fuel pump + cold start + hesitation on 86 4kq

Brady Moffatt bradym at sympatico.ca
Thu Nov 1 20:01:26 EST 2001

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Hello all,

I'm new to this great list, and the wonders of Audis. I love my "new" (2760=
00km) 86 4kq but it has a couple of little issues.

1) When I turn the key to ON, I hear nothing. On my VW Golf, the fuel pump =
would run for a couple of seconds. Not so on the Audi. Is this normal? If I=
 have a small pressure leak back into the tank or something, I would assume=
 the pump would build up the pressure again. Which brings me to the cold st=
art issue....

2) The first start of the day, now that the temps are dropping into the low=
 40s at night, is a real fight. It takes at least 10 seconds of cranking to=
 fire up. I can't bring myself to crank for 10 seconds at once, so this is =
spread over 2-3 tries. There is the odd stumble, then the engine grudgingly=
 starts up. I do this with my foot off the gas. If I hold the pedal to the =
floor part way through, it will backfire lightly then start.No faster thoug=
h. Once started it runs well. The idle's up slightly, good throttle respons=
e. Actually better than when it's warmed up, which brings me to the hesitat=

3)There is a hesitation/light miss/bog from idle when the engine is warm. I=
f I floor it in neutral very briefly, then I can accelerate away from idle =
with no bog. When the engine's cold, it doesn't do it.

What I've done about it and plan to do
-dumped in a can of injector cleaner
-plan to remove and clean the idle stabilizer valve
-plan to richen up the idle mixture a bit (CO screw?)

Any other suggestions?


Brady Moffatt
1986 4000S quattro


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