[T3] Old Type IIIs (Exhaust Tester)

[Jim Adney]

On 4 Mar 2011 at 12:21, J. Jonik wrote:

> So, If I find a garage that has Exhaust Tester, and if there's a
> little too much fuel, can this be easily corrected by lowering the
> Fuel Pressure adjustment?  My fuel pressure is a constant 29.  Should
> I adjust to 28...which is what's needed anyway?  Can that one fuel
> pressure point make a noticeable difference? 

One psi probably won't make a noticable difference, and trying to 
correct a fault in an unknown area by tweaking the most convenient 
knob isn't likely to get you where you want to go. I understand that 
it's tempting, but keep in mind that each of the parameters that the 
brain uses to determine the fuel delivery has a different effect on 
the output. You can't use one to compensate for the other. You might 
get it to work well under certain circumstances, but then you might 
find that the temperature dependence (for example) was no longer 
correct.

You really have to find the root problem and correct that.

>  Car's still running (and idling and starting and accelerating)
> alarmingly perfectly.   I'm not used to that. 

Sounds great so far, and it's possible that you've fixed most of a 
number of problems. You've clearly made a lot of progress, but don't 
be tempted to alter one thing to make up for a difficulty in 
something else.

To take another example from a recent post on steering gear play, 
consider the fact that the play in the steering is made up of the sum 
of the play in a series of parts. If your wheel bearings were 
adjusted too loose, it would be a big mistake to tighten up the 
gearbox in an attempt to cure that play. It's true that you might be 
able to reduce the overall play that way, but it would leave you with 
loose bearings, which is hard on them, and an overtightened gearbox, 
which is very hard on it.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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