Peter writes...
> My (crude) analysis of this
>leads me to think that either I have two faulty oil pressure switches or
>something in the block where the switches connect to (an oil gallery???)
>is behaving differently when the engine is cold than when the engine is
>warm (or recently run). Could the gallery be getting plugged when warm?
>Or is something making the switch think it still has >5psi pressure when
>I shut off the engine? If so, what could cause this?
Your analysis sounds pretty much spot-on to me. The last sender I
bought for the Spit developed a definite "hysteresis" problem, to
steal one of Dan's terms. :-) It wouldn't reliably reset even after
I unscrewed it from the engine block. It was made by "Commercial
Ignition" out of the UK, BTW, less than two years young. Just now I'm
using one from my '74 Plymouth 'till I nail a genuine Lucas part.
Your idea of the oil pressure gallery staying slightly pressurized
sounds viable too. Again, I'd think you could just unscrew the bugger
for a quick test.
Finally, solenoids have a nasty habit of sticking and drawing
excessive current in the process. This could be wreaking havoc with
the contacts in the switch. I have little knowledge of the
anti-dieseling solenoid unfortunately as my was MIA when I bought the
car. Does it look like you could take it apart for inspection?
Cheers!
Tom O'Malley in Southbridge Massachusetts
'74, '77 Spits
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