I had an intermittent engine hard start (and one out right stall) on
my Jetta engine swap which ended up being diagnosed by me
"accidentally" hearing a buzzing sound in the engine bay. The noise
was from a relay and if I recall, it was the main power supply relay
to the engine management. That relay used a printed circuit board. It
had a cracked solder joint. (Ironically, the fuel pump relay also had
an intermittent break at a hard wire from a pin to an internal
component. The switch coil if I recall). I also had a 99 programmable
intermittent wiper relay intermittent failure at a cracked solder
joint on the PCB. No buzzing sound but same failure as the power
supply relay and the fault could be consistently triggered by gently
moving the wires at base of the relay.

A mechanics stethoscope may be your friend here? Or a long screwdriver?

On 7/16/17, Richard Koerner <rjkinpb@sbcglobal.net> wrote:

> But, heard some intermittent buzzing in Fusebox area around left driver's
> knee area.  Hmmmm...  Temperature gauge fine, engine performance fine..just
> the buzzing in fuse panel area.  Intermittent....this may be a key clue.
>

--
Neil n

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