cold start weirdness
audi at humanspeakers.com
Sat Jan 17 17:55:22 EST 2004
> I dont understand why leaky injectors would cause this problem. Are you
> saying that residual fuel pressure is the problem . .the injectors bleed off
> the pressure over time?
> If you turn ignition on, but dont start the engine. Does'nt the fuel pump
> pressurize the system?
No... although, yes, the fuel pump typically kicks on with these cars
for a second or so, it is *not* a feature, it is a bug. As Ti, I think,
pointed out a few months ago, it's a by-product of the coil connection
to the FPR telling it to run/not run depending on whether the engine is
still turning and firing. There tends to be a pulse from the coil at
turn on (and off), resulting in a short burst of fuel pump operation.
It's not enough to pressurize the entire system if all the residual
pressure has bled off via leaky injectors (or a flaky check valve).
At the same time as wiring that temporary CSV controller, it would make
sense to monitor the fuel pump operation with a small light, and also to
add a bypass switch to try running it for longer, say 10-20 seconds, to
see if that relieves the problem a bit. Then properly fix whatever
makes that a temporary "fix."
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