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While my 1997 Ranger is at the Ford dealer for this clutch thing I asked them to diagnose the engine light. My reader had a few codes showing things related to emissions. I replaced some hose sections that looked iffy and a plastic purge unit (T connection at the top of it) near the battery but the light came back.
Anyway, the tech says I need some sort of "hose kit" for $500 plus something else and an air box that may no longer be available from Ford.
The kid that I bought this truck from for $1500 (big mistake... I can see that now) had removed the OEM air filter and installed this cone shaped one like you see on motorcycles, only larger. He had it tied off with wires at the end of the black air intake shroud.
Do you think this is causing part of the problem?
Any idea what this hose kit is that costs $500?
The codes I got last year when I checked:
P0401: EGR system flow is insufficient
P0171 & P0174: System too lean bank 1 & 2
P1443: Evaporative system purge control
Without having any readings from a scan tool for Short term and long term fuel trims, My first guess would be the Mass Airflow Sensor causing the the codes for P0171& P0174. The hose kit may be needed to hold the sensor. The code P0401 EGR insufficient flow normally is the hose tubes deteriorating going fromt the drivers side manifold tube up to the DPFE sensor. You can replace them with fuel line hose. As for the last code that could be more tricky to help with over the internet if you dont have the truck.
Without having any readings from a scan tool for Short term and long term fuel trims, My first guess would be the Mass Airflow Sensor causing the the codes for P0171& P0174. The hose kit may be needed to hold the sensor.
They (CRC) make a spray cleaner for this. Worth a try to use it, first?
The code P0401 EGR insufficient flow normally is the hose tubes deteriorating going fromt the drivers side manifold tube up to the DPFE sensor. You can replace them with fuel line hose.
Seems like I replaced all these last year if they are those short sections of hose up to and away from that plastic device that hangs off near the battery. Not sure now if maybe that code went away. Will get more complete data from my reader when I get the truck back.
You did not mention if the non-standard air filter had anything to do with this. Too lean would mean too much air in to the mix. Perhaps this cone filter is forcing/letting way too much air in?
I run a filter like you are describing on my 94. It was designed for the 97 but fit anyhow. Most of all you probably have a bad MAF at a minimum. I have had to replace these before, with and without the factory airbox! As I recommended before find a good independent repair shop and have them take care of issues. Dealers will charge to 'look at' but do little as you said in another post about the diagnosis was based on your description. I would be leary of work by this dealer as it may seem to be that $500 is their baseline repair quote.
Good idea to have posted the trouble code Numbers you have.
If the cone air filter is an oiled foam, or gauze type air filter & maybe if it was over oiled, may have by now passed enough dirt & oil to have fouled the MAF sensor heated wire enough to have corrupted its PID to the computer about true airflow into the engine. That could have the engine computer mess up fuel injector squirt time, thus the lean both banks code.
If the O2 sensors have more than 75K miles on them, their switching speed & voltage range feedback to the computer could be slow & not broad enough & cause the computer to mess up fuel trim, so even though you haven't posted a specific code for O2 sensors, they belong on your suspect list for now.
The OEM filter air box being removed takes away the factory cold air intake, letting hot under hood air into the engine, which can cause driveability problems with low vapor pressure winter fuel on a warm day. Lots of good reasons to reinstall the factory system, so inquire if the previous owner still has the old air box, or visit your local salvage yard for a donor.
The EGR code is usually associated with a faulty DPFE sensor, or corrupt hoses to it, if the engine uses a good bit of oil, maybe a clogged up exhaust gas feedback port, that's located below the EGR vlave, to which the DPFE sensor high temp hose connects & if its stopped up, check the high temp hose to see if its clogged up with carbon.
Or maybe the EGR vacuum control valve diaphragm, or hose to it is leaking vacuum & thus not properly controlling the EGR valve, but you've not posted a trouble code for it.
Lastly, if the EGR valve itself is rusty & falling apart, it'll belong on your suspect list, otherwise its robust & not usually the cause of EGR system woes, again unless the vehicle is using a lot of oil, then carbon deposits could need cleaning.
On the evap system code, it's usually the vacuum switching valve itself that causes that problem, sometimes the hoses are dryrotted & leaking vacuum, but shouldn't cost $500 worth of repairs. Think I'd just ask for a quote & think about doing the repairs myself, if your ok with turning your own wrenches, or have a friend that could advise you.
Some thoughts for pondering, let us know how it goes.
Just picked up the truck. Here is what the service tech said on the sheet...
Needs an air box for PO 171, PO 174.
Needs VAC lines repaired for PO 401
Needs a hose and sensor assy. for P1443
Vacuum hose kit $518.00 & EGR repair @ $100.00
Air box not avail. Need to source a used one.
Is that the DPFE sensor he is referring to?
BTW: It uses really no oil. I never seem to have to add any and it stays right on the mark. Still, I will get some cleaner for the MAF sensor. Can't hurt.
No, the DPFE sensor is for the EGR system, he's talking about a vapor recovery sensor & hose for the P1443 vapor recovery system code.
My code definition shows the P1443 code to be for the vacuum system of the vapor recovery purge control valve or solenoid.
If its faulty & stuck open, or a hose is dry rotted & leaking vacuum, that vacuum leak is down stream of & not monitored by the MAF sensor, so it could be figuring in on the lean both banks lean codes.
We're supposed to work & put right the lowest code numbers first, then work our way up the list to the highest code numbers last.
So work the EGR trouble code first, as if it has vacuum leaks in its control system, they too are down stream of the MAF sensor & can mess up fuel trim, so could figure in on the lean both cyl banks codes.
So inspect the EGR system vacuum hoses condition & their fit, as soft loose fitting, or hard, cracked, dry rotted, loose fitting hoses can cause vacuum leaks & EGR system control problems & fuel trim problems.
Then work the vapor recovery system problem, looking for the same kinds of problems with its hoses & vacuum lines.
Check the operation of the vapor recovery solenoid with the engine cold. At KOEO before you crank the engine for a start, you should feel it click open, so intake vacuum can suck stored gas fumes out of the charcoal canister to purge it. These gas fumes are highly flammable & easy to ignite, so they help speed up cold engine starts. So if its cold starts have been stubborn, slow, suspect the purge control valve, its solenoid, wires, electrical connector, or opening voltage is missing.
If you have been smelling raw gas fumes, suspect a bad leaking vapor recovery hose all the way from the charcoal canister to purge control valve/solenoid assy, through it to the intake manifold fitting. If its bad & leaking gas fumes that you can smell, it'll also leak vacuum & mess with fuel trim. All a vicious circle, so get under hood & have a look for loose, dry rotted, cracked vacuum lines or vapor recovery lines & let us know what you find.
Probably not a bad idea to clean the MAF sensor, but do it after replacing the air box with an OEM air filter, then disconnect the battery B- cable & remove the MAF sensor. Let it come to room temp before spraying with CRC, or Valvolene MAF spray cleaner, being careful not to touch the wire sensor with the nozzle or your fingers. Keep it squeaky clean upon reinstallation & make sure you let it dry before starting the engine.
Disconnecting the battery will wipe the KAM & the corrupt fuel trim tables, so the computer can begin to build new tables with the cleaned MAF sensor inputs & it wipes the cold & warm idle strategy, so perform the idle relearn routine Ford Truck Enthusiasts Forums - View Single Post - high idle problem to prevent idle, or driveability problems.
These replies are appreciated. Appears I have my work cut out for me. As soon as the weather gets a bit better and I can get in to this I will start... as was stated... with the lowest code #'s and work my way up.
Here is my filter the way it came on this truck. Does it look at all proper or should I try to find a used OEM air box?
I completely agree with the statemants that Paw Paw made. Now whoever did that to the filter was some kind of out there. But good news is you have time to make the proper repairs. Hang in there and keep us posted on the progress. Lots of help and knowledge on the ranger board. I think Paw Paw can build one in his sleep and I work on a fleet of about 70 of them. I am sure we can help out when ever needed. I will check my junk pile to see if I have one of the round filter ends if so I will let you know.
I'm back to working on this code issue again. Have until end of July or I lose the registration on my truck so need to get cracking.
Update: I replaced the fuel filter this weekend. That seems to have cleared codes P0171 & P0174: System too lean bank 1 & 2. At least they have not returned in the last 40+ miles.
Was able to source the OEM air cleaner assembly from a salvage yard in the Midwest. So the entire original air cleaner is now there. It came with a "still good" K&N oiled conical air filter so, after air blowing it from the inside out, I have left it in there. Seems to allow for better air flow than the auto store version that is not cone shaped in the front.
The MAF sensor is located in the second stage of this air cleaner assembly. It was removed and carefully cleaned with MAF cleaner, dried and then reinstalled.
That leaves two codes. P0401: EGR system flow is insufficient & P1443: Evaporative system purge control
There was a video on Youtube that showed how to test the EGR valve. Basically, you connect a hand vacuum pump to it. Run the truck in idle and pump a bit. If the valve is working and there is no port blockage the engine should stumble or even stall. Did that and that's what happened. I assume that valve is good... for now.
Checking around in that same area I found a 90% open crack in the small vacuum line going to the EGR solenoid. See the red tube in this pic.
I was able to repair this easy enough. Checking around did not find any other similar cases of line cracks.
Cleared the codes and off I went. After 20 miles both codes are back.
So next I will remove that EGR solenoid and bench test it to see if it works.
Other than that, is there a way to test the vacuum to that solenoid to see if it is supplying enough negative pressure to work the ERG?
Question: I'm only using the "clear codes" button on my reader. Should I be, as PawPaw suggested, disconnecting the battery to clear the computer of past history?
Done it all and still it is there. Here's where I am now:
1) checked EGR valve by appling vacuum from hand pump. If doing that causes engine to run rough it indicates valve is OK. Did that and it passed.
2) checked DPFE sensor by checking voltages. Middle pin ground, bottom pin 5v supply and top pin signal output. Measured at rest, top pin around 1 volt. As vacuum applied to smaller port (hose in mouth) voltage rises steadily to 5v. Indicates sensor good.
3) checked vacuum system. Checked all vacuum connections and hoses. Did find large crack in hose to EGR solenoid (see post above). Repaired and still same code came back. Vacuum pressure off intake manifold is -20hg and steady at idle. Vacuum pressure at hose to ERG solenoid also -20. NOTE: thinking this solenoid was bad (it was not) I bought a new one from Ford dealer so that is now out of the equation.
4) purchased NOS air cleaner system not on vehicle when I got it. Air intake now factory stock all the way around.
5) cleaned MAF sensor with recommended spray clearer. Did not seem that dirty to begin with. I have not tested the MAF sensor but according to this article it would not give the codes I'm still getting.
All this and still that darn code comes back. The only thing I can say is the EGR is pretty gnarly looking. Lots of corrosion on it and the fittings to and from it. Vehicle has well over 200,000 miles and has had numerous owners prior to my getting it. Last kid who had it before me was a jerk and took no care of it at all. That said, this part "seems" to test good according to what I've read on how to check it.
What type of exhaust system do you have? Has it been modified? I wonder if that previous owner gutted the cat? This is why I ask;
From what I understand, the DPFE sensor is a very sensitive pressure sensor. It's hooked to the pipe that feeds exhaust to the EGR valve. That's why it has a special silicone high temp hose hooked to it, there is actually exhaust gas going to this sensor.
There is supposed to be some backpressure in the exhaust. We all know this is a bad thing, but it's the way it works. As the engine runs, there is some backpressure that builds up in the engine area exhaust, and this means also in the EGR exhaust gas metal supply pipe. The DPFE sensor reads this slight pressure in the exhaust. You also need this slight pressure to create flow into the EGR valve.
So when you are driving down the road, the DPFE is reading this exhaust pressure. Then the computer decides the engine is warmed up, we are driving down the road, it's time for some EGR. So it tells the EGR vacuum valve to open a little bit to put vacuum to the valve. The EGR valve should open a little bit. When it opens, this lowers the pressure in the exhaust supply pipe, and the DPFE sees this pressure drop and sends the signal back to the computer. This is verification to the computer that the EGR really did open, and it uses this sensor for feedback as to how to control the valve.
In your link above on how to test this stuff, they told you to measure the voltage coming out of the DPFE with the engine off and the engine running. This will verify the sensor is working and is actually seeing some backpressure. If you feel confident that the sensor is good, that does not mean that you may not have exhaust pressure at the sensor with the engine running, either from a clogged EGR supply pipe or a exhaust system that flows too free and is not shoving any exhaust back up into the EGR supply pipe.
Spent better part of Saturday chasing down this EGR code. Leaving no stone unturned, as they say, I mounted my DVM on the dash board connected to the DFPE sensor...
along with a vacuum gauge connected to the EGR valve input via a T connection from the EGR solenoid.
Then I took the truck for a few rides to see what I'd get. What I got was what seemed to me to be working components all the way around. The DPFE at idle was 1.00 volts... as it should be. Driving at 35mph with acceleration gave me 1.20 volts. Driving 55 and accelerating to 70 the voltage climbed from 1.3 to around 2. As soon as I took my foot off the gas it dropped to 1.00. Again, this is what should happen.
Next came the vacuum test. At idle it read 0hg. Accelerating from stop it would steadily climb to -5hg... the correct pressure for a working unit. Driving around 55mph with moderate acceleration it would hover at -4 to -5hg. All this is correct according to what I've read.
My tests with manually applying vacuum with the truck in idle found any amount of negative pressure would cause the value to open and the truck to run rough. Clearly, then, these values indicated exhaust gas was getting back to the intake while driving.
