Re: Long cranking - 5000 Turbos

[charlie@elektro.cmhnet.org (Charlie Smith)]

Earlier, Thomas Tornblom wrote:
> 
> > From: glen.powell@smc.com
> > 
> >   All Audi Turbos I've had experience with seem to require a long crank
> >   time to start. All non-turbo Audis seem to start instantly. I always just
> >   assumed that it is the relatively low compression of the turbo engines
> >   that makes 'em hard to light off. Seems to be "normal" for turbo
> >   Audis.....
> 
> Another possibility is that the ECU requires some time to settle
> before it enables ignition. The non-turbos doesn't use the same
> sophisticated ECU as the turbos.
 
I suspect it's got to do with the extra heat from the turbo under the hood.
This bakes the fuel injector lines and tends to promote residual fuel
pressure in the system going lower than desired.

When I've got my CO adjusted just right, and if the fuel pump runs for
a couple seconds before you hit the key - it will start right away.
You have to jumper the fuel pump relay ground to get it to run before
the engine begins cranking if you want to do this experiment.


    - Charlie



Charlie Smith   charlie@elektro.cmhnet.org  614-471-1418  
Columbus, Ohio USA


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