New engine - but is it getting fuel?

[Gary Lewis]

If so, then one of two possibilities, bad connection, or pump is stuck from sitting. If Ford used the same pump in 1986-89 then try bypassing the resistance wire and see if will run then.

Interesting information. My fuel gauge is reading as full, but I know there;s only about 3/4 of a tank. It is possible the pump is stuck from sitting.

I do not know how to bypass the resistance wire. I'll look in my manual to see which wire that is, but how do I bypass it.

Bill - I'm quite sure that AllData is wrong. See below - it is a 1.000 ohm resistor and only used in the Bronco - according the a 1986 EVTM I acquired from a friend of mine.

Steve - It is now time to check the fuel pump relay to see if it is getting power. The easy thing to do is to put your hand on it and turn the key to Start - if your arms are long enough or if you have a helper. If not, put your meter on the red wire of the relay and it should have 12v. Put your meter on the t/lg wire and it should have 12v until you turn the key to Start and then it should go to about 1 volt.

[NotEnoughTrucks]

If you pull the little red/light blue wire off the starter solenoid/relay you should be able to turn the key to Start w/o spinning the engine. And while the key is in Start you should have power to both pumps. If not you need to see if the relay is being pulled in, but let's try this first.

IHi Gary - Thanks for getting back to me.

I did as you suggested. Connecting to the pink/bl h wire at the in-tank fuel pump with the red/blue wire disconnected at the starter solenoid and with the key in Start position I got 0 volts.

Steve, did your truck originally have dual tanks? I think I understand you are only running single tank now.

If so, is the correct tank selected? If you don't have a tank select switch, there is a jumper plug that is supposed to replace the switch.

If your inline pump is running and from the sounds of your description, it is running correctly, the in tank pump receives the voltage from exactly the same point on C120.

Bill, that resistor wire has a note in the diagram in the EVTM that says Bronco only. No idea why this is. (Gary beat me to it!)

I think your fuel pump relay is controlled correctly. With the engine not running, it will pick for a second, then release to shut off the fuel pumps. There is a handy point on the EECIV test connector for the fuel pump. Essentially, it is the ground side of the relay, same as the output from the computer. The fuel pump relay receives power from the EEC power relay when the key is on, the computer completes the circuit to ground. Grounding the test point allows you to troubleshoot the fuel pump wiring without the engine running.

[sgauvry]

If not, put your meter on the red wire of the relay and it should have 12v. Put your meter on the t/lg wire and it should have 12v until you turn the key to Start and then it should go to about 1 volt.

Gary - In the first test measuring volts on the red wire, I had 12 v.

On the second test with my meter on the tan/gr d wire, I had 26 volts and when trying to start it dropped to 0 volts.

 

[Gary Lewis]

If not, put your meter on the red wire of the relay and it should have 12v. Put your meter on the t/lg wire and it should have 12v until you turn the key to Start and then it should go to about 1 volt.

Gary - In the first test measuring volts on the red wire, I had 12 v.

On the second test with my meter on the tan/gr d wire, I had 26 volts and when trying to start it dropped to 0 volts.

Disregard the 26v as that has to have been an EMF spike. So the computer is closing the relay. Now test the p/bk wire out of the relay. It should go to 12v in Start.

If it does and the pumps don't run check the inertia switch just above the passenger's feet. It may be tripped.

[Gary Lewis]

Steve, did your truck originally have dual tanks? I think I understand you are only running single tank now.

If so, is the correct tank selected? If you don't have a tank select switch, there is a jumper plug that is supposed to replace the switch.

If your inline pump is running and from the sounds of your description, it is running correctly, the in tank pump receives the voltage from exactly the same point on C120.

Bill, that resistor wire has a note in the diagram in the EVTM that says Bronco only. No idea why this is. (Gary beat me to it!)

I think your fuel pump relay is controlled correctly. With the engine not running, it will pick for a second, then release to shut off the fuel pumps. There is a handy point on the EECIV test connector for the fuel pump. Essentially, it is the ground side of the relay, same as the output from the computer. The fuel pump relay receives power from the EEC power relay when the key is on, the computer completes the circuit to ground. Grounding the test point allows you to troubleshoot the fuel pump wiring without the engine running.

That's a good tip, Ray:

I think your fuel pump relay is controlled correctly. With the engine not running, it will pick for a second, then release to shut off the fuel pumps. There is a handy point on the EECIV test connector for the fuel pump. Essentially, it is the ground side of the relay, same as the output from the computer. The fuel pump relay receives power from the EEC power relay when the key is on, the computer completes the circuit to ground. Grounding the test point allows you to troubleshoot the fuel pump wiring without the engine running.

[sgauvry]

Now test the p/bk wire out of the relay. It should go to 12v in Start.

If it does and the pumps don't run check the inertia switch just above the passenger's feet. It may be tripped.

The pink/black H wire tested OUT of the relay went to 12v. The HP pump continues to engage as I can hear it, but the in-tank fuel pump makes no sound and is not putting forth any fuel. It still measure at 0 volts with red/blue start wire detached/attached from the solenoid.

Not sure how to engage the inertia switch. I jiggled the trigger at the top of it and depressed it a few times. Never felt it engage, but my oil light now comes on. It wasn't coming on before.

 

[Gary Lewis]

Now test the p/bk wire out of the relay. It should go to 12v in Start.

If it does and the pumps don't run check the inertia switch just above the passenger's feet. It may be tripped.

The pink/black H wire tested OUT of the relay went to 12v. The HP pump continues to engage as I can hear it, but the in-tank fuel pump makes no sound and is not putting forth any fuel. It still measure at 0 volts with red/blue start wire detached/attached from the solenoid.

Not sure how to engage the inertia switch. I jiggled the trigger at the top of it and depressed it a few times. Never felt it engage, but my oil light now comes on. It wasn't coming on before.

The inertia switch is before the high pressure, in-line pump. So if you are getting that pump to come on then you have power back that far. And, as has been said, since both pumps run off the same circuit then you have a wiring issue between the high pressure and the in-tank pump.

[85lebaront2]

Bill - I'm quite sure that AllData is wrong. See below - it is a 1.000 ohm resistor and only used in the Bronco - according the a 1986 EVTM I acquired from a friend of mine.

Steve - It is now time to check the fuel pump relay to see if it is getting power. The easy thing to do is to put your hand on it and turn the key to Start - if your arms are long enough or if you have a helper. If not, put your meter on the red wire of the relay and it should have 12v. Put your meter on the t/lg wire and it should have 12v until you turn the key to Start and then it should go to about 1 volt.

Yes, 1986 says Bronco only, 1985 shows it and looks just like the 1985 EVTM pages you shared.

[sgauvry]

Steve, did your truck originally have dual tanks? I think I understand you are only running single tank now.

If so, is the correct tank selected? If you don't have a tank select switch, there is a jumper plug that is supposed to replace the switch.

If your inline pump is running and from the sounds of your description, it is running correctly, the in tank pump receives the voltage from exactly the same point on C120.

Bill, that resistor wire has a note in the diagram in the EVTM that says Bronco only. No idea why this is. (Gary beat me to it!)

I think your fuel pump relay is controlled correctly. With the engine not running, it will pick for a second, then release to shut off the fuel pumps. There is a handy point on the EECIV test connector for the fuel pump. Essentially, it is the ground side of the relay, same as the output from the computer. The fuel pump relay receives power from the EEC power relay when the key is on, the computer completes the circuit to ground. Grounding the test point allows you to troubleshoot the fuel pump wiring without the engine running.

Thanks Ray. Not certain about dual tanks. I bought it with only one in 2009. I have not seen a tank selector switch on it either.

I know when I've plugged my diagnostic tester into the test plug I can hear the pumps working. Maybe I'll do that just to see what happens.

[NotEnoughTrucks]

Thanks Ray. Not certain about dual tanks. I bought it with only one in 2009. I have not seen a tank selector switch on it either.

I know when I've plugged my diagnostic tester into the test plug I can hear the pumps working. Maybe I'll do that just to see what happens.

Try as I might, I could not find an accurate reference to the connector for the tank switch, but it exists in all trucks.

On the dual tank trucks, there is a switch in with the heater controls, on single tank trucks, the switch is omitted, but the connector still exists near the heater control. There is a description of the 6 pin plug in the top corner of p.104 in the EVTM, but no references to connector number.

The plug that replaces the switch has two jumpers on it. There are two rows of 3 pins. The middle position will be jumpered to either the front or rear tank wiring. If the plug is missing, your in tank pump will not run and the fuel gauge will read empty. This is also a handy place to check for voltage to your in tank pump although it would not rule out a problem between the plug and the tank itself.

I also have had trouble with the fuel tank connectors. The connector body locking ears typically break off, resulting in an intermittent connection to the in tank pump and gauge sender. I sourced a replacement from Napa, but they are getting a little harder to find these days.