Truck stutters and turns itself off intermittently

[shr3dd3r 09]

I've been troubleshooting this problem for several days now and I am running out of things to check. My 2000 Ranger 5.0 does not want to run well. It will stutter randomly and sometimes it will die completely while idling or driving.

Fuel pressure drops when this happens. I have checked the inertia switch, fuel pump relay, and verified that the pump is getting power to it. The fuel pressure also remains high for several minutes after I shut it down, so I assume the pressure regulator is good.

To date I have replaced the fuel filter and fuel pump and the problem continues. When the truck does die I can still hear the fuel pump running until I turn the key off. When the pressure does drop the power to the pump remains over 13 Volts constantly, so I don't think power is getting interrupted.

It is not losing electrical power completely, because the dash lights, head lights, etc. stay on. I am stumped but I really need to fix this ASAP. What else should I check?

 

[RonD]

Drive without the gas cap tight, could be building up negative pressure, can't pull fuel out of the tank.

What PCM are you using?
Can you check it for any codes that may be stored but didn't set CEL(check engine light)

Flat out dieing is usually injectors or spark stopping, so PCM or similar.
CKP(crank position) sensor can cut spark and fuel, but they are usually not intermittent, wire for the CKP could be an issue, that could be intermittent.

Stumbling then dieing would be fuel related, the PCM grounds the injectors to fire them, check grounds near PCM

 

[XionicWaste]

Pull your Mass Airflow Sensor. The sensors can build up dust and debris and throw off everything, sounds like your problem. You should be able to visually see if it is dirty after you pull it. Let us know if this fixed it!

 

[shr3dd3r 09]

Mass airflow sensor is clean. I cleaned it a while back and it is still in good shape. The grounds looks good at first glance, but I have not checked the wiring to the crank position sensor. I guess I can check the resistance in the wires and see if they are open-circuited.

The CEL is not on, but I will scan it to see if there are any codes present.

 

[shr3dd3r 09]

Drive without the gas cap tight, could be building up negative pressure, can't pull fuel out of the tank.

What PCM are you using?
Can you check it for any codes that may be stored but didn't set CEL(check engine light)

Flat out dieing is usually injectors or spark stopping, so PCM or similar.
CKP(crank position) sensor can cut spark and fuel, but they are usually not intermittent, wire for the CKP could be an issue, that could be intermittent.

Stumbling then dieing would be fuel related, the PCM grounds the injectors to fire them, check grounds near PCM

I am using the engine and wiring harness from a 2000 mercury mountaineer.

It usually stumbles a few times while driving before it will finally just turn off completely out of the blue. Occasionally it just flat out dies with no warning. It also happens independent of engine load.

I'll give your suggestions a try tomorrow and let you know.

 

[RonD]

What did you do about the EVAP system when you did the swap?

I don't see that the mountaineer used an EVAP system, did you hook that system back up, or seal up the vent tube?

The EVAP system is the vent on the Rangers fuel tank, gas cap seals the tank and if the EVAP is not working.........this would normally through a code about the tank pressure being too high or too low.
A loose, or no, gas cap should through a code as well.

 

[shr3dd3r 09]

What did you do about the EVAP system when you did the swap?

I don't see that the mountaineer used an EVAP system, did you hook that system back up, or seal up the vent tube?

The EVAP system is the vent on the Rangers fuel tank, gas cap seals the tank and if the EVAP is not working.........this would normally through a code about the tank pressure being too high or too low.
A loose, or no, gas cap should through a code as well.

I did not do anything about the EVAP system. It is still all hooked up. I haven't heard of anyone doing a 5.0 swap having trouble with that. Also, this problem has only been happening for the last three weeks of the four months the motor has been in the truck, which lead me to think it was either the fuel pump, wiring problem, or sensor failure. Fuel pump has been ruled out, so I'll be checking the cam sensor and crank sensor today.

 

[shr3dd3r 09]

Okay, so I drove around today to recreate the problem and sure enough it died on me several times. However, at one point the check engine light came on and it started running rough and pouring blue smoke. I shut the motor off, turned it back on, and the CEL went away and no blue smoke. Haven't had that problem since. It appeared that it started pouring way too much fuel in causing it to smoke. I scanned it for codes and this is what I got...

P1356 - PIP signal present with engine not running
causes: crank sensor or pick-up coil

p1451 - canister vent solenoid circuit malfunction
causes: bad vent solenoid or open or short circuit

Lots of O2 sensor codes as well, probably because of the above codes.

O2 sensors, plugs and wires, fuel pump, fuel filter are all brand new.

Since it is stalling randomly and it started smoking until I re-started due to too much fuel, I'm thinking the crank sensor needs replacing. I don't know about the vent solenoid. What do you think?

 

[RonD]

P1356 could also be the ignition module failing.
That is an interesting code, a few things could be causing it.

The vent solenoid can be cleaned, pain to get off the hoses though, heat them up to soften and they will come off.
The connector should have 12v on one wire with key on, the PCM grounds the other wire to activate the solenoid, so you can apply 12v with ground to test that the solenoid is working.


Yes, the smoke could be the spark cutting off then restarting, or injectors open too long, although the P1356 would push me in the ignition system direction.
Not sure if your computer runs injectors individually or in banks or switches from one to the other if there is a problem.

 

[shr3dd3r 09]

P1356 could also be the ignition module failing.
That is an interesting code, a few things could be causing it.

The vent solenoid can be cleaned, pain to get off the hoses though, heat them up to soften and they will come off.
The connector should have 12v on one wire with key on, the PCM grounds the other wire to activate the solenoid, so you can apply 12v with ground to test that the solenoid is working.


Yes, the smoke could be the spark cutting off then restarting, or injectors open too long, although the P1356 would push me in the ignition system direction.
Not sure if your computer runs injectors individually or in banks or switches from one to the other if there is a problem.

I went on and ordered a crank sensor. I will put it on in the morning. It's pretty easy to change so I might as well do it since it's a possible cause. If that doesn't do the trick, I'll try your suggestions and let you know.

 

[RonD]

Yes, I would be interested to know if it's the CKP, never ran into an intermittent one, dead or working are the only ones I have come across.
Connectors and wires can cause intermittent issues.

I assume this is a 5.0l from a 2000 Mountaineer

 

[shr3dd3r 09]

Yes, I would be interested to know if it's the CKP, never ran into an intermittent one, dead or working are the only ones I have come across.
Connectors and wires can cause intermittent issues.

I assume this is a 5.0l from a 2000 Mountaineer

Yes it is.

And I will also measure the resistance in the wires to verify the circuit is functioning as it should.

 

[shr3dd3r 09]

Verified that the CKP and CMP wiring is good. Each wire has good connection to the PCM. Still could be the sensors themselves, but I will be changing the CKP sensor here in about an hour.

 

[shr3dd3r 09]

Another thing I might mention... when the truck does die while I am driving it will not start unless I turn the key off and back on. Otherwise it will just crank. Any clues?

 

[RonD]

Another thing I might mention... when the truck does die while I am driving it will not start unless I turn the key off and back on. Otherwise it will just crank. Any clues?

That sure reads like ignition system.
The fuel pump is primed for a second with key off key on but not sure that would restore 0 pressure in fuel rail, especially the 60+psi it runs, 0 pressure would be required for a no-start engine, just low pressure should at least fire a bit.