A couple of months ago my 1989 F150 (302, AOD) wouldn't start. It would turn over and had spark but wasn't getting fuel. I could hear that the fuel pump wasn't working so I replaced the filter, relay and pump but it made no difference. Still turned over and had spark but no fuel. I took it to the corner garage and they worked on it and the pump started working. They didn't fix anything - it simply started working while they had it. I drove it for a few days and it was fine. Then the same problem returned. Turned over, had spark, but the fuel pump wasn't working. I cleaned all the wiring harnesses and connections and the truck started and worked great for a couple of months. Last week I was driving and the truck died. Wouldn't even turn over. Battery was fully charged, etc. The headlights and power door locks worked but nothing else. I took it back to the corner garage. They tinkered and the truck got back to the point where it would turn over but there was no fuel. They didn't do anything to get it to turn over - that part of the problem seemed to fix itself. Again, they couldn't get the fuel pump to work. They spent a day working on it and gave up. They checked all fusable links and fuses and couldn't find any problems. They could get the truck to run by getting power to the fuel pump relay from a different source. I got the truck back from the shop but now it's back to the point where it won't even turn over again.

Does anyone have any suggestions or have experiences with the same problems?

 

Sounds like you have a ground or connector problem at your Neg. (-) post of your battery.
Make sure the small black ground wire with a green stripe is well grounded at the post and big ground wire has a good ground on the engine block.

 

You might have some trouble with the large yellow wires under you air cleaner box - Ford used "glue like junk" to hold 3 wires together under the air cleaner and they pretty much power everything. I had this joint go bad/corrosion on my 88 and it killed everything. Talked to an old tech at Ford, pointed me to that and I found my problem. Very common according to him.

 

The grounds look like they are making good contact. I also removed the air box to check the group of 3 wires that were mentioned in the previous post but there was no group of wires under the air box of my truck.

Any other thoughts or suggestions? I have a friend who thinks the ignition switch might be faulty because I can opperate accessories that don't run through the ignition but can't work accessories that only work when the ignition is in the "on" position. Does this sound likely?

 

An 89 has a different wiring harness.

 

My bad then, my last truck with this yellow wire issue was an 88 302/C6.

 

Your friend may be right about the ignition switch but it may also be that the ignition switch and the plug that plugs into it is bad also. Check the large yellow wire(s) at the plug and see if they are hot with a test light.
If they are not hot (in the no start condition) then look under the hood as described below.

I would also look at the fuse links that hook to the battery side of the starter solenoid, they may be burnt inside and just touching. Try to pull them apart and if they stretch they are bad.

I am not sure on an 89 F series but it may also have a load split and two plugs coming off the wire (#10 GA Black with Orange stripe) going from the A/C Generator to the starter solenoid. One of these plugs has a wire that goes to the Ignition Switch (Yellow wire) and there is a fuse link in this wire. Do the same pull thing on this fuse link as the ones above.

 

The yellow wires he speaks of above are the same ones I mentioned. I too thought I had a bad ignition switch - it wasn't - it was the yellow wires that were the problem. Do as he say's, check for power at the ign switch at the yellow wires and see what you find.

 

I checked for power at the two yellow wires on the connector and they were both getting about 11 volts. I replaced the ignition switch and now the truck turns over but doesn't start. I checked all fuse links I could find and they were all good. Any ideas why the fuel pump is not getting power?

 

The fuel pump relay on the left inner fender might be bad, they are known to fail.