"Kent" > writes:

>You know, I can't tell you for sure if the tach needle drops or
>not; I'll be keeping a close eye the next time it happens.

>Is it your experience that the Hall sensor can experience intermittent,
>rather than complete failure? The Bentley Manual led me to believe that

Intermittent failure seems to be more characteristic than a total
failure from the few cars I've seen with that problem in the real
world.

The Bentley Manual is good; but it's not gospel. Much of it was
written well before the age-related issues came up.

>unless the car has completely lost spark, and will not start, the
>problem is not likely to be the Hall sensor. I will take a close
>look at the sensor and its wiring though.

The symptoms you described are fairly characteristic of an
intermittent Hall sensor dropout.

The tacho needle is the tell-tale. If the Hall sensor fails to send
pulses to the ignition module (or ECU), the coil won't be fired so
the tacho needle drops to zero.

>I like your idea of a faulty fuel pump relay; I think I'll pony up
>the bucks for a new one and see if that does the trick.

It's one of the typical "problem areas"; along with the ignition
switch that I didn't think of at the time of writing (dopey me!).

>I have checked the intake system for obvious leaks and don't seem
>to find any. I think I'll pull the bellows off the car and give it
>a good going over.

>I'll let you know what I find.
--
/"\ Bernd Felsche - Innovative Reckoning, Perth, Western Australia
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