I am trying to diagnose my 90 f-bird's problem. I have so far narrowed it down to the relay. There is no clicking noise from the relay, even after I replaced it. I have searched the boards, bu I'm still not sure which wire send power to the relay. If the relay is not working, the fuel pump won't come on at all, right? I've checked all of the fuses and so far I am lost. Any help would be MUCH appreciated.

Also, could my ECM be fried, and how can I tell?

 

Have you checked the 20 AMP fuse located near the battery?

 

<B><CENTER>
If your ECM is defective or has a
bad connection your relay
will not function. Connect a voltmeter
to pin A1 at the ECM. Then turn ignition
to the run position. You will see a
voltage on A1 for two seconds if the
circuit is good up to that point.
</B>
<P>
<TABLE BORDER=9 CELLPADDING=18
<TD BGCOLOR=black WIDTH=60><B><H3><CENTER>REFUSE
.TO
.LOSE</TABLE></CENTER>

 

The fuse was fried, I replaced it first, then the relay. What makes me think it may be the ECM is that the oil pressure switch should still tur on the pump after cranking for a few seconds. Since the switch is wired in parallel to the relay, maybe its not getting power from the ECM. I will check A1 with a voltmeter tomorrow.
Where's A1?
I'll do a search.

 

On your vehicle it wouldn't do you any good to check voltage at pin "A1" of the ECM unless you have a 305 TBI. That would be the fuel pump relay driver for that vehicle and would be the green/white white wire going to pin "C" of the fuel pump relay. On the 3.1L, 5.0L & 5.7L TPI models it would be the wire going to pin "A11" of the ECM. It would be easier to check for voltage at pin "C" of the fuel pump relay than digging into the ECM wire harness. Another question here, have you by any chance checked the ground wire at the back of the cylinder heads?