fuel pump voltage

[Scott Feaver]

that was probably just noise
-----Original Message-----
From: Paul Raley <raleyp at UDel.Edu>
To: DIY_EFI at coulomb.eng.ohio-state.edu <DIY_EFI at coulomb.eng.ohio-state.edu>
Date: Tuesday, October 14, 1997 4:32 PM
Subject: fuel pump voltage


>I have been measuring the voltage in my fuel pump(an 86 300zx turbo) and
>found a few odd things.  The first finding was the obvious, a swinging
>DC voltage between 9-12 volts with occasional 14volt readings (can't
>figure why though, doesn't moven between 12-14 volts).  Then I switched
>to AC readings, I noticed 16volts at a frequency between 60-70khz.  The
>AC reading would sometimes fluctuate, but the more gas the car was given
>the lower the AC voltage and higher the DC voltage.
>Does the ECU convert the DC to AC to drive the pump and then convert it
>back finally into DC again?  And what is the deal with the frequency?
>Sometimes it jumps around, but I could not see any correlation to
>throttle position and frequency.
>
>Paul R
>
>