1991 2.9 manual ranger rough idle and dies

[preston c]

yes it idles at a lope almost.I will check those and get back with you

 

[preston c]

i went out today to check the ignition timing but got side tracked. it’s throwing code 21 again which is ect out of range. Turns out the pin is pushed to the back of my connecter. Could this cause the rough idle?

also how do you get ur motor to TDC to check ur ignition timing

 

[rusty ol ranger]

i went out today to check the ignition timing but got side tracked. it’s throwing code 21 again which is ect out of range. Turns out the pin is pushed to the back of my connecter. Could this cause the rough idle?

also how do you get ur motor to TDC to check ur ignition timing

The ECT basically works like a choke. It tells the ECM the coolant temp so the ECM can decide if the engine needs to be rich (cold) or it can be leaned out (warm).

If that signal isnt getting to the ECM it could for sure cause issues.

I would fix that and try it.

As far as checking timing, it doesnt need to be at TDC (unless you have pulled the districutor and are now reinstalling)

On the harmonic balancer there will be marks for timing. You may need to clean them off after 40 years of grime accumulation.

Find the mark for 10* BTDC (or 12, some guys run 12, i run 10 as its what the factory calls for), mark this line with something highly visiable (i use a white paint marker).

Get a timing light, itll have 3 wires. The alligator clips go on their respective sides of the battery and the other one goes on the #1 plug wire.

Remove the SPOUT connector (its a little plug with green and yellow wires running to it up on the upper intake, passenger side, the part that says "2.9L electronic fuel injection").

I should add engine should be warm before testing.

Loosen the distributor (just enough to turn, but not enough to rattle around in a circle)

Fire it up and point the timing light at the harmonic balancer, the light should flash when your timing mark lines up with the timing pointer on the engine. If it doesnt, adjust distributor untill it does.

Kill the engine, tighten distributor, reinstall SPOUT, and test drive

 

[preston c]

I got a fuel pressure tester, tested the fuel pressure and it to where it says it should be. I looked it up and it said from 35 psi to 40 psi and it stays at about 40 the whole time and does not lose pressure but I did realize when trying to start the truck the green relay I think it’s the fuel pump relay clicks continuously. If leave the key turned over for a little bit while the engine is off the relay will click continuously also. The truck does not want to start when but when it does, It will run for a few seconds then you hear the relay clicking continuously again and then the truck dies. Could this be a wiring problem or bad relay? Could this cause my issue?

 

[rusty ol ranger]

I got a fuel pressure tester, tested the fuel pressure and it to where it says it should be. I looked it up and it said from 35 psi to 40 psi and it stays at about 40 the whole time and does not lose pressure but I did realize when trying to start the truck the green relay I think it’s the fuel pump relay clicks continuously. If leave the key turned over for a little bit while the engine is off the relay will click continuously also. The truck does not want to start when but when it does, It will run for a few seconds then you hear the relay clicking continuously again and then the truck dies. Could this be a wiring problem or bad relay? Could this cause my issue?

It should just click on once to run the pump with the key on engine off...but youre getting good fuel pressure...if the relay waa bad i would think it wouldnt run the pump and you would have no pressure.

You can try the relay...but im wondering if its ECM related.

 

[preston c]

It should just click on once to run the pump with the key on engine off...but youre getting good fuel pressure...if the relay waa bad i would think it wouldnt run the pump and you would have no pressure.

It should just click on once to run the pump with the key on engine off...but youre getting good fuel pressure...if the relay waa bad i would think it wouldnt run the pump and you would have no pressure.

You can try the relay...but im wondering if its ECM related.

before i start throwing more money and parts at it what could i check? I plan on checking grounds, but idk what else.

 

[rusty ol ranger]

It could be a ground. But i believe the fuel pump relay is grounded in the ECM...it trips it to run the pump.

@RonD is much better at electric then me

 

[RonD]

Yes, disconnected ECT will set code 21 Engine Coolant Temperature (ECT) sensor out of range – ECT

You know where the OBD1 test connector is
Drawing here shows the Fuel pump slot on the connector: https://www.therangerstation.com/tech_library/images/eec-iv_testing2.gif

That slot is the Ground for the fuel pump relay, that slot is connected to pin 22 on computer and the ground pin on Fuel Pump Relay

Turn the key on, engine off
Fuel pump relay should just click one time, 2 seconds on then off
Ground that slot with a jumper wire
Relay should click on and stay on, fuel pump is on
If it starts to click then a problem is with relay OR its 12v side of the coil

No clicking
Start engine
See if it runs any better
While its running remove jumper
If relay starts to click again then a problem in the computer or its pin 22 wire to that slot on OBD1 connector

 

[preston c]

Yes, disconnected ECT will set code 21 Engine Coolant Temperature (ECT) sensor out of range – ECT

You know where the OBD1 test connector is
Drawing here shows the Fuel pump slot on the connector: https://www.therangerstation.com/tech_library/images/eec-iv_testing2.gif

That slot is the Ground for the fuel pump relay, that slot is connected to pin 22 on computer and the ground pin on Fuel Pump Relay

Turn the key on, engine off
Fuel pump relay should just click one time, 2 seconds on then off
Ground that slot with a jumper wire
Relay should click on and stay on, fuel pump is on
If it starts to click then a problem is with relay OR its 12v side of the coil

No clicking
Start engine
See if it runs any better
While its running remove jumper
If relay starts to click again then a problem in the computer or its pin 22 wire to that slot on OBD1 connector

okay thank you! could this relay issue cause the problems i’m having?

also i put connecter on ect and connected it and it didn’t fix the running conditions, but it took away code and check engine light. does it matter which wire goes to what or is just the resistance between the wires?

 

[RonD]

Just the resistance between the 2 wires

Idle should be higher with Rich mix when engine is cold and then come down over the next 5 min or so until it warms up, that's Choke mode
That's what the ECT is for

That's when the O2 sensor takes over so computer can calculate air/fuel mix on the fly, O2 can't work until is heated above 650degF by the exhaust

The test on the FP Relay ground is more to see if computer is acting up, pulsing the FP relay ground when it should be on full time(when engine is running)

Fuel Injectors are also run by computer grounding them, and goofs there COULD cause rough running

 

[preston c]

Just the resistance between the 2 wires

Idle should be higher with Rich mix when engine is cold and then come down over the next 5 min or so until it warms up, that's Choke mode
That's what the ECT is for

That's when the O2 sensor takes over so computer can calculate air/fuel mix on the fly, O2 can't work until is heated above 650degF by the exhaust

The test on the FP Relay ground is more to see if computer is acting up, pulsing the FP relay ground when it should be on full time(when engine is running)

Fuel Injectors are also run by computer grounding them, and goofs there COULD cause rough running

I cleaned the connecter and relay because it had a lot of corrosion and now the relay only clicks once like it should now. The truck started and relay was fine too, the truck was a little hard to start but when it did it ran good four about 2 minutes then started sputtering and died again.How can i check out the injector problem? Sorry about all the questions. But this truck has me lost

 

[preston c]

I realized the relay was really corroded along with the connecter so i cleaned the corrosion and it hasn't clicked rapidly since, idk if that was a problem or just a coincidence. how could i test the injector problem?

 

[RonD]

And the other relay, EEC brown base?

That one powers the injectors