My dad's 92 ranger with a 4.0L wont start. With it at KOEO the fuel pump stays on until you turn the key off. It will only start if you spray some starting fluid in. After that it'll run like its got a huge cam. We've replaced the fuel pressure regulator, the rely, and changed the PCM. Nothing has worked. The only thing I can think of is it might be a chassis ground but I don't know where any are. Any info or ideas will be greatly appreciated.

 

Spark is working, because engine fires with starting fluid but recheck the Coil spark plug wires
should be
<<<<
1 2 3
5 6 4
<<<<

That could be the "cam issue", people check them then reverse the 5 6 4

Fuel Pump should only come on for 2 seconds when key is first turned on, it shouldn't come on again until engine is running.

Fuel pump relay is operated by the computer(PCM) by Grounding not 12v
When key is on fuel pump relay gets 12v but has no Ground so doesn't close, computer grounds it using a Light Blue/Orange wire to close it, for 2 seconds then removes the Ground to open it

The Light Blue/Orange wire goes to Pin 22 on PCM, this wire is also spliced to the VIP(OBD) connector.
This link has a drawing of the VIP connector with the fuel pump port labelled: Ford Ranger - Testing EEC-IV Equipped Engines

Make sure some one hasn't put a jumper in that port so fuel pump is on when key is.
And then check if the Light Blue/Orange wire is grounded/shorted

Your issue reads like bad gas or low fuel pressure, I would see if you can borrow or rent a fuel pressure gauge.
You should have 35psi after turn key on and off 3 times, assuming 2 second run time.

If not fuel pump assembly will need to be replaced.
Fuel pump running meaning it is getting power but not that it is pumping and you could have a hose disconnected in the assembly so fuel is just leaking out in the tank, not giving full pressure at the injectors.

 

I had same problem and found the in line fuel pressure regulator in gas tank was bad. You can't buy the regulator separate, you have to buy the fuel pump & sending unit assembly. I bought mine at O'Reillies for $223.00 after Ford said $900.00.

 

Thank you for the responses. I have checked the plug wires and they are correct, I haven't been able to check the fuel pressure yet though. Like i said It will start on starting fluid then run rough, then after about 15-20min it revs up and idles fine, but sometimes it only takes a few minutes. While it runs rough the check engine light is on, so I took it to the parts store to scan it but it cleared up before I got there, I scanned it and it didn't throw a code. If you start it and it "clears out" it will start fine for the rest of the day. It just doesn't make any sense to me. I think it could be a fuel feed problem but my dad said its fine because he doesn't want to pull the bed off. (Stubborn old man) Lol

 

Bump...still scratching my head trying to figure this truck out.

 

And what have you tried so far?

What does the fuel pressure show?
35psi??

Does the fuel pump shut off after 2 seconds, as it should, or is it still running with key on?

 

What doesn't make since is when it runs rough the fuel pressure is low I cant remember what it was I'll have to recheck it. Fuel pump keeps running with key on engine off. Never stops running.

 

Remove the Fuel Pump Relay and turn on key, see if fuel pump stays off
If it does then the Light Blue/orange stripe relay wire is Grounded which it shouldn't be.
This wire runs to 2 locations, pin 22 on the computer connector, and a slot in the OBD I VIP connector, it is on drivers side engine compartment.
Look here for what it looks like: Ford Ranger - Testing EEC-IV Equipped Engines

Drawing there show which slot is the Fuel Pump test slot.
Make sure no one has put a jumper wire there, if you Ground that slot fuel pump relay closes just like the computer would do when engine is running.
You can use that slot to test for ground on the light blue/orange wire
Key off
Disconnect battery's negative cable
Set OHM meter at lowest setting, put one probe in that above slot, place other probe on a good Ground.
0-1 ohms means blue wire is grounded, it should read high or N/C(no connection) if wire is as it should be, not grounded.
Disconnect computer, in case pin22 circuit is the issue
If ohms change to very high or N/C then computer circuit is the issue, new or not.
But I doubt it will change, if it does then check the pin22 blue wire on the connector and follow it as far as possible, short to ground could be near computer connector and when it was remove the ground was lifted.
Start tracing the blue wire(from VIP connector and fuel pump relay) and move wire around, see if you can find a place where ohms change, i.e. the bare spot where it is touching metal or a ground.

 

The fuel pressure regulator is in the tank, the item that people think is a fuel pressure regulator on the 4.0 is actually a fuel damper. I learned this when mine stated starting hard and then quit starting. You can't buy the regulator separate, you have to buy the whole fuel pump assembly.

 

Haven't done the wire test with volt meter yet but I did confirm that with the relay unplugged the fuel pump does not run with koeo.

 

GOOD NEWS!!!! I got back working on my dads ranger, apparently the PCM for a 92 4.0L 4x4 ranger is a single year thing which is why a 93 PCM did nothing. I was able to find one at the local junk yard for 50 bucks. plugged it in and boom problem solved. after testing it everything was great then while my dad was revving it up in park there was a bang and the truck took off. Now there is no park. Any ideas?

 

Common issue on all Ford trucks with column shift and automatics, there are a couple of screws under the dash that hold the shift cable in place they get loose and even fall out.

Google: Ford ranger loose column shifter

There are a few videos, usually an easy fix but a pain to get at.

 

The problem was a broken parking pawl. We orderd one from a place online but its been a week and I haven't heard anything from them. Anybody tried welding a broken parking pawl?