I need help on my truck. Background info. : Last summer replace the IAT because it was making a howling noise from air filter to intake, intermittingly. $ If it matters; Worked on the AC with new compressor and dryer and hi/low hoses, etc. worked 2 months and stopped but has refridgerant pressure in lines? $$$$ Once in a while, would get trouble code p 0701 lean bank one. Then ignition key wouldn't work so I replaced it with air filter.
Now, last couple months I get lean on bank one, lean on bank two. And SSB (shift selonoid B) trouble code shows up for transmission. As well as a it has a delay in engaging drive from park. That drives me crazy. I ended up replacing the valve body gaskets upper and lower and the EPS, TSP, SSB,SSD. $$$$$ And no improvement in the delay but shifting and down shifting is a lot better as long as the MAF is plugged in. Otherwise shifts hard and the rear end takes the brunt.
Back to the engine. Replaced the battery, plugs, wires. $ Then at idle engine starts to surge and it reflects that in the RPM gauge. 600-1200 for 4 to 8 cycles and stalls, sometimes, and others it returns to normal. So I replace the PVC and checked vacuum lines they were good but I replaced them anyways. $ And at this time it starts to surge while driving come coming to a stop or at a stop. Then starts stalling out after surging. And I can hear the trans and drive line clanking against the rear end as the rpms bounce. progressively.
I have replaced the fuel filter, fuel pressure regulator, vaccum lines to charcol canister and the in line check valve and selonoid and canister. $$ No change in performance but the smell of gas in the cab has been eliminated, from canister. Oh did front pads and rotors around this time. $$ Next I replaced the fuel rail gasket,upper and lower, valve cover gaskets and intake manifold gaskets. And cleaned the injectors and new rubber on those. As well as cleaned up the wire harness added conduit and tape, etc. $$ Change in performance but its much more quiet and smooth and the intensity of surging and stalling a lot less. Now stalls and you dont feel or hear it, at a light and it turns green, step on gas and nothing cause it stalled. And only does it sometimes, Soooo , I replaced the MAF after cleaning it to begin with, way back with vacuum lines. I was reluctant but did it cause it to shifted smoother, anything to help the trans at this point. $ And now the f%$^&*(( wants to start stalling 3 out of 5 lights. I checked the plugs and none looked fouled out. The O2 sensor and radiator was replaced before I inherited this money pit ( every $ is a hundred dollars). Once I am driving along, and even on the freeway, she runs great, very nice. There has been no excessive fuel consumption. The exhaust is clean, no smoke or gas smell. Now I have a new motor and accessories basically but the original problems exist. IF its not one thing.............. 3 others. What's left or what did I miss or why did all the troubling shooting and reading not help point out the problem.

 

1997 ford ranger xlt, 4.0, v6, 4x4. 255,575 miles. 5r55e trans.

 

Welcome to the forum

When you unplug a Main sensor, like MAF, the computer(PCM) will run an automatic trans in Safe Mode, often called "limp mode"
This means hard shifts which is actually safer for transmission, smooth shifts require the clutches and brakes(bands) in the transmission to slowly engage, and if there is a problem then they will burn out over time, so Safe Mode is better if PCM detects a problem, of any kind, in drive train.

Slow to engage Reverse in any automatic means pressure in the trans is too low, Reverse requires the highest pressure, which is why Reverse is often lost first in automatics.
The Pressure to engage clutches and brakes comes from the Front Pump(main pump)
Front pump is connected to the torque converters outside case, so spins at engine RPMs.
If you increase engine RPMs then you increase the speed of the Front Pump and so increase the pressure in the transmission, and you can sometimes get clutches and brakes(gears) to engage.
Pressure is lost from internal leaks, changing Valve Body can get rid of most of those leaks, but not all, and lower pressure would have worn out clutches and brakes, maybe to the point of rebuilding.

Around 1985 automatics started to get TCC solenoids, it locked torque converter while driving for better MPG and power, but it has to unlock when you stop or engine will die.
So try shifting to Neutral before stopping to see if the stalling is TCC related, or engine/PCM related, engine would still stall if problem is engine or Computer related


Here is an easy check for vacuum leaks on fuel injected engines, they all use IAC(idle air control) Valves.

Warm up engine fully, let it idle
Unplug IAC Valve's 2 wires, it will close all the way.
Engine RPMs should drop to 500, or engine may even stall, either is GOOD, it means no vacuum leaks.

If RPMs stay high then there is still a leak.

 

Ok I can follow that and it makes sence. But you said reverse and it is drive that has the delay and when I am waiting for it to engage, if i tap the gas it seems to speed up the engagement like you described. But then hits hard and I try not to do that. In my original statement I said EPS and TSP because I couldn't remember TCC and the other one. But I put in four new selonoids all on the one side. I did not put in a new SSA or SSC. I believe the clutches are worn out. Although there was no metal in bottom of trans pan there was a black soot like that of worn break pads when you wash the front wheels of the truck with a hose. And the fluid was burnt. Had the smell in my cab for two days. When I unplug the IAT it goes into that surging state. Or stalling state trying to recover. I say that cause at night when it happens my lights and dash go dim then back up and so on. honestly I dont think there is a vacuum leak at all. there is only what 6 little lines and all are fine and the original gaskets looked ok although on valve cover was seeping out oil like any normal 20 yrold would. but that is fixed. what is the next step?

 

Nuetral... I have to go for a drive so I will trythat and get back to you. ty

 

So at a stop when it starts to surge I put it in nuetral and it returns to normal idle. Also before when at a stop when it acts up I would put on foot on break and just tap the gas to bring the Rs up and that would smooth it out. If the idle was adjustable I would have just brought it up but thats not a fix. whats next.

 

Test for vacuum leak, do the IAC test, it is free.

Right, an idle screw can't work with fuel injection, no idler jets like on a carb, so IAC Valve is used, and it works very very well, until it doesn't, and that can be the valve itself or mixed messages to the computer, i.e. "garbage in, garbage out" computer programmers mantra

If only Forward is slow to engage then could be a few things, try shifting directly to 1st instead of drive and see if it engages faster.

If trans fluid smelled burned then transmission needs a full rebuild, no way around it, I wouldn't waste time on non-fixes for that, just drive it until it dies and look for a good rebuild price.

Heat kills all automatics, so 2nd trans cooler is not an option, best $60 you will ever spend on any vehicle with an automatic.

 

RonD thank you for your help. i really appreciate it. Sond troubleshooting and a vast knowledge of this topic are a relief for me. Also for being straingt forward on the fix that is what it is. A second cooler will be done. Have a great day andtalk to u agian.

 

Your idle issue is not related to trans slow engagement.

If it idles normally if you shift to Neutral prior to stopping then check the DTR sensor connection.
DTR(Digtal Transmission Range) sensor, it is on the transmission, drivers side, on the linkage, it tells computer "what gear" was selected, unplug the wires and make sure connector is clean, no frayed wires then plug it back in.

Also test that TPS(throttle position sensor) is hooked up.
Engine off
Key on
Press gas pedal down to the floor and hold it down all the way
Now turn key to START
Engine should NOT start, it will just turnover, it has no gasoline coming in
If it does start then check TPS Connector, 3 wires, unplug and check for clean and dry

When engine is off and key is on you can put computer into "Clear Flooded Engine" mode, not a Ford thing, all fuel injection computers have this
With gas pedal to the floor the TPS should be sending computer 4.5-5.0volts(WOT-wide open throttle), and if RPMs are 0 then computer will enter "Clear Flooded Engine" mode, and turn OFF Fuel Injectors.
So you WILL get a no start, if TPS is working
As soon as you let off gas pedal injectors will start


95% of DIY changing of sensors is not needed, sensors rarely fail, wire connections do, they get dirty and corroded, simply unplugging them and plugging back in often cleans them enough to fix the issue.
But don't feel too bad, 80+% of sensors changed by Pro Mechanics were working fine, they do it out of ignorance or to pad the bill

O2 sensors do wear out they use a chemical reaction so chemical gets used up, but 100-125k miles between changes

And computer monitors all the sensors, so will generate a specific code if data doesn't seem right, but code numbers are not in english, it is in computerese, so NOT to be taken literally.
If you get a code that specifically names a sensor then that sensor is WORKING or problem couldn't be report that way

 

I was just gonna ask why i am getting p171 and p 0174, lean on bank one and two. ok I will check your last instructions out.

 

the DTR wiring is fine. the TPS is good. It did not start up. however while looking at the DTR I noticed that the shift cable itself is missing about a half inch of insulation just before where it locks into a connection clip. I had to move up a heat shield type of conduit to see it. would that have any effect. nexty

 

Yes, when using a cable for mechanical movement, like brakes on a bicycle/motorcycle, then length of the sheath must be fix, can't move, it determines how much travel the cable inside has.
If the sheath is not solid and fixed then IT moves so cable travel varies

 

ok went and got a new shift cable and installed it and made adjustment so it finds all gears. When test driving I did notice that when the engine surges at a stop and I put it in N it does still smooth out. However when coasting up to a stop and it starts surging and I put it in N it will continue to surge until I come to a complete stop. There is no delay, like in D, when I start off in 1 or 2 from park but once it wouldn't pick up once I shifted into D and another time the whole truck shook like the trans was about to drop out of the bottom. I had to let up on the gas and go back into it and it shuttered again. I let off and went back into it and it drove fine. weird. But you mentioned to drive it until the trans dies. I am looking into rebuild cost and turn over time, etc. etc.; So main point, shift cable is in and adjusted and no change in performance so far. Shifts a little nicer, easier, but lets move on.

 

Still have P 0171 and P 0174 codes. Lean on bank one and two. grrr.

 

Did you do the IAC Valve test?

Warmed up engine, idling
Unplug IAC valves 2 wire connector

RPMs should drop to 500 or engine may even stall, either is GOOD, it means no vacuum leaks

If RPMs stay up then there is a leak, leave IAC Valve unplugged and start pulling hoses and plugging intake port with you finger until RPMs drop

For both banks of an engine to show Lean codes it will be upper intake issue/leak.

If RPMs drop to 500 or so then no vacuum leaks and time to loo at other causes.

MAF sensor can get dirty and cause Lean codes

It can also be low fuel pressure, pump or filter issue, but last on the list of things to check

 

Yes did IAc test and rpms dropped and it wanted to stall. actually it acted just like it does when it stalls at a stop. I replaced the uppper intake manifold gasket and the fuel rail etc etc. The old ones looked just fine as far as showing anything blown or leaking. Just got a new MAF sensor last friday and no difference. Replaced fuel filter, fuel pump is fine. So Im at a loss. Gonna try just injector cleaner and see. Vacuumleaks.

 

Lean codes would, in my opinion, be fuel pressure related if there is no vacuum leak.
1997 should run 30-40psi pressure
There will be a Fuel Pressure Regulator(FPR) on the engine, it will have the Return Fuel Line connected to it, and a vacuum hose

There is a fuel pressure test port on the engine, looks like a tires air valve, because that is what it is, a schrader valve just like on a tire
Press center pin down to release pressure
Engine COLD, key off engine off
Be Careful. press down center pin, should still have 20psi or so pressure in there, lasts for a few MONTHS
If no pressure cycle key on and off 3 times then leave it off
See if you have pressure now

If very little then FPR may be leaking fuel back to gas tank, i.e. Return fuel line
Remove FPR's Fuel line, need a special tool to do this be not expensive, or you can make one.
FPR should not allow gasoline to flow out the Return line until fuel pressure is above 40psi
So put a towel down under FPR and cycle key on and off one time
No gasoline should come out of FPR, if it does replace it

 

I replaced the FPR two weeks ago. It had no effect but I will do the test anyways, cause new doesn't mean it works. I also just yesterday pull off the vacuum line that sits in front of the brake booster vacuum line and put my finger over the hole on intake and the motor got smooth, took finger off and it got rough. Its the one with 3 tiny lines on it, one runs to the FPR the other to a vacuum thing that runs another to the EGR and the other runs with the FPR line but breaks over to a round canister on that side of the motor. But I also found oil sprayed on the bottom of my hood above the break resevior. Weird cause I cant see were it came from at all. Only thing over there is the dip stick, which was tight. So I have a haunted truck .....lol.

 

I still have to do a fuel pressure check onthe valve on the rail. so standby for results.

 

Vacuum isn't used up, with one exception....PCV Valve

So if you pull a vacuum line from the intake and then plug that hole it should not effect engine
If it does then that hose has a leak

From your description one of the hoses on that vacuum manifold is leaking

These two often share hose with a "T"
FPR hose
Vacuum Reservoir hose

Then there is
EGR modulator
EVAP modulator

And
Power booster hose
PCV valve hose

PCV Valve is a "controlled" vacuum leak, when engine is idling vacuum is high and it pulls the weight in the PCV Valve up to close the valve inside.
People often shake a PCV Valve and if the weight inside moves then they think it is OK, which for the most part is true, but not 100% accurate test.

 

Mr. RonD;
Well I started to doubt my abilities and was thinking about taking the top side of the motor back apart to check the intake manifold gasket, because the new one did not have the front and back of the gasket as one piece like the original and they gave me a tube of form a gasket to fill in the blank, which I did not like at all. Its about three inches of form a gasket space on each end. I let it dry like 16 hours before starting it up, but then I thought if it was a blow out at these points the engine would run like **** no matter when it was on. So I went down your check list again. PVC is new. The emission tubes, tiny things, were all good but one was brittle and broke when I bent it a little. So I replaced it and all the rubber ends on all the tubes. Started it up and it made no difference. So you referred to intake leak with the codes, as did others, as did the repair manual so I checked the air filter for cracks and cuts. I know I put gaskets in right and tightened them right but I checked for cracks on the plastic. All good. Then it hit me as I was looking at the power steering pump that is pushing fluid out somehow on that side of the motor. What is up with the eternal wyning of the power steering pump on fords btw. And why is there no drain plug on transmissions????
I pulled the EGR off from its intake tube and two mounting bolts and there it wasn't. There was no gasket between EGR and the flow tube up into the intake which is hard to see that tube because of all the stuff right there. And so I have it, The extra air was coming in there between the two metal plates with no gasket.............**** yeah.....It cost me my cereal box to cut two out and put them in. I doubled up on it. She runs fine, in fact the long delay in shifting from P to D is now a very short delay and unless it gets worse I am just gonna look for a good rebuild price in the meantime. This is long winded just to say I found the problem with much thanks to you trouble shooting it with me. Thanks for your expertise. I was at wits end and almost put a for sale sign on it. But with all the new little things I put into it, my ford ranger could last another 255,599 miles. Summer is coming and the AC is next. I appreciate you.

Hankhill3

 

Howdy, new here.

Not sure if this has been already said, I haven't read all the posts.

I've had issues with P0171 and 174 codes and they really are a pain to change. I had an 00 4.0 OHV with the 5spd and here are a few things I did and was recommended to me by local mechanics.
1. Check fuel pressure, it should be 60PSI+ If I remember correctly there is what looks like a tire stem coming off the fuel rail over the intake where you can check it. You can rent a kit from your local auto parts store to check (Will cost you no money overall assuming you return the rental tool). If it's bad fuel pressure, change the fuel pump [[b]THIS SOLVED IT FOR ME, BUT I DID TRY ALL THE OTHER POSSIBILITIES BEFORE I DID THIS SO TRY THIS FIRST TO GET IT OUT THE WAY]
2. Get some carb cleaner, have the engine running and spray it around the intake, vacuum hose and anywhere that has the potential of letting air in. When you spray over a spot that has a leak the engine will rev higher.
Will cost you about $5 give or take. If you find a leak, you'll need to plug it or replace the gasket if it's from an intake for example (or retorque the bolts if that's the issue)
3. O2 sensors can at times cause those codes if they are being lazy; the only real way to check as far as I know is through one of those fancy mechanics machines that plugs into the OBDII port and gives you all the info on the sensors and allows you to run tests. I have friends in the industry so it didn't cost me anything but it may cost ya $100 plus depending on the mechanic.
4. Exhaust leaks before the O2 sensor can cause it read that it's getting more air that what the MAF read. Could cause a lean running code.
5. Clean the MAF. Could get some specks of dirt on the fine wires in the MAF sensor that'll screw with it. Unplug it and see if it runs better in the computer's default modes, if it does, you may have a bad MAF.

Good luck!

 

Yeah your a little late in this game. Should have read all the post and saved yourself some typing time. smh.