[Vwdiesel] runaway/blowby

Shirley, Mark R MarkRShirley at eaton.com
Mon Feb 28 09:49:12 EST 2005

On most automotive pumps, the fuel ring is not directly connected
to the accelerator lever.  If it was, you could do smoke screens on
demand.  It's tied to the rpm governor, and that's tied to fuel pressure
among other things.  

My 6.9 acts exactly like this when it's running out of fuel...
which it does a lot of with no fuel gage.

> -----Original Message-----
> From: SLATERSFB at aol.com [mailto:SLATERSFB at aol.com]
> Sent: Monday, February 28, 2005 9:43 AM
> To: vwdiesel at vwfans.com
> Subject: [Vwdiesel] runaway/blowby
> Internal pump pressure goes down, allowing the fuel ring to move and
> add a bunch of (non-existant) fuel.  When it gets another 
> slug of fuel,
> the springs can't dial it back fast enough, and the engine races for
> a second.  It's a governor issue.  Just don't run it out of fuel.
>                        ******************
> OK, I just had one of these pumps completely apart & as far 
> as I can tell, the governor is there only to limit top speed 
> & doesn't come into play at all til then. Correct me if I'm 
> wrong. Also, at idle, the fuel ring is at rest. Lowering 
> internal pressure would have no effect on it. My experience 
> with air leaks in VW diesels is that they just stutter & 
> quit. Dead miss sometimes. I've nevr experienced any racing 
> or runaway symptoms. GM pumps may be different; not sure.
> Bob in NY
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