RE: fuel injection

[jadney@vwtype3.org (Melissa & Jim)]

>From: "Gregory M. Merritt" <gregm@engin.umich.edu>

>On Wed, 7 May 1997, Woolston Craig wrote:
>> I have a '71 Fastback and it has a inline fuse before the relay that has 
been known to pop on occasion.  But this did not cause 
>> complete FI failure, it just ran a little rich.  I believe it is was 
because the pump was NOT shutting off at idle.  I know that my '70 
>> Sqback does not have this inline fuse.  Maybe Jim A. knows it's exact 
function?
>
>Craig,
>
>	I may be misunderstanding what you meant to write; did you
>mean to suggest that the pump *should* be shutting off at idle?  It
>should not!  If the engine is running--at any speed--and the ignition
>switch is turned on, then the pump pumps.
>
>	On later U.S. models, if you lift your foot off of the accel.
>at speed, then the throttle pos'n switch tells the brain to shut the
>injectors off until the RPMs drop down to a set amount.  Were you
>referring to this in some way?

Thanks Greg, I meant to comment on this but it slipped by.

The inline fuse is not OEM.  The fuel pump is fused through one of the fuse 
box fuses in all years.

The FI fuel pump runs all the time the engine is turning over.  Some sources 
also get this wrong.  The computer doesn't fire the injectors on overrun for 
most of the US models, not just late ones.  [I was amused last year when a 
coworker was explaining to me how sophisticated his new BMW was that it 
could sense this condition and just not fire the injectors.  He was somewhat 
disappointed when I explained to him that VW/Bosch had introduced the same 
thing in the fall of '67.]

Jim
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       Melissa Kepner                                    Jim Adney
       jadney@vwtype3.org              jadney@vwtype3.org
                             Laura Kepner-Adney
                             Madison, Wisconsin
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