I have an 88, 5.8 liter auto tranny. I had the steering column lock actuator break on it, and just got done replacing it. Now though, the fuel pump is constantly on. I disabled it for now by popping the inertia switch. Any thoughts on why it's doing what it's doing now? Did I mess up putting everything back together?
Fuel Pump always on?I have a
- Thread starter Kylston
- Start date
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yo,
The actuator/switch needs to be adjusted
When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump.
Switch Pin-Out Diagram & Continuity Testing (Logic Tables in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) Source: by Broncobill78 (Dave) at Ford Bronco Zone Forums
or
The Pump relay probably has the points welded. by Seabronc
a bad fuel pump relay or EEC Power Relay hanging closed; If the EEC Power Relay goes bad, it could be sending the signal to the fuel pump relay to turn the fuel pumps on; One easy test for this is: Without the key in ignition, bump the starter over @ the starter relay using a screwdriver. If it is the EEC Power Relay, the truck will start without the key in the ignition..." MIESK5 NOTE; from Ford EVTM; The Control Module (PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay or the integrated relay control module. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.
The actuator/switch needs to be adjusted
When the ignition is switched to the ON position, it turns the EEC Power Relay on. The EEC Power Relay provides power to the EEC-IV processor and the control side of the fuel pump relay. Power for the fuel pump is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flow is through the fuel pump relay and Inertia Fuel Shutoff (IFS) switch to the fuel pump.
Switch Pin-Out Diagram & Continuity Testing (Logic Tables in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM) Source: by Broncobill78 (Dave) at Ford Bronco Zone Forums
or
The Pump relay probably has the points welded. by Seabronc
a bad fuel pump relay or EEC Power Relay hanging closed; If the EEC Power Relay goes bad, it could be sending the signal to the fuel pump relay to turn the fuel pumps on; One easy test for this is: Without the key in ignition, bump the starter over @ the starter relay using a screwdriver. If it is the EEC Power Relay, the truck will start without the key in the ignition..." MIESK5 NOTE; from Ford EVTM; The Control Module (PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay or the integrated relay control module. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.
BroncoJoe19
Active member
If your fuel pump is always on, the Fuel pump relay is stuck ON, or it is being continuously triggered to stay ON.
How to check a relay
http://www.fordforumsonline.com/forum/electrical-lighting/144-howto-check-relay.html
The fuel pump relay is triggered by grounding circuit 97 which is a T/LG wire.
That wire runs from the EEC (the engine computer) through the self test connector, and then on to the trigger side of the fuel pump relay.
Look to this picture and locate the fuel pump test pin.
If that port is shorted to ground the pumps will stay on.
Try disconnecting the EEC, and then check to see if that port has continuity to ground. IF it does, then you have to locate the short to ground in that wire/circuit.
IF NOT... then the EEC is bad and is shorting to ground.
This is assuming that you already checked and ruled out a bad relay as the culprit.
How to check a relay
http://www.fordforumsonline.com/forum/electrical-lighting/144-howto-check-relay.html
The fuel pump relay is triggered by grounding circuit 97 which is a T/LG wire.
That wire runs from the EEC (the engine computer) through the self test connector, and then on to the trigger side of the fuel pump relay.
Look to this picture and locate the fuel pump test pin.
If that port is shorted to ground the pumps will stay on.
Try disconnecting the EEC, and then check to see if that port has continuity to ground. IF it does, then you have to locate the short to ground in that wire/circuit.
IF NOT... then the EEC is bad and is shorting to ground.
This is assuming that you already checked and ruled out a bad relay as the culprit.
BroncoJoe19
Active member
Did you remove the ignition switch?
Ahhhh... the wonders of trouble-shooting. Removed the starter switch, tested relays, checked for grounds and shorts...... got frustrated with it all, put everything back together, (still not sure where a couple of nuts go), and wonder of all wonders, everything is working properly now...... sigh... oh well, I may not know what I did, but what ever it was, it worked... Thanks for advice/info/ideas fella's.
BroncoJoe19
Active member
LOL... well good for you! I hope it stays working for you. 
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Seabronc
New member
Must have been those two nuts :lol:
