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Re: Fuel Injector Question

I'm telling you exactly what I read from the Bosch:Fuel Injection book I

The problem is not when the engine is running.  It's when it isn't.  The
older, CIS and EFI injectors had the valve too close to the engine
block and the fuel would get hot enough to decompose and clog the
injector's seat with deposits  causing it to leak and not fire properly.
The fan keeps the injector, and the fuel inside, from heating up too much.
Later EFI injectors has the whole valve assembly moved back, and this
change happened right around 83-84 I think.


On Thu, 1 Apr 1999, Ti Kan wrote:

> Brett Dikeman writes:
> > The older CIS injectors had a design which put the rubber seal very close
> > to the engine and hence it could overheat.  The injector cooling fan
> > completely compensated for this, I believe...
> I don't think the injector cooling fan serves that purpose.  It is there
> to reduce underhood temperatures near the injectors after shut-off, to
> prevent vapor lock and hard starts.  It is controlled by a thermo switch
> which normally doesn't kick on while the car is moving.
> -Ti
> 96 A4 2.8 quattro
> 84 5000S 2.1 turbo
> 80 4000 2.0
> -- 
>     ///  Ti Kan                Vorsprung durch Technik
>    ///   AMB Research Laboratories, Sunnyvale, CA. USA
>   ///    ti@amb.org
>  //////  http://metalab.unc.edu/tkan/
> ///