[T3] Perplexing hesitation/stumble/stall

[Jim Adney]

On 6 Feb 2012 at 10:40, Norman Roush wrote:

> My '68 Sqbk with stock FI and MT is driving me crazy with an
> intermittent hesitation/stall.  It will start and idle OK.   Halfway
> into my 20 min commute it often feels like it is missing on 1 or 2
> cylinders. Sometimes it bucks like engine quit then starts again
> immediately and sometimes  it stops altogether.   After it stops I
> check all the connections on engine and have gotten it running every
> time.  Sometimes I pressed the accelerator peddle all the way to the
> floor to get it going.  It doesn't seem to be bad gas or water in gas
> as it runs well most of the time.  It seems to be heat related.  I had
> it running last night and wiggled all connections in engine bay I
> could see but no hesitation, no stall.  This morning it was stumbling
> again. 

Like Bob says, check the system voltage and replace the VR if the 
voltage is below 13.5 V at the battery with the engine warmed up and 
the engine running at med RPM.

Other possiblities:

Could be worn or dirty trigger points, which would benefit from a 
distributor overhaul.

Could be a loose screw holding the FI main power relay under the back 
seat (if you hear relays clicking when this happens.)

Very likely the ground screws for your '68 fuel injectors are losing 
a good connection to ground. There is a ground screw on each head 
('68-9 only.) These lose contact as the head warms up. Tightening 
only helps temporarily. I have Belleville washers to go under these 
screws to make a very cheap, but permanent, fix.

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