[T3] sputtering and bogging down update

Jim Adney jadney at vwtype3.org
Fri Oct 24 10:20:17 PDT 2014


On 19 Oct 2014 at 12:46, Chris Sheridan wrote:

> I did just run a test where I routed the fuel pressure gauge up to the
> drivers seat and repeated the symptoms by driving the car around - same
> symptoms of bogging down and choking/loss of power on the hill and
> symptoms to a lesser extent on level ground toward the top of the rpm
> range. During the whole test the fuel pressure was at 28 ft pounds.
> There was not change at all in the fuel pressure when repeating the
> symptoms. 

If the pressure never droops, the pump is delivering all the fuel 
that is needed. You've cleared the pump as a suspect.

> I looked at my flaps guage and they are showing that they are opening,
> though not quite as far as when I had on two springs. Car does seem to be
> running a bit hot after only 10 minutes, though my flaps are definitely
> opening so I don't want to write off the overheating to just the flaps,
> something is telling me there is a 2nd cause which is causing the hot
> running and bogging down.

This does not sound like a flaps problem. I believe your cooling 
system is working properly, assuming your cooling air intake bellows 
is in good condition so that only COOL air can be sucked into the 
engine.

> What does the vacuum pressure sensor do? someone mentioned checking
> that. I have another used one to swap in, but is there a reading I can
> take on the one in place first? 

The pressure sensor measures intake manifold pressure and the FI uses 
that info to decide how much gas to inject. You can attach a clean 
hose to its vacuum port and suck on it to see if it holds vacuum. It 
will either hold vacuum for at least a few seconds or you will find 
that you can suck forever and never get a vacuum. The latter is a 
failed pressure sensor. There are also resistance checks, but those 
almost never go wrong.

You should also look at the adjustment screw on the end of the PS. If 
the OE epoxy is still there then it's not been tampered with. If it's 
been "adjusted" then all bets are off. I can readjust it for you, but 
you can't do this job yourself.

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