Re: GTV-6 fuel pump not running

[Ivan Link <ivan@waverider.demon.co.uk>]

Chris Lesher wrote

> Now here's the wierd part that I could never figure out and hopefully some
> of the electrically knowledgeable folks can help out.  On my car I tested
> the p/w wire at the fuel pump and got a zero volts reading.  When I
> disconnected the p/w wire from the pump it read 10.6 volts.  This test was
> repeated many times.  What I finally did was bypass the p/w wire completely
> from combo relay to fuel pump and that wire showed 12+ volts - not to
> mention the pump now ran.  Why would the 10.6 volts get 'lost'?  does the
> pump not run without a full 12v?  and does the voltage going into the pump
> not go to ground unless the pump runs?
> 
Classic symptoms of, you guessed it, a bad connection (Doh!)

Sounds like a poor connection between the combo relay and the pump. 
This effectively behaves like a resistor in the circuit. When the pump 
is disconnected and the relay switched on you can measure 10.6v on a 
meter, as the meter only pulls a little (or very little for a good 
one) current through the circuit. When re connected, the pump will be 
trying to suck more current out past the bad connection (resistance) 
this would cause the voltage to collapse. 

Any time I read a different high value on a car circuit than what is 
across the battery I become very suspicious ! 

Cheers, back to lurk mode...

Ivan (ivan@waverider.demon.co.uk)
Leamington, UK
Alfa 75 3.0V6 America
> Error, no keyboard - press F1 to continue.
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