Cranky “Moose” 2.9l

[Briguy]

Got a bush find a 1987 ford ranger 4x4 STX club cab me and wife have already named “Moose”. Having trouble getting it going but I know it wants to run.

First problem fuel pump relay. I have experience with my other 1987 ranger and the first thing I noticed was the ground wire for the relays was off the negative terminal of the battery. However the former owner tore everything apart trying to find the problem and didn’t put everything back.

After reconnecting the ground, inertia switch, taping a bunch of connections and bare wires I still didn’t hear the fuel pump. On a whim and because I did everything else, including the test port fuel pump check, I had a spare computer kicking around from my other ranger which I installed. I then heard the fuel pump turn on and had pressure in the rail. Yeehaw. It started but I heard lots of hissing vacuum lines and it ran real rough so I fixed some vacuum lines, threw some new gas in, I also changed the spark plugs because they looked real old and I had a spare set. I noticed the plugs were very wet.

It started better after doing this then chugged then died. Then back to running rough and barely starting. So I did some digging around and found a faulty fuel regulator. (Gas was pumping through the vacuum line on the back into the intake manifold port) so I switched it out, however I misread my Haynes manual and was reading the 2.4l and thought I had to remove the fuel rail and therefore the intake manifold in order to replace the fuel regulator which actually in the 2.9 has two bolts then pops out. So before I found that out I already had all the wires from the manifold off and vacuum lines and throttle cable and power steering cable off.

I tried starting it before I had all the wires reconnected accidentally. And it sputtered then popped then died. (Im thinking it burned the excess fuel the was sucked/pumped into the intake) Then connected them all and now it cranks and cranks but no start and no sound from the fuel pump relay. Tried the ground test on the test connector and not a click. Did I inadvertently mess up the new computer or is there a wire I’m missing?

 

[franklin2]

The grounding test for the pump on the test port connector has nothing to do with the computer. The computer grounds that same wire you are grounding on the test port to fire the fuel pump relay. If your ground wire on the test port does not fire the fuel pump relay and make the fuel pump run, then the computer is not going to fire the relay and fuel pump either.

Make sure you have 12v at the fuel pump relay. One wire will have 12v at all times, even with the key off. The certain diagram I am looking at says this is a black/yellow wire. This is the wire that feeds the fuel pump when the relay clicks.

There is another hot wire, it is red. It is hot only with the key in run and comes from the EEC relay. This red wire goes to the coil of the fuel pump relay. But the relay will not click with the red wire being hot, because there is no ground for the coil. The ground for the coil is the lightblue/orange wire. This should be the same wire that goes to the test connector. The computer grounds this wire(or you do with a jumper in the test connector) and this gives a ground to the fuel relay coil and makes the relay click when the red wire is hot.

When the relay clicks, and you have power on the relay, it should send power out to the pump on the darkgreen/yellow wire which feeds the inertia switch and then goes to the fuel pump.

 

[Briguy]

Tested red wire and there is 0.01 v when key is on

 

[Briguy]

The grounding test for the pump on the test port connector has nothing to do with the computer. The computer grounds that same wire you are grounding on the test port to fire the fuel pump relay. If your ground wire on the test port does not fire the fuel pump relay and make the fuel pump run, then the computer is not going to fire the relay and fuel pump either.

Make sure you have 12v at the fuel pump relay. One wire will have 12v at all times, even with the key off. The certain diagram I am looking at says this is a black/yellow wire. This is the wire that feeds the fuel pump when the relay clicks.

There is another hot wire, it is red. It is hot only with the key in run and comes from the EEC relay. This red wire goes to the coil of the fuel pump relay. But the relay will not click with the red wire being hot, because there is no ground for the coil. The ground for the coil is the lightblue/orange wire. This should be the same wire that goes to the test connector. The computer grounds this wire(or you do with a jumper in the test connector) and this gives a ground to the fuel relay coil and makes the relay click when the red wire is hot.

When the relay clicks, and you have power on the relay, it should send power out to the pump on the darkgreen/yellow wire which feeds the inertia switch and then goes to the fuel pump.

I thought the eec relay is turned on with the ignition then it runs through the computer then through the fuel pump relay ABS the computer work like a timer telling the pump to only fire for 2 seconds and not run again until a certain rpm is reached.

 

[bobbywalter]

I thought the eec relay is turned on with the ignition then it runs through the computer then through the fuel pump relay ABS the computer work like a timer telling the pump to only fire for 2 seconds and not run again until a certain rpm is reached.

grounding test can be done with ecm disconnected on obd1 due to the ignition lighting the relay power.

 

[franklin2]

Tested red wire and there is 0.01 v when key is on

That's no good. The red wire is the main 12v from the EECIV relay and powers the ECM, injectors, and some output devices from the ECM.

 

[Briguy]

That's no good. The red wire is the main 12v from the EECIV relay and powers the ECM, injectors, and some output devices from the ECM.

Does it only run for a couple seconds or all the time when key is on?

 

[gaz]

@Briguy
With the key on, the fuel pump will only run for a couple seconds unless the PCM realises 500 engine RPM (that the engine started and is running, then the pump stays on).

 

[Briguy]

@Briguy
With the key on, the fuel pump will only run for a couple seconds unless the PCM realises 500 engine RPM (that the engine started and is running, then the pump stays on).

So the red wire will only have power for two seconds or is it a different wire that energizes the relay and flips the switch

 

[franklin2]

The red wire will be hot any time the key is in run. The computer grounds the other side of the coil for a few seconds which energizes the relay. If you do not have power on the red wire, it will not work.

 

[Briguy]

The red wire will be hot any time the key is in run. The computer grounds the other side of the coil for a few seconds which energizes the relay. If you do not have power on the red wire, it will not work.

According to the wiring diagram the red wire joins up with a bunch of wires and then originates from the computer is that correct?

 

[franklin2]

The red wire originates from the EEC relay. The EEC relay is activated by the keyswitch. Then the EEC relay makes the red wire hot when the key is on, and the red wire distributes power to all those different places, including the fuel pump relay coil. The EEC power relay is sending 12v to the computer, not the computer sending power the other way.

The computer grounds the LB/O wire when it wants to activate the fuel pump relay. But if there is not 12v on the red wire, the fuel pump relay will never activate, even if the computer grounds the LB/O wire.

 

[Briguy]

The red wire will be hot any time the key is in run. The computer grounds the other side of the coil for a few seconds which energizes the relay. If you do not have power on the red wire, it will not work.

The red wire originates from the EEC relay. The EEC relay is activated by the keyswitch. Then the EEC relay makes the red wire hot when the key is on, and the red wire distributes power to all those different places, including the fuel pump relay coil. The EEC power relay is sending 12v to the computer, not the computer sending power the other way.

The computer grounds the LB/O wire when it wants to activate the fuel pump relay. But if there is not 12v on the red wire, the fuel pump relay will never activate, even if the computer grounds the LB/O wire.

i can hear the eec relay click when the ignition is on.

The red wire originates from the EEC relay. The EEC relay is activated by the keyswitch. Then the EEC relay makes the red wire hot when the key is on, and the red wire distributes power to all those different places, including the fuel pump relay coil. The EEC power relay is sending 12v to the computer, not the computer sending power the other way.

The computer grounds the LB/O wire when it wants to activate the fuel pump relay. But if there is not 12v on the red wire, the fuel pump relay will never activate, even if the computer grounds the LB/O wire.

Alrighty solved two problems with that information. First off the eec relay was missing a red wire I found out it was inserted in the fuel pump relay in a blank spot then turned the key on and still no power to the red wire did some testing and found that even though it was clicking it wasn’t supplying power to the red wire. Replaced with new relay and I now have power to the red wire on fuel pump relay. Fuel pump relay still doesn’t click however

 

[Briguy]

The red wire originates from the EEC relay. The EEC relay is activated by the keyswitch. Then the EEC relay makes the red wire hot when the key is on, and the red wire distributes power to all those different places, including the fuel pump relay coil. The EEC power relay is sending 12v to the computer, not the computer sending power the other way.

The computer grounds the LB/O wire when it wants to activate the fuel pump relay. But if there is not 12v on the red wire, the fuel pump relay will never activate, even if the computer grounds the LB/O wire.

Hooked a test light on the + terminal to the LB/O wire and turned the key on and the light did not shine for any period of time

 

[franklin2]

Hooked a test light on the + terminal to the LB/O wire and turned the key on and the light did not shine for any period of time

Hmm, computer is not grounding the LB/O to cycle the fuel pump relay. BUT, you should now be able to ground the test port terminal for the fuel pump relay, and the fuel pump relay should click and the fuel pump should run. That will test everything except the computer. The fuel pump relay and it's wiring, the wiring to the fuel pump/inertia switch, and the fuel pump itself.

Make sure you turn the key to run when doing the test port grounding test.