Hello everyone I'm in diar need of some help I bought a 2001 EXT ranger 4x4 4.0l manual with some very interesting codes saved in the computer
P0302 cylinder 2 misfire
P0125 insufficient coolant temp for closed-loop fuel control
P0171 system lean bank 1
P0172 system Rich Bank 1
P0175 system Rich bank 2
Through my research I believe somehow the P0302 code is connected to the rest of them but not sure how. Can someone please give me some input of love to drive this truck. The coil wire and plug have been changed on the number 2 cylinder and still nothing changes. HELLLPPP!!!!

 

The guy who would be able to help you the most is in Australia, so I'll give it a shot.

That many codes coming up I would start with the mechanical end.

Check your compression, should be at 165, or at least that is what it is for a 3 liter.
At any rate it should be up there.

Check your fuel pressure too, it should be at 65 PSI.

Odd that bank one is showing "lean", and "rich" at the same time.
Lean indicates that there is too much oxygen in the exhaust so not enough fuel is being burned _ so low pressure coming from the fuel pump.

Then you have just the opposite _ "rich" not enough oxygen in the exhaust _ to rich _ too much unburned fuel reaching exhaust.

Could also be bad connections to the PCM and the oxygen sensors _ check connections.
Check you PCM grounds too.
Those wires will be at the fire wall connected to studs.
They will come directly from the PCM engine wiring harness or somewhere close buy.
There probably is another one from the engine itself to the firewall too.

Mine is a 3 liter so I'm sort of guessing here where the locations of things are, but no one is answering and you seem pretty desperate.

 

Thanks brother so I took and got it checked at the local advance auto and they said plugs and coils which have been replaced. Could the misfire be caused by a mixed up wires or something internal? I have alot of mechanical experience but havent delt with many Ford's mostly imports. Also could the coolant temp code be the cause of the misfire? I' at a loss and haven' found anything that points me in the right direction.

 

Start with what I told you, you have to do this logically and rule out any mechanical stuff first like compression and fuel pressure.
You have to make sure those things are with on spec before going after other things.

When you get a cascade of codes coming up like this, especially ones that contradict each other, it's more the likely a mechanical issue and or a wiring problem.
Sometimes just unplugging the PCM and the oxygen sensors will cure things just because it a bad connection.
Simply plugging them back in will fix things.

It's easy to check compression and fuel pressure and compression, start with that.

You never did say if starts and runs.
And if it does run, does it run poorly, hesitate etc... ?

I would imagine with those codes, it runs pretty **** poor, but I need to ask.

To answer your questions.
A coolant temp sensor would not cause those codes, but it may be related. That's used to tell the PCM to open the injectors longer to make the mixture more rich so it will run when cold.
When they fail, it causes poor starting because the PCM thinks the coolant is already hot or they can fail in the other direction, making the PCM think that the coolant is always cold and you get really bad fuel economy.
It's a cheap sensor to replace, so you have nothing to loose there, just be sure and get the right one, don't get the sensor for the temp gauge.

Mixed up wires; check you firing order, it should be on top of the coil box. It's easy to get them mixed up.

Doesn't matter and engine is engine, domestic or import.
Sensors are still the same, just in different locations and even then, not so much.
Eg. MAF (mass air flow) sensor will be right after the air cleaner and before the throttle body in the air intake tube.
CSP (crank shaft position) sensor, always wear the harmonic dampener is etc...
You get the idea.

Know too that sensors don't often fail, the get dirty and or develop bad electrical connections.
Oxygen sensors should be replaced after 70k miles, weather they throw a code or not.
The chemical inside them simply gets used up and they don't give accurate info the PCM anymore.
The PCM won't give codes at this pint because things are still with in spec, but your fuel economy will suffer.

Don't go out and buy some new oxygen sensors though, check you compression and fuel pressure.
You have to rule that out first.

EDIT:
It also may be a good idea to remove the PCM and take the cover off.
Look for burned circuits and or swollen capacitors.
PCMS rarely fail, but not unheard off and with all those codes it should be looked at.

EDIT:
The plugs and coils have been replaced, what about the wires ?
Do you have a multi meter ?
I can tell you how to check them if you do.

 

Yes it runs I drove it home about 30 minutes/ 20 miles. It clears up when ever it wants too but usually runs rough in lower rpms. Never really runs terrile and is so quiet u don' even hear it wen its running. I' going to do the rest of the wires tomorrow and verify the firing order. Seems like a good place too start being I already have them.

 

If it runs as smooth (sometimes) as you say it does, then you're firing order is good.
You may check it if you want though, but I'm pretty sure it's right.
If the firing order was incorrect, it would run poorly all the time.

I'm going to assume you don't have a compression tester or a fuel pressure tester.

Lets assume that you're coolant temp sensor is defective, if that's so, it could be causing the other codes to come up.
If the coolant isn't getting up to temp, or rather the sensor is giving wrong info to the PCM, telling it that the coolant is colder then it really is, then that could be causing the other codes.

Here are some links, it's inexpensive and fairly easy to replace.
The part number is DY1156, get the Ford Motor Craft one.

The sensor will be located somewhere near the thermostat housing and will have TWO wires coming out of out, that's the one to go after.
The other one with "1" wire is for the dash gauge.
You don't have to drain all the coolant out, just to the point below where the sensor is located, about a couple of liters.

http://www.rockauto.com/en/moreinfo....438304&jsn=464

http://www.rockauto.com/en/catalog/f...+/+sensor,4748

And one other thing, clean your MAF sensor, use the special cleaner for it.
It's fragile, don't touch it with your fingers or be tempted to us a Q-tip.

 

Update day 2

SO turns out the firing order on bank 2 was wrong. Fixed that. Had a vacume leak at the intake. The hose that runs all the way around the intake. Fixed that. Runs much better. Cleared the codes but the P0302 (cylinder 2 misfire) is still present. I need valve cover gaskets and there is a lot of oil on both headers could this be fouling the connection on the number 2 plug. I bought the gaskets today gonna take them this weekend sometime. I almost think it' the injector on that cylinder tho the engine has 214xxx miles on it so anything is possible

 

before you replace parts like injectors, and coils, swap them with other cylinders. if the problem moves, that part is bad, if it doesn't, your issue lies elsewhere

 

Hey Quinton, thanks for the update.
I would have never thought that the firing order was wrong after all.

+1 on what Dusten says.

 

FML 😠😠😠😠😠

So went and started the truck took the plug out. Had a little oil on the threads so I pluggd the coil to it to see if I could get Spark and all of a sudden I begin to get a tapping noise out of the head I'm starting to think I bought a dud but for 500 bucks I guess I can't complain on to the next journey I guess I really want to drive this truck

 

Day 3 update

so today has thrown me a new monkey wrench. Went from smooth running to ticking under the passenger side valve cover. The P0302 is still there but also the P0171 came back. I'm lost and am starting to think it' been a mechanical issue all along

 

Day 4 update

I fixed the tick turns out it was just a bad coil wire that was grounding out to the block. Swapped it out and the tick went away and the p0171 lean code is gone as well. Back to the drawing board gonna do a compression test tomorrow. Hope that can tell me something good.🤞🤞🤞

 

Dude fixed it turned out to be an injector and cylinder 1 was a cracked spark Plug I'm suck a dunce lol cheers brothers