Fuel Fuel Pump Power Issues - No Power at Pins 37 and 57 on EEC

[NoBikeMike]

I've inherited a yardfind 91 5.0 and am running down a fuel pump issue.

I'm getting 6v at the inertia switch all the way up to the EEC relay. Fuel pump and EEC relays are new. At the EEC, I'm getting good grounds and constant 12v power. I am, however, not getting power to pins 37 and 57. But, I can't find out what feeds these wires power.

This is a 91 5.0, so there's no ICRM/CCRM. What's the next thing to check? Ignition switch? Car turns over, starts with starter fluid, relays click, but power remains 6v at the rear. Jumpin the diagnostic port gives me 14v at the inertia switch/fuel pump.

Thanks for any help!

 

[Blown88GT]

EEC Power Relay or Fuselink G.

p.33

1988 Mustang Electrical & Vacuum Troubleshooting Guide (EVTM)

File is too large to upload. Here is link to it on my Google Drive. View: https://drive.google.com/open?id=1on5czXKmpETzxUggWTGtoUuVkJT2UUxN

www.stangnet.com

 

[KRUISR]

I had issue with my fuel pump kicking out intermittently. It was the plug in the driver side kick panel. The pins had gotten loose and were not making consistent contact. It would work great and then bump the kick panel cover with your foot and fuel pump would kick out. When kicked out I would not get power to the fuel pump relay (under seat in my case - located between kick panel and fuel pump).

 

[NoBikeMike]

EEC Power Relay or Fuselink G.

p.33

1988 Mustang Electrical & Vacuum Troubleshooting Guide (EVTM)

File is too large to upload. Here is link to it on my Google Drive. View: https://drive.google.com/open?id=1on5czXKmpETzxUggWTGtoUuVkJT2UUxN

www.stangnet.com

EEC Power Relay is new.

And, I've got 12v power to the relay (black and orange wire) and 12v when jumping the EEC diagnostic port. Wouldn't that mean that the fuse link is good?

 

[Mustang5L5]

Pin 37 and 57 are fed from the eec power relay. If you have no power there, then either wire 37 from the fuse link is dead (you can check at pin 1 on the ecu), or the eec relay isn’t being triggered.

this is the ‘91 diagram