guess I owe a certain mailing list a cash contribution.

I checked a spare fuel distributor I have kicking around, and that one still
had the filter too (they're supposed to come out very early in the life of
the car). It's a sturdy little device -- not at all inclined to come out
without a struggle.

HTH
Russ Maki
Ixonia, Wis.



> From: Ti Kan <ti at amb.org>
> Subject: Re: 85 4kq power hesitation when cold
> To: bradym at sympatico.ca (Brady Moffatt)
> Date: Sat, 8 Mar 2003 11:48:04 -0800 (PST)
> Cc: gottasix at netzero.net (gottasix), quattro at audifans.com
>
> Brady Moffatt writes:
> > Interesting! I guess I have a similar problem on my 86 4ksq. The car
starts
> > and idles well. It drives well when cold, but after about 3-4 minutes of
> > driving, it stumbles and has very low power. After about 30 seconds of
this,
> > all is well again and it stays fine for the rest of the trip. I think
this
> > only happens in winter. I'll let you know for sure if winter ever ends
(not
> > complaining).
>
> > From: "gottasix" <gottasix at netzero.net>
> > Unable to locate an answer to this common 4kq problem in the archive so
I
> > look to you for assistance. I have an 85 4kq with 110K, my issue is when
the
> > engine is cold; idles and starts fine, but when I attempt to take off
and
> > drive there is very little power, allot of hesitation, especially going
up
> > hills, but after 5 minutes or so, temp gauge needle gets to 4 o'clock,
the
> > car jumps to full throttle and has good power after that, like a sticky
>
> Possibly the CIS-E coolant temperature sender is not within spec.
> Also, maybe an intake air leak and basic mixture/idle/ign timing
> settings need to be tuned to spec.
>
> -Ti
> 2003 A4 1.8T multitronic
> 2001 S4 biturbo 6-sp
> 1984 5000S turbo
> 1980 4000 2.0 5-sp
> --
>     ///  Ti Kan                Vorsprung durch Technik
>    ///   AMB Laboratories, Sunnyvale, CA. USA
>   ///    ti at amb.org
>  //////  http://www.amb.org/ti/