The never ending P0171 lean code 97 2.3l ranger

manny2294 · #1 10-29-2017, 08:13 AM

ranger.

Hey guys, I've had my truck for about a year. And since I've had it, it's had the exact same lean code. I have replaced the MAF 4 times already. I replaced the tps, iac, coil packs, plugs, wires, crankshaft sen,*camshaft*sensor, AND the computer. I've also had the car smokes a few time, with no leaks detected. I have a steady misfire with no code for it, and when I'm driving in neutral, the idle will stay at 2000-3000 rpm until I make a complete stop. I've also replaced the fuel rail, fuel injectors, fuel regulator, and fuel pump. I seriously do not know what else it could be at this point? Is my truck out of time? Any insight would be helpful right now. I bought better plugs, wires, thermostat,*timing*belt, and tensioner this weekend and I'm installing all of them Tuesday. If anyone has any ideas, I'm all ears.*

Thanks

manny2294 · #2 10-29-2017, 08:13 AM

Heres the code.

stateranger · #3 10-29-2017, 05:12 PM

Start looking for bad vacuum hoses. Smoke tests can miss alot.

atikovi · #4 10-29-2017, 05:24 PM

Had that code and found one of the larger rubber vacuum hoses to have cracks.

manny2294 · #5 10-29-2017, 08:46 PM

I've smoked the thing twice (cold and hot) and I've wasted God knows how many cans of brake cleaner on it. It's not a vaccum leak. Hell, I wish it was. Thanks for the replys guys.

atikovi · #6 10-30-2017, 04:34 AM

Just how are you smoking it? What does brake cleaner have to do with it?

tomw0 · #7 10-30-2017, 06:19 AM

QUOTE:it's had the exact same lean code. I have replaced the MAF 4 times already. I replaced the tps, iac, coil packs, plugs, wires, crankshaft sen,*camshaft*sensor, AND the computer. I've also had the car smokes a few time, with no leaks detected. I have a steady misfire with no code for it,

Well, you explain the lean code with the steady misfire. If you have misfire, the oxygen that would normally be consumed in combustion goes right out the exhaust pipe past the O2 sensor to the converter. On the way, the O2 sensor says, surprized-like, "Wow, there are a lot of extra O2 molecules that were not burned. Hmmm. The mix must be lean, as otherwise, if correct, there would be NO extra O2's. I think I'll tell the computer that it needs to pump up the juice so all O2's get burned, as it MUST be a LEAN condition."
Being a dummy, the O2 sensor just senses O2's and not misfire, and reports what it senses. A casual observer would note the misfire, and fix that before concerning with other problems that may be indicated, but in actuality relate to the original non-fire condition.
Fix the misfire, and the other things may disappear. You might have a recessed valve seat that causes misfire at slower rpms, but 'disappears' at higher rpms. I'd check compression in all cylinders, plug wires, plugs, and take a look at the plug condition at the working end in an attempt to isolate the offending cylinder.
tom

The Ford Ranger · #8 10-30-2017, 07:06 AM

Quote:

Originally Posted by tomw0

QUOTE:it's had the exact same lean code. I have replaced the MAF 4 times already. I replaced the tps, iac, coil packs, plugs, wires, crankshaft sen,*camshaft*sensor, AND the computer. I've also had the car smokes a few time, with no leaks detected. I have a steady misfire with no code for it,

Well, you explain the lean code with the steady misfire. If you have misfire, the oxygen that would normally be consumed in combustion goes right out the exhaust pipe past the O2 sensor to the converter. On the way, the O2 sensor says, surprized-like, "Wow, there are a lot of extra O2 molecules that were not burned. Hmmm. The mix must be lean, as otherwise, if correct, there would be NO extra O2's. I think I'll tell the computer that it needs to pump up the juice so all O2's get burned, as it MUST be a LEAN condition."
Being a dummy, the O2 sensor just senses O2's and not misfire, and reports what it senses. A casual observer would note the misfire, and fix that before concerning with other problems that may be indicated, but in actuality relate to the original non-fire condition.
Fix the misfire, and the other things may disappear. You might have a recessed valve seat that causes misfire at slower rpms, but 'disappears' at higher rpms. I'd check compression in all cylinders, plug wires, plugs, and take a look at the plug condition at the working end in an attempt to isolate the offending cylinder.
tom

Hi. I had same code same problem with mine.it started with maf. Replaced same code,replaced the map. Ck engine lite stayed on. I let a few weeks go by bc I was frustrated with the whole thing. Went n had engine scanned again and oxygen sensor now comes up. My engine was missing on low rpms. I ordered. Both 02 sensors,only bc truck has 237000 miles. I doubt they were changed b4 . Hopefully that will solve my problem.. maybe yours to. G.L.

DangerRanger37 · #9 10-30-2017, 03:20 PM

injectors. That's what did if for me.

manny2294 · #10 10-31-2017, 03:55 PM

Thanks guys. Well, I changed all my plugs and wires and took the front end of my truck apart to check the timing. The timing is fine. I've had the first o2 sensor replaced, I also had all 4 injectors replaced about 6 months ago. The truck is still missing after plugs and wires. So I'm at a loss. I'm thinking of buying an o2 delete thing. That tells my ecu that the O2 is reading everything fine. I don't know if I should though.

manny2294 · #11 10-31-2017, 07:39 PM

Quote:

Originally Posted by atikovi

Just how are you smoking it? What does brake cleaner have to do with it?

I sprayed brake cleaner on the engine looking for leaks and change in idle. I had it smoked through the intake, as well as the EVAP system.

EaOutlaw1969 · #12 11-01-2017, 03:24 AM

Quote:

Originally Posted by manny2294

ranger.

Hey guys, I've had my truck for about a year. And since I've had it, it's had the exact same lean code. I have replaced the MAF 4 times already. I replaced the tps, iac, coil packs, plugs, wires, crankshaft sen,*camshaft*sensor, AND the computer. I've also had the car smokes a few time, with no leaks detected. I have a steady misfire with no code for it, and when I'm driving in neutral, the idle will stay at 2000-3000 rpm until I make a complete stop. I've also replaced the fuel rail, fuel injectors, fuel regulator, and fuel pump. I seriously do not know what else it could be at this point? Is my truck out of time? Any insight would be helpful right now. I bought better plugs, wires, thermostat,*timing*belt, and tensioner this weekend and I'm installing all of them Tuesday. If anyone has any ideas, I'm all ears.*

Thanks

manny2294 You have spent way too much time and money installing parts and not enough time that I can tell with basic diagnostics.

At least you did not tell us about the diagnostics you performed other than a smoke test ( Which may have been done improperly )

Spraying brake clean for use as a leak detection method could prove worthless if the brake clean is the non flammable type.

The very first thing I would do with any engine that is running rough or misfiring with codes or not would be a compression test.

You need to make sure all four cylinders have good compression.

One you know the compression test reading for each cylinder post your results here.

As far as the lean code P0171 if the compression test is good I would perform all the factory pin point test for this code until I diagnosed the problem.

With a Service manual a DVOM and basic hand tools this code should not take more than an hour or two to complete.

I have got to think at some point people like you would read enough post on this and other forums about how to properly diagnose a trouble code.

If your here because you want a magic part to fix your truck with little or no effort on your part I am 100 % positive you will be disappointed with the amount of time and money you will waste trying to fix your truck with the little tid bids of information you will get here.

Very rarely do problems and or trouble codes lead to the same part being bad from vehicle to vehicle ( yes it happens but it is not worth wasting time and money hanging parts on a vehicle to find out )

If they did automotive part manufactures could sell their parts by the trouble code it could fix.

Long story short, if you want help that will actually help you fix and understand what is wrong.

Buy a factory service manual or online subscription to one, read the entire pin point test for the code your having to get an idea of what tools and test equipment you will need to diagnose your code.

If you have any problems running or understanding these test, this is what we are here for, to guide you though the process of diagnosing and properly repairing your truck.

manny2294 · #13 11-01-2017, 06:32 AM

Where can I get a factory service manual?

tomw0 · #14 11-01-2017, 06:58 AM

You may find one on ebay or similar. Your library may have them on the shelf, and you may be able to copy pertinent pages. Your library may have access to "EBSCO" or another site with information specific to your truck. You should find the 'likely suspects' for the codes mentioned by searching for the P0xxx codes along with "Ford", i.e., "Ford P0171 code" will return a pile of sites that explain specific codes.
A compression test would indicate if the 'mechanical' parts of the engine are working, and how well. Pistons, rings, cylinders, connecting rods, head, head gasket, valves just to name the ones that make an engine able to function. I think.
Get the engine hot, remove all the spark plugs, or if 8-plug, just the exhaust plugs, disable the fuel pump(pull relay wires or rollover), disable the sparker, and prop the throttle wide open. Install the gauge hose finger-tight into one of the spark plug holes. Connect the gauge to the hose, crank the engine over ~4-5 times, observing the gauge. The gauge will 'pump up' on the first 2-3 cycles, and reach a plateau. Record that number, release the pressure and go on to the next cylinder. Repeat for all.
Rule of thumb(as hit by hammer) is the pressures should be within about a 10% range of each other. Closer indicates there are no 'problem' cylinders. If two adjacent cylinders have poor compression, a likely cause is a blown head gasket between the two.
If the pressures are low, pouring a Tbsp of engine oil into the cylinders and re-checking, can be done to see if the pressure comes up significantly. If it does, leaking rings that the oil seals temporarily is the most common Dx. If the pressure does not come up, the rings are likely judged 'good'.
A leakdown test is even better to diagnose the problem.
tom

atikovi · #15 11-01-2017, 08:10 AM

Quote:

Originally Posted by manny2294

Where can I get a factory service manual?

On Ebay. Get the factory DVDs like https://www.ebay.com/itm/1999-1996-F...FZiwLM&vxp=mtr The only issue is you have to set back your computer clock everytime you use it.