Fuel Problems 4.0

[OneGoofyGuy]

My 1989 Ford Ranger 4.0 needed a new fuel pump and while I was down there I replaced the fuel filter. The only time that it will start is if I remove the air duct and I spray gas into the throttle body. I've checked the pressure and it ran about 35-40 psi which is normal? This motor came from a crate, it was bought, put in the truck and just sat there for a bit under a nut tree. It's got enough fuel coming in but it won't start. Any ideas?

 

[Dirtman]

Are the injectors getting power?

"Sat for a bit under a nut tree" = rodents have eaten through your wiring.

 

[bobbywalter]

...did you hook up the crank trigger?

 

[OneGoofyGuy]

...did you hook up the crank trigger?

It cranks over. The only time it while run is if I spray gas into the throttle body.

 

[OneGoofyGuy]

Are the injectors getting power?

"Sat for a bit under a nut tree" = rodents have eaten through your wiring.

All injectors are powered

 

[Dirtman]

Doesn't the crank sensor control spark not the injectors?

 

[bobbywalter]

The crankshaft position sensor.

This helps dictate injection firing events in relation to valve events. It is by the balancer

 

[bobbywalter]

Spout and saw and idm missing from eec input ect

 

[OneGoofyGuy]

If the sensor wasn't working it wouldn't fire at all right?

 

[bobbywalter]

No and yes.

I think it's working. But start there and work back to pcm and then back to engine. The outputs from the module may not be making it to pcm....or 58 and 59 may not be on inj harness.

 

[RonD]

Yes, but the crank sensor is connected to the EDIS-6 spark module, which is working since 50/50 test gets engine to start.

The EDIS-6 module sends this crank sensor pulse(PIP) to the engine computer(PCM), and PCM then opens fuel injectors based on this Timing pulse from the EDIS-6 module

Simple test to see if PCM is getting PIP signal is the CEL(check engine light) and/or Tachometer
When you crank the engine CEL should go off(assume CEL was on with key on, lol), than means PCM is seeing PIP
Tach should also go up a bit, 200rpm, when cranking but thats from EDIS-6 but shows it is outputting a PIP


I assume you are using a 1994 or earlier 4.0l PCM?
I would unplug connector on EDIS-6 module and 60-pin connector on PCM and inspect for corrosion or any pin/connector damage
Then plug both back in and try to start, unplugging and plugging back in connectors often cleans off the pins so they can reconnect, especially if they have been sitting awhile




If you don't have a CEL but do have a 12v test light then you can make one pretty easily in the engine bay
1994 and earlier use OBD1 and will have a test port on the PCMs wiring harness in engine bay

Looks like this: https://www.therangerstation.com/tech_library/OBD_I.shtml

Self test OUT is the CEL, well the ground for the CEL bulb
So hook 12v test light to Battery Positive and to Self test OUT slot(do not hook up jumper as shown in drawing)
Turn on the key, test light should come on
If not then PCM is not powering up, no 12v with key on

If test light lights up, then crank engine, if test light goes off PCM is getting PIP signal, if it stays on then its NOT getting the PIP signal from EDIS-6

 

[bobbywalter]

In short. The ignition can potentially work without the ecm at a fixed rate as long as the crank profile is visible


Sounds like ecm is running fuel pump. Unless that is jumpered to key somehow


You would at least think the idm and pip are reporting...

Do you have a noid light? You could try to manually strobe the injectors and see if it runs...if you have a cell and it codes I would assume it's working


Otherwise making sure all of the grounds near the battery are on and the injector wires are good.

 

[OneGoofyGuy]

As of right now when I go to turn it over it will putt starter putt starter putt putt starter putt. It's firing and getting fuel I guess. But the thing is it's not "running" it's like it will get fuel and quit over and over
^ I know thats kinda hard to imagine. ^

 

[OneGoofyGuy]

*New update*

All it needed was 2 cans of starting fluid so can lubricate the upper valves and lifters because it had been sitting so long and cranks right over now.

 

[RonD]

Good stuff

But not sure what that means