1987 Ranger Super cab Fuel Pump Problem

[txrangr1988]

Ok so I have been trying to fix this problem for a while now and have pretty much exhausted the search button on this sight lol.

So here is the problem/problems:

When I turn the key to the on/engine off position the fuel pumps do not cut on. My truck has the 2 tank option so it has 3 pumps. I replaced the Fuel Pump Relay and that didnt fix it. I then went ahead and replaced the EEC Relay as well still no priming or anything from the pumps when I turn the key on.

I ran a test where it tells you to jump the Yellow wire(12v constant) to the orange with light blue tracer (fuel pump signal) and it kicked the pumps on. I even had it to where when they were running switched to the rear tank and it swapped over and that pump turned on as well.

When I test the fuel pump relay I have the 12v constant with the yellow wire, 12v on the red wire when I turn key on engine off. So I am thinking it has to deal with the relay not finding a ground through the Tan with light green tracer wire that goes to pin 22 on the PCM.

I pulled the codes with a test light and what I got was:

Code: 63 Throttle Position (TP) circuit fault, below minimum voltage
Code: 34 ?????????
Code: 67 Neutral Pressure Switch (NPS) circuit failure, circuit open
Code: 87 Primary Fuel Pump Circuit Failure

The other problem that I am having that makes me think the PCM is bad is due to the fact when I turn the key on none of my pre check lights come on except the seat belt light.

Any help would be greatly appreciated.

Thanks
Dustin

P.S.:The truck spins over but will only run when you spray either into the throttle body.

 

[txrangr1988]

oh and just to add the truck is a 1987 super cab with two tanks 4x4 with manual locking hubs and a 5spd manual

 

[librum]

See PM, but I doubt it will help due to year difference.

The code 34:
EGR control circuit fault (ex. v8 models) and/or
EVAP control system fault/voltage higher than closed limit (v8 models).

Signal grounds seems to be the issue.

That code also tells me that you are a V8. If it were a V6, I would be advising you to check the wiring in the two combo electrical connectors on the rail on the riders side of the engine for heat damage to wiring.

 

[txrangr1988]

Would those be through the PCM or as the book calls it a ECM

 

[librum]

Different names for the same thing. The 'main computer'.

Are you a V6 2.9? My cribsheet says you are throwing V8 codes. Was the ECM replaced?

 

[txrangr1988]

Not to my knowledge. The truck is a 2.9 V6. I have had this truck in the family since 1987 and only me and my grandfather have worked on the truck.

 

[adsm08]

Well, there is one good way check for bad ground through the tan wire. Stick another wire up there and ground it. See if it makes the pumps run. That wire does ground through the PCM though, so a bad computer could well be at fault.

 

[librum]

Txrangr88, Adsm80 is correct, a bad computer can cause your issues, but I would advise you try everything else first. Oh, when I said 'signal ground' I also meant 'signal return'. Look at the wiring diagrams.

I have a spare computer. I did not need it. If you get to the point of no-other-choice, make sure you search on the specific part number on yours. Yours will probably be hard to find. Also, you can make a 'break-out' box, by gutting one, and putting in euro barrier strips. You want the euro style so you have the 'tube' to hold test leads.

Let us know how you come along.

Librum

 

[txrangr1988]

Hey guys what all ways can I test this Computer? I have shot power to the computer with the ignition on and actually used the ground that the computer uses which is an orange water. I have been using this website for my wiring diagram: http://www.justanswer.com/ford/0slw7-concerning-1987-ford-ranger-2-9l-engine-w-dual-fuel.html

Thanks all for the help. My part number on my ECU is:E7TF-12A650-BE1A

 

[adsm08]

The best way to do this is to check ground for the relay gate while cranking. If none, check continuity of the wire to the PCM, if good, replace computer.

The thing about modules is that there isn't really any way to test them directly. You kinda have to test everything else around them and then assume the module is bad when everything else comes up good.

 

[txrangr1988]

well I did find the actual case of the female portion of the relay cracked. I made sure that it was getting a good connection the relay (which it was) and still nothing. Going out there tonight after work and check continuity of the wire itself. UGH THIS WIRING CRAP IS FOR THE BIRDS!!!

 

[txrangr1988]

Hey so update is that the truck is still broke. I am going to order a ECM I guess. Where is the ground for the EEC relay located? I keep reading that it is on the fender but cant seem to find it. Also where is the 30a fuse link? What wire does it run off of?

 

[bobbywalter]

did you jump the pin on the eec test connector?

ground that first. if the pump runs the pcm may be shit.

i ASS-U-ME that you bridged or tested the rollover switch???


there is a ground at the battery...the smaller wires. make sure it has continuity to the pcm case ground and the battery.

i often see those pulled apart or spliced onto a cheap aftermarket replacement battery terminal and slipped out causing this type of issue.

 

[txrangr1988]

did you jump the pin on the eec test connector?

ground that first. if the pump runs the pcm may be shit.

i ASS-U-ME that you bridged or tested the rollover switch???


there is a ground at the battery...the smaller wires. make sure it has continuity to the pcm case ground and the battery.

i often see those pulled apart or spliced onto a cheap aftermarket replacement battery terminal and slipped out causing this type of issue.

What do you mean rollover switch? If youre referring to the inertia switch I have ohm'd it out and it is good. I jumped the actual wires that would energize if the fuel pump relay received its ground from the PCM.

What wires should I jump on the EEC relay? I'm going to order a EVTM this week.

Thanks for the help guys.

 

[bobbywalter]

does it turn on when you ground the eec connector?


the small ground wires at the battery post are good and ohm out too?