Ok folks my 1988 Bronco II has me stumped. She will not start and there is no fuel pump sound. I can make the pump work by hot wiring it but she still will not start.

The wiring shows that there is a place (unknown) that has 8 red wires meeting. I don't know where that is but, are the red wires hot with the key on?

When I run a system check I get a 96 or fuel system error.

I have been working on this for more days than I care, to so please help.

The problem started when I went to tape a bare spot on the yellow wires going to the EEC power relay. The PO had really done some bad fixes and lots of bad wire spots. I know better, but I did not remove the - terminal battery and a spark jumped.

I have switched the relays, switched the EEC still no good. All of the fuseable links check ok (the ones I can find)

HELP

 

I suspect that bunch of red wires are the EEC power wires that feed 12 V power to the ECA, and various EEC-IV sensors/solenoids. They should be hot with the key on.
One of the leads in the self-test connector grounds the fuel pump relay with the key on. Does this make the pump run?
I assume that you have power to the EEC relay because you can run the self-tests.
Do you have power to the fuel pump relay?
Do you have power to the inertia switch?
Is the inertia switch tripped?
Do you have power at the pump?
Is the ground good?

 

On the fuel pump relay the yellow wire is hot all the time, the red is cold even with the switch on. The tan green and the orange blue are cold always. The inertia switch is cold with key on. I checked the switch it is not tripped. I have no power to either pump, but if I hot wire the pump relay the pumps come on but the car will not start. I think that some how the red wires are not beig energized, but I have no clue where the junction of all 7 wires can be. Thank you for the fast answer.

 

Need to put the same information in both threads, or, I guess I should just stop responding in the thread in the 2.9 etc. forum, since there is more information here.
If the red wire is cold at the fuel pump relay, this is a problem. Is the red wire coming out of the EEC relay cold, too?

 

I am sorry about the double post I am new here. None of the red wires are hot with the key on or off. With the key on I have power to the gray yellow wire on both sides of the fuse link. Should all wires coming from the key switch be hot with the key on? I don't know if thay are I ran out of daylight. None of the red wires at any of the relays are hot with key on.

 

If the red wire at the EEC relay is cold, then not only is the fuel pump not getting power, the computer, the fuel injectors, nor any of the EEC-IV components are getting power. Haven't got time right now to look it up, but check your wiring diagram for the wires that feed the EEC relay, see which ones should be hot, and then see which ones actually are hot.

 

I talked with a friend that works at the Ford garage, he said the red is not hot with key on only in the run mode. He also told me that the green lt/tan wire on the fuel pump relay will be hot with key on, it is. I tried jumping the inertia switch, still no good. Since this is my daily driver I am getting desperate, but I am a 100% disabled vet with very few funds to spend on the garage way of doing things. Oh me what to do?

Thanks again mrshorty I sure appreciate your help.

 

Not sure where your friend is coming from -- maybe thinking of a different application? I just spent some time with mine (figuring out how someone before me had hard wired the pump in and returned it to it's proper state. Ended up buying a fuel pump relay to fix mine as it should be). Red lead of a voltmeter on that red wire at the EEC relay, black lead to the negative battery post should show 12 V with key on.
I just figured out what your friend was thinking. What he's thinking is red is actually the org/lt blue wire (may be a different color on your 88) that feeds power through the inertia switch to the fuel pump. He's right, that wire will be cold except when the control side of the relay is grounded (tan/ltgreen wire is grounded).
I'm going to describe the pertinent circuits. If you don't have a wiring diagram, it's going to end up sounding like a lot of mumbo jumbo. Make sure you have your wiring diagram handy.
To start, A relay is composed of two circuits: One I'll call the control circuit and another that I'll call the main circuit.
The yellow wire comes straight off the battery. It feeds power to the main circuit sides of both the EEC relay and the fuel pump relay, so it should be hot at all times. The main circuit on both of these relays is normally open.
When the key is turned on, the red/ltgrn wire feeding the control side of the EEC relay is powered, current flows through the control side of the EEC relay to the blk/ltgrn wire. This current flow causes the main circuit of the EEC relay to close, which feeds power to the red wire. amongst other, this red wire feeds power to the control side of the fuel pump relay, through the relay, then out to the tan/ltgrn wire which gose to the computer and the self-test connector. When the computer grounds this circuit, or you ground this circuit at the self-test connector, current flows through the control side of the circuit, which closes the main circuit (connects the yellow wire to the org/ltblu wire). Current can then flow to the inertia switch and on to the fuel pump.
To date, you've said that the red wire feeding the fuel pump relay is cold. I assume that means that you put probe it with the positive lead of a voltmeter/test light, negative lead to the negative battery post or other ground spot, and it shows 0 volts. This same red wire at the EEC relay is also cold. That tells me that either a) the EEC relay isn't closing or b) the yellow wire at the EEC relay is cold.

 

Thank you I will go out and check it right now and get back to you. This is a great site the owner(s) should be proud. In my other post I spoke of my 1980 British sports car(Triumph TR8) and of the electrical nightmare it had been, I love that car. I still come to the same spot I HATE electrical problems.

 

Thank you.
She is fixed. I followed your post and found that I had two bad relays. Who would think? Put in a new fuel pump relay and off she went.

Thank you again.