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How to test fuel pump relay.
#3
testing where
off car , or on car.?
on car is best. (real live testing under load, is best always)
off car is harder,
coil 120ohms.
contacts open and read infinity
12vdc applied to the coil pins, getting polarity correct. (some have clamp diodes inside the blow up, if reversed)
now the coil energizes and NO contacts read zero ohms
this is the rudimentry test.
we can do a full load bench test , too, using a large lamp.ask.

if asking for the pinout?
then the schematic above tells you which pins are which, easy. by color associations.

on car testing is even more easy
turn key to cranking, (closes for 3 seconds each keyon (not on some 89s) and full cranking and running.
relay closes. and its output pin will be 10 to12vdc. (warm whether high side, cold lower, as starter draws huge currents)
if that fails
we check for 12vdc across the relay coil cranking, if not, the ECU has issues, ask why. (or scan the ECU to see why)
keep in mind the ECU can cut fuel for many reasons.
the above is for dead fuel pumps. only. 0 PSI, or very low.
http://www.fixkick.com
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Messages In This Thread
How to test fuel pump relay. - by Zackman - 12-29-2015, 11:21 PM
RE: How to test fuel pump relay. - by fixkick - 12-30-2015, 11:00 PM

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