[DML] Re: Hesitation from the Line

[Marc A Levy <malevy@xxxx>]

I sometimes have this problem too when the engine is cold. Was it cold
when this happened?

I suspect the problem is that with the turbos (I have twin turbos, so I
am assuming your setup is similar to mine) the cold start valve does not
work properly due to the lack of vacuum in the intake where the valve
(injector?) is located. My non-professional opinion would be that
because this extra shot of fuel is not being sucked in to the intake as
it normally should (because of the boost), the car hesitates.

I have considered relocating the tube that the valve is in to a point in
the system before the turbos. On my car there is some space between the
throttle plate and turbo inlet (This is where the vacuum for the timing
control is taken from). This should be the point of highest vacuum in
the system under all driving circumstances (boost or not). I have some
reservations about trying this, and it may be a good time to present
questions to the list to see if there are any answers-

- Is it OK to run a air/fuel mixture through the turbo? Currently no
fuel goes through the turbo and I worry that the fuel may damage the
turbo, and may even be a fire hazard.

- The cold start valve assembly also includes two barbs for vacuum for
the PCV system, and fuel vapor recovery system. Will the contaminants
from those sources damage the turbo or be a fire hazard?

- I had some others, but forget now :)


Rich Kula wrote:
> 
> This morning I noticed some hesitation in 1st gear (5 speed with a single turbo) and was wondering if someone could point me in the right direction. I had to press the pedal all the way to the floor and once it hit 2000 to 2500 it seemed normal again. Just it seemed slower in getting there. The other gears and speeds seemed fine from an acceleration standpoint. Thanks for your support.
> 
> Richard Kula
> 
> #1460