Long time no talk. Well anyway let me get to the issue.

I have a 1990 Ford Ranger XLT 4X4 2.9L V6. I have a no start issue that comes and goes. When it is running there is no problems. I know it is a fuel issue. I have already replaced the fuel pump and fuel pressure regulator.

The problem is... you know how old Ford fuel injection systems work. You turn the key on, the fuel pump will prime the system, then you hear the solenoid click, turning off the fuel pump, and then you can start the engine. All that happens within a half of a second.

Well mine will keep trying to prime the system for another 2 minutes if not more before the solenoid clicks and the system is fully primed.

I replaced the fuel pump, fuel filters, and fuel pressure regulator. And there is no leaks. When the truck does start it runs just fine.

What else could be causing this?

And I would like to know how does the fuel system know it's at full pressure? How does the system know to turn off the fuel pump? There is no fuel pressure sensor. The pressure regulator is mechanical/ vacuum. What tells the fuel pump to shut off when it hits full pressure? I'm thinking whatever that is, that is the problem.

And yes I already did a thread search and did not find my problem. Found things close. But not exactly what my problem is.

 

There is no fuel pressure sensor on Rangers, in any year
So the priming of the system is a timer, 2 seconds only, in the computer
Each time key is turn from off to on fuel pump should run for 2 seconds and thats it, it won't run again until engine RPMs are above 400, cranking speed is 200
Or
You cycle key off and on again

All Fuel injected Rangers 1986 to 2011 had this same 2 second timer with key on, computer boot up

So what you describe is a computer issue
Pull out the computer and have a look at the circuit board, there are 2 or 3 barrel type capacitors, they leak after 20 years, and that will cause what you decribe
They should be replaced regardless, while computer is out, not hard to do

So that would be my first stop

Picture of circuit board here: Ford EEC-IV
Its the 3 blue capacitors in this pic, but they can be black and in different locations, at least 2 but usually 3

 

Any chance you know what the capacitance and voltage values of those caps are? I am getting ready to make an order from Digikey, might as well throw those into my cart. Just by looking at them, looks like they are 2mm lead spacing. I can post links to them later.

 

No, as Ford used different value caps

You can Google: Ford EEC-IV Capacitor repair kit

See if they list the values of the 5 or 6 caps included in the kit
If you can get the uF values then just get them all in 100v I don't think any are higher than that

 

sorry about the super late reply. But you're correct. That is exactly what was wrong with the truck. But I just went ahead and replaced the whole ecm. And the truck has been running beautiful since then. So thank you.

 

Thanks for the update, it WILL help someone else down the road