1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

[Gary Lewis]

The only use of that computer I can find in the master parts catalog is as shown below.  So, do you have the AOD transmission?  You'd have an "O" on the shift indicator with a "D" in the middle of it for Overdrive if you do.

If so, then this should be your parts list.  And, if so, then the O2 sensor should be E63Z 9F472-A.  I don't know if that is a 1-wire or a 2-wire.  However, I think it must be a 2-wire to take the orange wire.

Is it possible someone put the wrong O2 sensor in?

[axe2011]

It does have overdrive, I will have to do some more research on that sensor, I appreciate your help!

[axe2011]

I found this diagram on the Google box and it seems to suggest the orange wire is a ground. So maybe I will hook it to some ground and see if she runs a little less rich

[Gary Lewis]

Interesting.  It does show it as a ground.  And usually taking a solid state device to ground doesn't hurt things, so I think I'd ground orange and see what happens.

I imagine the intent was for orange to run all the way down to the O2 sensor, but just grounding it anywhere for a test might prove something.  Good luck!

[axe2011]

Sounds better with the orange wire grounded, I connected it with the other ground near the back of the drivers side valve cover.

More good news, I noticed the cruise wasn’t working and figured that was a later project. Then today I checked the fuse box and realized there was no fuse in the horn fuse slot…stuck one in and now I have a horn and cruise! Very happy!

[Gary Lewis]

Excellent!  You are making good progress.  

[axe2011]

Well since grounding the 02 sensor and timing the distributor and chasing down some vacuum leaks I have the truck running pretty smooth at idle.
I am still having issues intermittently where the fuel pump runs for a bit and sounds like it is draining into the rear tank and then it will stop and pressurize the rail. I am thinking it may be a fuel pump issue in the tank.
  When driving it runs smooth until you give it some mustard and then it cuts out. I thought maybe it was the coil, but a new coil didn’t help.  I’m thinking maybe that fuel pump issue is not pushing enough gas to the injectors under load. Anyone have this issue before or any suggestions?

[Gary Lewis]

Glad it is now running smoothly at idle.  But on the cutting out, can you describe it more thoroughly?  Does it bog and then come back?  Does it bog and stay bogged until the throttle is closed?

My thought, beyond fuel pressure, is the throttle position sensor.  I wonder if it is bad after a certain point?  I think the testing procedure is in Documentation/Electrical/ELECTRONIC ENGINE CONTROL (EEC) and then the EEC-IV and Diagnostics tabs.

[axe2011]

I can drive and get up to 50-55 smoothly if I gradually accelerate. Then around 60 or if I accelerate fast at pretty much any speed it kinda accelerates and cuts out really quickly which shakes the truck until I let off the gas.

I’ll try looking at he tps

[Gary Lewis]

I'm not really sure what a bad TPS would do while driving.  But if it told the computer that you'd dropped the throttle to idle then the computer would drop the amount of fuel it is injecting.  However, the throttle would still be open via the throttle cable, so the AFR would go really lean.  And that might mean the engine would either die or run very roughly.

[axe2011]

Got a good news update. I was trying to figure out what the issue was with the pump and noticed if I shook the wires in the harness it stopped running. So I started inspecting the wires and found that where a previous owner joined the wires the shrink wrap had very very small singular wires poking through and touching/grounding. I wrapped each wire where it was joined and the pump stopped clicking on and off randomly. I also noticed something over to the left of me in the engine bay also stopped clicking on and off.
I took the old girl out on a spin and was able to drive up to 70 with no issues. It even ran cooler and sounded great!

[grumpin]

That’s great! Good find!

[Gary Lewis]

Wow!  You've really come a long, long way on your truck in a short time.  I'm seriously impressed.  

[axe2011]

Couldn’t have gotten to where I’m at without everyone’s help and suggestions!