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

NoBikeMike

New Member
Aug 31, 2003
2
0
1
Dallas, TX
Visit site
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!
 
  • Sponsors(?)


KRUISR

5 Year Member
Apr 16, 2015
680
226
63
50
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

New Member
Aug 31, 2003
2
0
1
Dallas, TX
Visit site
Last edited:

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
35,912
11,856
224
Massachusetts
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
0C377B04-3D10-406B-9615-8826BC27098D.jpeg
 
Last edited: