[Vwdiesel] Diesel Purge ..Miser's view

[Area31 Research Facility]

In my very limited experience with the VW diesel I am learning how much a
difference physically rotating the FI pump can make on engine behaviour,
fuel consumption and power output.  I am learning to tune it by engine
rattle.  No rattle, more exhaust smoke, less power, hotter exhaust system,
more fuel consumption, hotter water coolant.

Have you got the same rattle now as before?

Rob

----- Original Message -----
From: "Gavrik Peterson" <gavrik at cablespeed.com>
To: <vwdiesel at vwfans.com>
Sent: Wednesday, May 11, 2005 3:26 PM
Subject: Re: [Vwdiesel] Diesel Purge ..Miser's view


>Do you have access to a rev counter? Grab one from a
>dead truck if not. The rev counter can be used to >supplement the injector
tests to see if any have a >different effect from the others.

I agree that more instruments would help. With my history
of fooling around with electricity I have gotten used to
needing instruments to observe things that are either not
visible to my senses or too high voltage for my fingers.
But, I know that talk like this will make Hagar think that
I have gone over to the dark side.

>I'm also wondering if the refurbished/new injectors have >become more
efficient in getting fuel across so a slight >backing out of the fuel volume
screw might be required.

Not sure what all changes with rebuilt injectors. In the
case of my problem, the smoke started five months before I
finally changed the injectors. The rebuilt injectors did
not noticeably change the smoke or fuel consumption. The
interesting thing is that the injector shop reported that
3 of the 4 injectors showed poor spray pattern. This lead
me to think that the real problem is much more significant
then a poor spray pattern. It also is possible that the
injector shop was full of it.

If I correctly understand the 'fueling screw' function,
the smoke I am seeing (except at full acceleration) would
not be effected by this adjustment because the 'fueling
screw' does not change the amount of fuel injected -- only
the maximum amount.

Another thing is that I get high fuel consumption on long
constant speed freeway trips where the pump is not at full
injection volume. If the 'fueling screw' was adjusted so
that the amount injected was limited when driving on the
flat at 60mph I would have nothing left for acceleration
or hills.

>Can you really pinpoint the change... or is it possible >you just remember
when you first noticed it?

Thought I could, but my experience tells me that I can
fool myself.

My records show that when I fueled up after a trip up to
Hagars place I had gotten 49.03 mpg. This was before any
of the symptoms we are discussing appeared. On the next
fueling I had gotten 39.8 mpg which is OK for mostly city
driving. It was while driving on this load of fuel that I
noticed the smoking. After consuming this tank of fuel the
mileage was only 36.02 mpg. I had never seen anything this
low before. This change in engine behavior happened within
around 500 miles.

   --  Gavrik
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