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Need some INTERPRETATION with these OBD I CODES

I

iskoos

CEG'er
Joined
May 23, 2008
Messages
245
Location
Orlando, FL
95 Ford Contour GL - 4cyl Automatic @ 170k

I have been trying to fix my erratic idle problem since March with no luck so far. The car idles so bad and if the engine is cold it will shut off within 2-3 seconds of firing up.
I have done so many things so far but none helped.
So far I have been retrieving the codes through counting CEL on the dash and recently I bought a scan tool and I was able to do a complete scan. After using the scan tool (AutoXray 5000), I retrieved the same KOEO (Key On Engine Off) codes as 335, 181, and 543. Scanner says 335 is on demand code and 181 and 543 are memory codes.
Then for the first time I was able to do KOER (Key On Engine Running) test. It was pretty cool to see this on a 13 year-old car.
Anyways, I got two different codes I haven't seen before: 172 and 336

So in short this is what I have:

KOEO Codes:
335 (On Demand meaning detected during the test)
181 (Memory)
543 (Memory)

KOER Codes: (Both must detected during the actual test)
172
336

Please do not look up and give me the textbook definition of these codes only. I already know them. We know that sometimes a specific code(s) may point a component that is not necessarily malfunctioning. I know some of the above codes point out the O2 sensor but it is new. I replaced it in February and I probably put only 500-600 miles on it before I got this problem.
I am getting 335 and it is known as DPFE sensor. That's replaced in February as well and just to make sure I replaced it again in the past summer but it didn't help.
The car sputters really bad at idle. When accelerate, there is no problem. The power is there and it is smooth. I am sure I can drive hundreds of miles on a highway as long as I don't need to stop. But as soon as I remove my foot from the accelerator and let the rpm goes down, engine starts sputtering badly and most of the time it will quit.
IAC valve??? Do not hold your breath, that was the second thing I replaced. I first cleaned it, didn't help and then bought a new one. No luck. It is not it.
Replaced PCV valve, cleaned oil seperator, replaced spark plugs, spark plug wires, ignition coil, fuel filter. I even tried new MAF sensor, nothing changed.
Also checked the EVR solenoid, charcoal canister, purge solenoid, cleaned TB, EGR passages etc. etc.

I did alot of work with no success. Friends are telling me to get rid of this car but I don't want to let her go. I have owned her for almost 10 years.

There are some really knowledgable guys among you, I would appreciate if you could share your thoughts on this matter.

Thanks in advance
 
based on the codes and the sputtering at idle, it sounds like its running lean. based on the 543 code, check the fuel pump relay and the fuel pump itself. also, check for any vacuum leaks as well. since its 13 years old i wouldnt doubt if some of the vacuum lines have become brittle and cracked.
 
Defeat the EGR, block it, plug it, do what you must to guarantee (1) that valve is shut and (2) DPFE can't turn it on. Forget the code, you are trying to weed out variables to get car to idle. You can pick back up on EGR trouble later. No EGR will NOT effect normal running engine. Good O2 sensor will go both above and below .5 volt pretty much evenly if not and you know sensor good then accept what it says, less than .5 is lean. Meaning start looking for the leak instead of expecting a new part to fix it. The uneven switching can be at idle and then go to even switching above idle. That can show vacuum leak, as the percentage of leaked air drops off as total amount changes with demand rpm. You didn't need the scanner to do those engine off and running tests, I did them all on '94 models and pulled all codes with just a check engine light. You just need to know the regimen. Anybody done a compression test? You'll feel real silly if basic motor being bad made you chase yourself around in circles. If fuel pump rotor wore out can affect idle and not higher up even though most of us are taught that bad fuel pump shows up on higher demand. Worn impeller lets fuel sideslip past it until demand lets enough flow to keep it going.
 
Thanks guys!.. I will answer in the same order...

striker2,
I was told that it could be a vacuum leak. Yes, the car it old. I inspected all the vacuum lines behind the intake and found only one brittle line and replaced it. It was the one coming from purge solenoid. It was brittle but NOT cracked or torn. Even if it was, it wouldn't have cause this kind of problem. Obviously replacing it did NOT help. The only other possible vacuum leak could be from intake manifold gasket and I wasn't able to check that. So it could still be a vacuum leak I just don't have much to do on that.
The fuel pump runs. I can hear it for about 2 seconds when I turn the key on. I have yet to test the pump pressure. I found a pressure gauge but couldn't figure out how to do the test yet. Hopefully soon.
If the pump is running, would you still suspect the pump relay? Could the relay be bad and the fuel pump still running? I kind of do not think so but I might be wrong.

amc49,
You pointed out so many important things thank you!.. Almost everything you said spot on. A footnote before I get into main issue. I didn't buy the scanner to solve this problem only. I have been looking to get one for a long time and instead of buying a simple OBDII scanner, I wanted to buy one that can do both OBD I and OBD II. And AutoXray 5000 was a good deal for me. Like I said I did retrieve the KOEO codes by reading CEL but I didn't know one could also do KOER test with the same method. Even if I knew, this would not change my mind on buying a diagnostic tool. I was going to get it anyways.
You pointed out so many valuable things. I will only focus on ONE of them: the EGR valve. It is like you read my mind. I have been wanting to test to see if the EGR valve is sticking open (when it shouldn't) at idle for a long time. I have spent hours in the engine compartment and with all my knowledge, I only know TWO ways of doing this on 4cyl Zetec Engine:

1) By removing the EGR tube from exhaust manifold and caping it. I also need to cover the hole on the exhaust manifold at the same time or I would probably burn somethingn with the hot exhaust gasses.
2) Simple removing and replacing the EGR valve.

Other than these two options, I do NOT know any other way to block the EGR flow into intake.
If I knew EGR valve is definitely the culprit, I wouldn't sleep all night and replace it. But if I find out that it wasn't the cause after spending hours and replacing it, I would be very disappointed.

The sputtering at idle is excatly the same when you do the suck test on EGR valve. It is same type of sputtering. As if EGR valve never gets closed. So it is very very likely that EGR valve might be sticking open or doesn't close properly. And if it is open(or halp open) I know that this is not caused by DPFE or EVR solenoid. I checked the vacuum line going from solenoid to EGR valve end there was no suction on it at idle. So this tells me that EVR solenoid does its job. I even left the vacuum line disconnected to make sure nothing is opening the GR valve. Nothing changed.

Too darn bad that there is no staright forward way to block EGR flow into intake...

Do you know another way other than the TWO I wrote above?
I feel that I must defeat the EGR excatly the way you said in your first line.
 
Haven't pulled the EGR valve off the Contour but if similar to Focus, I did one last week. Valve attached with a big nut to supply tube at bottom and bolts to intake entry with 2 screws at top. Pull valve and make some kind of block off plate, I used .007 thick aluminum out of a printing plate (I am a printer), any thin sheet metal will do. Make a copy of the gasket shape but without the big hole in middle. Bolt all back together with the blockoff plate next to gasket. EGR now blocked off.
 
Do not remember exactly before looking at it and for that I need to remove some stuff from the engine compartment. But if I am not mistaken I already tried that route and it didn't seem possible to me. I will look at it again tomorrow and let you know.
 
I found a vacum pump/guage to be an easy way to look for vacum leaks just unhook the vacum lines from the engine and hook the vacum tester up to it try and pum up a vacum if it leaks down you have found your leak you can also use it to operate your egr valve/make sure it is working..... if all you vacum accesories are holding vacum start looking for leaks in the intake track after the Mass Air Flow sensor..... have you checked your sparkplug wires/firing order? did the idle problem happen after you did something to the engine?

good luck.....these kind of problems can be frustrating.... I've found that sometimes it is something that you belive to be fine that you already checked or think you already checked....
 
That method will not detect the leaks that occur right where line plugs into motor as you have disconnected it. That's where most leaks happen, right where plugged into engine. Hottest location with most vibration.
 
amc49

amc49

After couple days of Xmas break, I worked on my Ford today for several hours. I wanted to test the fuel pressure but wasn't able to due to different type fitting on friend's pressure gauge. I am trying to get the correct one...
Meanwhile I worked on the famous EGR VALVE!.. amc49, I tried your method, and it worked. I was able to seperate the outgoing tube (to intkae) and pull the gasket out. I had nothing to block the tube, the only metal I had was way too tick to insert. So I did use aluminum foil instead. I removed the gasket and wrapped it with aluminum foil. I wrapped enough(about 10 layers) and then put it back with only two holes so the bolts can go in. I put everything back and started the car. Unfortunately:( didn't fix the problem. I can say the car ran just a notch better at idle but the sputtering problem was there with no doubt!... So I warmed up the engine and test drove it in my neighborhood. Just like it was before, car drives fine so long as you keep your foot on the gas pedal. When you remove it and let the rpm starts going down when you approach to stop signs, that sputter comes back. If I slow down easily, it will hang on and keep running but if I hammer the brakes and stop immediately, it will quit...

While driving, I got the CEL again. then I hooked up my AutoXray scanner to see if there is any new codes. Yes there was one

332: Insufficient EGR flow...

Well I would be surprized if I didn't get this code. I blocked the EGR flow and I got this code. This tels me that my EGR valve is okay. There is NO problem with it. I also did the suck test before and it came out the way it should have. With this, I am ruling out the EGR valve that I have been suspecting for a long time...
Good thing is that I don't need to spend money to buy and replace my EGR valve. The bad thing is I am running out of things to do:(((

I will check the fuel pump pressure soon but I have the feeling that it won't be the problem either...

The latest scan still gives me the same codes and here is the code explanations exactly the way they show on the screen:

335: Exhaust pressure transducer sensor voltage out of range during KOEO
181: Fuel system at rich adaptive limit at part throttle. System lean bank 1
543: Fuel pump secondary circuit failure battery to control module
172: Lack of heated Oxygen sensor switches indicates lean bank 1
336: Exhaust pressure high. Exhaust pressure transducer circuit voltage higher than expected

On top of these I get 332 today and as I stated above that was due to me blocking EGR flow to intake...

So far this is what I know...
It can't be the oxygen sensor for 2 resons:
1)The car shows the symtomps as soon as I start it up. Oxygen sesnor doesn't start working till it gets to certain temperature (closed loop) In this case, the car does better when it is fully warmed up.
2)I had bad O2 sensors before and the symtomps were lot different. Car would miss at crusing speed after engine warmed up. Never at idle... And O2 sensor was replaced this year in February...

It can't be the DPFE sensor or EVR soleniod either. Again for 2 reasons:
1)Simple I replaced bith and nothing changed
2)DPFE sensor and solenoid opens the EGR valve when PCM sends the command. EGR valve spring loaded closed. So no EGR unless PCM tells EVR solenoid to apply vacuum to open it. And engine doesn't need EGR to run properly. Only too much EGR flow(especially in idle) causes the engine to run poorly. And I blocked the EGR flow. So all this tells me that DPFE, EVR solenoid, and EGR valve can NOT be the problem...

My spark plugs are brand new... I replaced the plug wires and coil pack for the heck of it. Didn't fix it!...

Put a new MAF sensor... Didn't fix it!..

Put a new fuel filter... Nope not it...

New PCV valve, cleaned the oil seperator... Nothing...

I did inspect the intake booths and found no cracks...

Couldn't check the fuel pressure but will do in couple days. Could it be the fuel pump? Does a fuel pump cause hesitation at idle but not at cruise speeds???? Shoul I check pum Relay as someone recommended? I am Clueless...

I did my best to loctae any vacuum leak but couldn't find. I do have a vacuum pump. If I unhook the vacuum lines and use vacuum pump, would it really help me locate any vacuum leak?

I last clue if this helps. Accelerator is kind of sensitive at low end. When the engine starts sputtering, if I press on it very little, it doesn nothing; rpm doesn't go up at all. Then I press more and more and all of a sudden rpm goes up way too much. I let my leg go off, rpm stays high for a few seconds and then drops really fast where the egine starts sputtering...
Does this tell you anything???

I know this become a long answer but I wanted to give as much info as I could...
 
Another Question

Another Question

There is DCL Data scan on this scanner unit I have. Does it provide any help if I use it? I don't know what that is. never heard before...
 
Have you ever run the compression? Real low compression shows up as crappy idle first, then sudden dying when throttle let go or brakes hit. Power will be off, but that can be gradual enough so that many people think motor still has plenty of power when it really doesn't. Still sounds like a vacuum leak first guess, O2 sensors telling you that. It can be damn hard to find them sometimes. In the data scan portion you mention see if you can call up the O2 sensor (high one or bank 1) and watch it while running. That scanner should be able to do it, I think, mine much cheaper and it will. O2 sensor should be switching up and down past .5 volt if engine runs right, say from .1 to .9 or so. When vacuum leak shows it will tend to stay low or below .5. If leak, should be worse at idle, when you slow rev engine up, it may start to cross over .5 and switch then. Idle fuel trim is not much, a leak will cause PCM to use it all and then still not enough, however higher speeds there will be enough fuel usually to be able to adjust. Sounds like EGR not it. Notice you did not screw with any of the EGR parts to do that, you went straight to valve itself and by that weeded out all the other EGR issues it could have been. Attempt same treatment for vacuum leak. I start by pulling every hose I find on intake and plugging the intake hole left. Most of those hoses not necessary just to get motor to idle. You've mentioned PCV, what about where the other end of that system enters intake, block it. That spot a common Focus zetec leak problem. You don't need PCV air just for testing, one more variable out of the way. Idle speed will just drop a little with it temporarily blocked. Power brake has a vac line to it, block it in the driveway, just don't drive car like that (NO BRAKES!!!). Don't need heater or fuel evap vacuum lines either, in short start blocking off EVERY vacuum line you find, if vacuum leak, good chance you may find it, but you gotta check THEM ALL. If you're diligent then only thing left is intake cracked or intake to head gasket, maybe fuel injector o-ring? I'd get into the scanner first, if you can read the running output of that O2 will tell you where to go. Also know this, when several codes show up, list them IN ORDER PCM SPITS THEM OUT. You service them in same order as they appear from PCM. Sometimes one thing going wrong will set other codes. If you started on last one first, you could be fixing something that has nothing wrong with it.
 
Just looked again at your last post. Not trying to be a butthead, but pull out scanner manual and READ IT. That information ain't just gonna auto-inject itself into your brain. You have a need for active on the run scanning RIGHT NOW. Make that freaking tool pay for itself!
 
amc49 said:
Just looked again at your last post. Not trying to be a butthead, but pull out scanner manual and READ IT. That information ain't just gonna auto-inject itself into your brain. You have a need for active on the run scanning RIGHT NOW. Make that freaking tool pay for itself!
Click to expand...

Thanks amc:)

It was fun to read your reply. I am glad someone is paying close attention.
I will start with O2 sensor reading. I did use this scanner to read O2 sensor on OBD II car. So my only concern would be this car is 95 (OBD I). I hope that it is possible to read live O2 data on OBD I.
If it is, consider it done.
I will keep you updated, give me a day to figure out this.
Also I will read that manual more:)))
 
amc49 Hear me OUT!...

amc49 Hear me OUT!...

amc, you are like reading this car from where you are...

I read the darn instruction manual and the DCL scan was indeed a live streaming data. I just ran a test in my garage with my scanner AutoXray 5000. I warmed up the engine first. It was darn difficult to do that since engine tends to quit everytime I let go off the gas. Anyways, I called the DCL data and things started popping up on the screen. I went for the O2 sensor data first. By the way, my car is year 95 - OBD I compliance. So I only have one O2 sensor that is pre-cat. So don't you think that I read the down stream O2 sensor. I don't have it.
Anyways, I found the O2 voltage and it was showing 0.09volts. I started watching it. And at idle, it was changing between 0.09 and 0.10 volts only!...
When I reved up the engine to 1500rpm level, it started seeing 0.7 - 0.8 volts but as soon as I let it go back to idle, it was staying at 0.09volts.
Just to make sure I if I was on closed loop, I looked for it and yeas I was!.. The scanner was showing me that I was on closed loop.
Man, this little tool showed so many live data on its screen that a person who knows how to read it can gather lots of valuable info without getting under the hood.
I ran the car about 10 minutes and after that I shut it off. Here is the data at the time I shut off the engine...

01 Engine Speed: 852 RPM (seems a bit high for idle to me)
02 Spark Advance: 30.7 Degree
03 Intake Air Temp: 3.1 Volts
04 Engine Coolant Temp 152.0 F
05 EGR Feedback: 0.9 Volts
06 Throttle Position: 0.9 Volts
07 Vehicle Power: 13.4 Volts
08 Injector PW: 4.2 ms
09 EGR Vacuum Regl: 0.0%
10 Idle Air Control: 27.9%
11 Vehicle Speed Sensor: 0 MPH (obviously)
12 Oxygen Sensor: 0.09 Volts
13 Brake (BOO): Off
14 Park/Neutral: Yes
15 Low Speed Fan: Off
16 High Speed Fan: Off
17 WOT A/C Cut-Off: Yes
18 Loop Status: Closed
19 Power Steering PSI: No High

So this was the all 19-point data. I am very surprized to see all this from a 1995 car to be honest.

Looks like it will come down to your guess vacuum leak.
So you would recommend pulling the vacuum hoses one by one while the engine is running at this stage?

Thanks
 
You can try spraying carb cleaner on the vacuum hoses while the engine is idling. The engine will sputter when you spray in the area of the vaccuum leak.
 
Yeah, you can do that, don't get too heavy with it around exhaust, fire hazard. The engine at idle must cross .5 volt both ways to show idle mixture being controlled. Vacuum leak is pretty much a fixed amount, shows at idle the most because it is a higher relative percentage of total fuel mixture amount. Once engine pulls away from idle, there is enough fuel injected to mostly if not completely correct for the leak. I see numbers you have there but should actually be screens you can call up with graphs on them to show the actual cross over occurring. Say a horizontal line down middle of screen for .5 volt, with a constantly moving traced point in space that swings both above and below it. Clearly shows it. Many of those outputs will use that trace screen, it's invaluable. Dig deeper in the software and see if you can find it. You got EGR output states too, someone could drive car around and pull live EGR info out of thin air. That scanner better than mine, my brother has that brand, with deeper problems I dig him up to use his.
 
Well I heard a lot about it but I am really not keen on using a spray method in this case. The engine is sputtering enough the way it is already. I don't think making it sputter more will help me much to diagnose the problem.
When cold, there is no way it will hold idle. Once it is fully warm, then it will idle on its own but the idle will be erratic. It will idle okay for 5-10 sec and then all of a sudden, the rpm will dip and if gas is not applied right then, it will most likely quit.
I would like to go with unpluging vacuum hoses one-by-one method but now this bad idling makes me think how I would do it without getting a help from someone!.. I mean I may need someone to keep the engine running while I am pulling the vacuum hoses one-by-one...

amc, can you give some further instruction on this method? For example, most of the vacuum lines are behind the intake and to be able to reach there, I need to remove air intake plenum chamber. The plastic chamber sits on throttle body. But then can I run the engine with the TB open to atmosphere????
If not, then there will be a lot of work for me because I will remove the plenum chamber to pull the vacuum hoses and then put it back to start the car and this will go on and on for each vacuum hose!..
What is the best way to do this test? I would like to spend some time on it tomorrow....

P.S. amc, there is NO graph on this tool. I checked the whole manual and it doesn't say anywhere that this display has graphic ability. It would be nice if it had but, it still gives me lot more than I need. Live data is a great function.
 
tracking down the vacuum leak...

tracking down the vacuum leak...

Could someone please enlighten me a bit more on how to track down a vacuum leak by pulling vacuum lines?

I imagine, I will pull them one by one and run the engine to see if the dile gets better but a few things confuming me.
Like can I RUN the engine with airbox assembly off the throttle? It doesn't seem logical as I think about it. MAF won't be measuring the air for example... Don't know???
I am asking this becasue airbox assembly(planum chamber etc.) needs to be removed to reach those vacuum lines and if I am going to put everything back after pulling each vacuum line, it will be a real PITA to do this test...

I don't want to do this twice. So I appreciate if you share what you know...

Thanks
 
Leave everything like airbox and TB attached, indeed car will not run without. Pulling the lines sucks, there is no easy way, you just gotta search them down and separate or spray like the man says. You get to reach around back of engine where no room and chance of breaking off old plastic hose barbs is great. I have cobbled up a collection of old pieces of different sized vacuum hose plugged at one end so I can sub that in place of a line to block it. Harder now as many attachment points do not lend themselves to that because of the new quick disconnect methods used to join parts.You can always put something under throttle stop to increase the idle temporarily while checking. One could use a propane torch unlit, turned low, engine speed will increase when you find the leak, but that's dangerous. Could result in fire. Trace where the PCV goes to finally enter intake and block that entry off, that's usually the first one I do. Then there's vacuum to the evap stuff, heater controls, power brake assembly. Probably others, too, model dependent. Then intake manifold seals to head and around imjector o-rings. Any other leak after MAF will cause trouble. You really should check out the idea of compression check also. You have no idea how many people work forever on car with no results only to find the basic engine was not going to run anyway because no/low compression. That results in really uneven crap idle that tries to die. Has the throttle body ever been cleaned around the blade? That area right where butterfly rests at full close needs to be clean as well as edges of blade itself. The supersmall airleak there is critical to work properly within the range of the idle air solenoid. Don't worry about the crap inside manifold itself, harmless unless it blocks the solenoid air pathway. You may be able to look at your injector pulses with that scanner, may tell you if one is off somehow or weak.
 
Update

Update

Well the case is still going on but figured I need to update this post.

Before digging into vacuum leak mess, there was two more tests that I wanted to do: Fuel Pressure and Cylinder Compression tests...

Well I did both:

Fuel Pressure:

@ Idle FPR vacuum hose connected = 30 psi
@ Idle FPR vacuum hose disconnected = 40 psi
Hold pressure = 30 psi

All these results are well withing the specs. So Fuel system working alright...

Cylinder Compression:

Did the test twice for Cylinder # 1 thru #4 and each time the gauge read 150 psi almost dead on. I would say the difference between cylinders were no more than -/+1 psi.

So with these two items, I did everythign I could do. Now it looks like this is a vacuum leak issue as amc49 guessed and I will have to find it.

It will be a darn difficult thing to do:(
 
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