Electrical problems - fuel pump relay

[45-70]

Hey all!
I'm at a roads end with getting my ranger 2.9 -88 running again. It just died on me when starting it up after winter.

I think I have located a problem, but dont know how to poceed. The fuel pump relay semes to work just fine, but the signal to it is funky. When I turn the key I get 12v on both terminals on the signal/activation side (fuel pump side is fine). Not for two seconds either, but continously. With a positive 12v on both sides the switch obviously won't activate. (Jumping it the pump works fine).

How do I proceed? I'm at a loss, and electrical stuff at large messes with my poor ol' brain.

Is my engine brain shot? It runs on starter gas/breaklean.

(I'm Swedish, so my technical vocabulary isn't the best. But I'm not as stupid as I might sound... )

 

[Uncle Gump]

The ignition side of the relay receives power from the EEC relay with key on. The ECM will then ground the relay control circuit for 3 seconds to prime fuel system. Once ECM sees the engine is running... it will ground the control circuit again to turn on the fuel pump.

If you're checking for power with the relay connected while back probing the connector... it appears your ECM is not grounding the control circuit... or the control circuit is open between the relay connector and the ECM.

 

[Uncle Gump]

I should add... I did scrub the f-bomb out of your post. We try to keep that off the forum pages. Because that's the way the owner wants it.

Carry on... enjoy and welcome to TRS...

 

[rusty ol ranger]

Sounds honestly like an ECM problem.

Order a innova EEC IV code reader.

I had a similar problem a very long time ago with my ranger, i ended up hotwiring the fuel pump to the key switch.

Years later i took that ECM and put in my current ranger, and had no fuel pump.

Pulled code 95 i believe.

But yeah...sounds like ECM.

 

[45-70]

Thanx a bunch!
So it"s ok to hotwire the relay so the pump is on all the time the ignition is on? If I pull the wire from the switch to the ECM and just ground it that would be the result I figure. That way I don't disable the inertia switch, which feels safe (as long as it doesn't break).

 

[45-70]

So I cut the wire to the electronic control assembly (no 22, tan/lt green) and put it to ground instead. Left terminal 22 on the ECM empty. The fuel pump is now running full time when key turned.
I still got no life from engine. I can make it run on starter gas, but not a single cough on gas.

If my ECM/electric control assembly is shot the feul injection wont work, right? So I need a new one. Can I rule out shortage/grounding issues someware else that cause the ECM to behave like this?

Can anyone please help me find where to buy an ECM that will ship to Sweden/Europe? I can't find one here. A used one would be best cus then I dont think I need to pay costom fees.

 

[rusty ol ranger]

So I cut the wire to the electronic control assembly (no 22, tan/lt green) and put it to ground instead. Left terminal 22 on the ECM empty. The fuel pump is now running full time when key turned.
I still got no life from engine. I can make it run on starter gas, but not a single cough on gas.

If my ECM/electric control assembly is shot the feul injection wont work, right? So I need a new one. Can I rule out shortage/grounding issues someware else that cause the ECM to behave like this?

Can anyone please help me find where to buy an ECM that will ship to Sweden/Europe? I can't find one here. A used one would be best cus then I dont think I need to pay costom fees.

The ECM grounds the fuel injectors to fire them. The 2.9 is batch fire meaning it shoots off 3 injectors at a time.

Before i went any further i would get a fuel pressure tester and check pressure at the rail. Should be 40psi.

If you have 40 psi at the rail then it sounds like you have a failed ECM.

I have no idea how to get one over where you are. Maybe ebay? Get one shipped from here? But i also dont know if there are ecm differences in programming from US and overseas models.

@RonD any idea?

 

[45-70]

The ECM grounds the fuel injectors to fire them. The 2.9 is batch fire meaning it shoots off 3 injectors at a time.

Before i went any further i would get a fuel pressure tester and check pressure at the rail. Should be 40psi.

If you have 40 psi at the rail then it sounds like you have a failed ECM.

Thank you! I'll do that!

I have no idea how to get one over where you are. Maybe ebay? Get one shipped from here? But i also dont know if there are ecm differences in programming from US and overseas models.

@RonD any idea?

I have an imported ranger, but not sure if it's a California model. Dont think so. There is no emission requirements for this car.
I hear it does't matter if the ECM is from a 2x4 or 4x4, but need to be for automatic gearbox not manual. Correct? The lable reads E8TF-12A650-U1C. I may have found a used one in Poland. Might take the chance on that after I check the fuel preassure.

 

[rusty ol ranger]

Thank you! I'll do that!



I have an imported ranger, but not sure if it's a California model. Dont think so. There is no emission requirements for this car.
I hear it does't matter if the ECM is from a 2x4 or 4x4, but need to be for automatic gearbox not manual. Correct? The lable reads E8TF-12A650-U1C. I may have found a used one in Poland. Might take the chance on that after I check the fuel preassure.

Yes, if its like the ones in the states it only matters what trans you have (manual or auto) and if its california emission or federal emissions.

88-92 ECM's should be the same. 86/87 ECMs will look for an EGR and knock sensor input that your truck dont have being an 88.

 

[Curious Hound]

This could be a loose/dirty ground issue. I would check all ground connections thoroughly before buying a new ecm.

 

[45-70]

This could be a loose/dirty ground issue. I would check all ground connections thoroughly before buying a new ecm.

You where right!!
I had ben starting to suspect it an checked the most obvious points, but thought a microchip would just shut down from it, not set a terminal hot that should not be. I guess it's more rudimentary electronic in that box
Anyway, you gave me one more puch and I found it! It was actually the ECM main ground (terminal 40 and 60) cable that was broken in the engine bay exiting the harness.

You guys are the best! Thank you!! The ranger purrs like the little cat she is again.

 

[Curious Hound]

Congratulations. Always feels good when you get it fixed.