Hey Rockledge,
Thanks for the post - I just finished checking out the EGR system here is what I found
- Key on Engine off - vref - 5.2vdc
- Key on Engine on - dpe signal 1.1vdc (I have the black case dpfe sensor.)
- When I place a vacuum on the EGR valve the voltage changes accordingly.
- The only problem I found was when I was monitoring the vacuum going into the EGR. The PCM is supposed to do a power on test where it places a vacuum on the EGR of about 3". I never saaw that. My vacuum at the EGR valve has remained near 0 every time I start the truck. At no time in the first 5 minutes do i see any vacuum greater than about 0.2".
- Can you describe the parameters that are required for the PCM to do the test? Each time I monitored the vacuum at this point the engine was warm and had only been shut off for a little while. Any ideas?
cscottyr

 

You can find those type of EGR parameters in the PDF file I posted a link to above:

http://www.motorcraftservice.com/vdi...f/obdsm99a.pdf

 

Well,
I'm waiting till Saturday - and I have a little cash to clean my fuel injectors - until then I have been wandering what could cause my problems. I will honestly be suprised if clean injectors will solve the problem.
During my last bout of troubleshooting wiht this vehicle - I had ran it without the EGR solenoid hooked up and had tried some other off the wall things. It never learned to run right after all my attempts of repair - so I disconnected the battery so it could get a fresh outlook and then I began to try and train it again. This thing is running very rough. On startup it will spit and sputter for a good 90 seconds before it wil respond to the throttle. After that it will run good then very poorly - then good then very poorly. You will be driving down the road and it will just runout of steam. Somehow the engine will stay running but you'll have to pull over to let the cars that want to go faster than 3 mph around you. After a while it will get goining again and eventually you will make it home. Does this sound like dirty fuel injectors? Even water doesn't act like this. When you have water in your gas you do get the crazy cycles but it will often start ok and not show up until you've shaken up the gas. And besides that I have put several tanks of gas through this since the problem started. Could the cam timing be off a tooth? - But why so sporatic? This truck has gotten past this issue twice. It will eventually choose an algorithm that will work. Then you only get the 0171and 74 errors - but it runs so rough until then. Maybe clean injectors will help but what else is going on that I'm missing? Is it a combination of #1 - The fuel pressure being on the low edge (57 pounds) #2 - the vacuum being on the low edge at idle (18"). #3 - the DPFE voltage being at 1.1vdc at idle instead of a high of 0.9vdc. Could it be the cam sensor isn't really pointing at #1TDC and is a little off causing part of the problem? Anybody out there have any huntches???

cscottyr

 

how about plugs and plug wires? you didn't mention anything on them. whens the last time you changed them? pull a couple and see what condition they are in. check to see if the wires are arcing.

 

Good point there.

As I mentioned, your fuel pressure seems fine for a FFV 3.0L.

The only other fuel-related thing I can think of aside from the injectors would be the cam sensor, which helps synchronize the firing of the injectors. However, usually a bad CMP sensor will throw its own code, or maybe result in a misfire (random type, most often) which would also throw a specific code.

Cylinder compression test results are always a nice thing to have in hand when you are troubleshooting an engine problem. You can borrow a compression tester from most parts stores. You've got nothing to lose, and it will give you a chance to examine the plugs and wires, as well.

 

Thanks for the posts - I'll pull them tonight and see what they look like! - Maybe clogged injecotrs are throwing the lean codes and the plugs are starting to fail.

cscottyr

 

By the way - thanks to all - especially Rockledge - for all the support given for this problem.
I bought the truck so I could get some work done on the house - and all I have time for is work on the truck. Actually I am sharing my time with several other vehicles. My Bonneville has developed a short ckt on the power rail. When you open or close a window -or turn the defroster on or etc. you will basically short power to ground and shut the car off- I also have an old acura integra that I've been changing out some front end parts to (so that I can sell it). Thankfully my motorcycle is running - or I wouldn't be doing the 40 mile commute to work very well. By the way its speedo cable just broke - and it really needs an oil change. My wifes car however is running OK - With my fortunes, I wont go any where near her car. And you should also know that I am a computer programmer and by definition am not really allowed to do anything mechanical! - Dont tell!
So to make a long story even longer - I really appreciate your help!
cscottyr

 

Rockledge,

Hey do you know anything about autolite ap764 -platinum - the ones in this truckare very wet - Are tehse sparks for the non-flex fuel truck?

cscottyr

 

Those are not the correct plug for the FFV application.

We've discussed the subject in the 3.0L Forum a few times, this has some of the latest info on the issue:

Correct Plugs for a FFV Ranger

 

Hey Rockledge,

Well I stuck autolite app103's in the vehicle - It seems to run a little better - but it still will occasionally nearly stall. My thought is that the plugs were very wet because of timing. Occassionally they will foul and cause the rough ride. Eventually the computer will really lean out the mixture and they will not foul anymore - but I will get the lean mixture codes afore mentioned. That is my hypothesis. What do you think? I need to borrow a timing light and get a look at where it sits. To remind you - I did pull off the cam sensor and inspect it - looked very clean. Also the assembly seemed to be tight and I dont think it is messed up. I do believe it could be mispositioned causing the intake valves to be opened to late at the end of the spark and therefore not getting a good burn. Let me know if you think I'm nuts!
cscottyr

 

Hey guys - how much do you think I'd advance the timing if I moved the cam timing assy ahead one gear? Am I making any sense? Or am I going about it the wrong way?

cscottyr

 

what condition were the plug wires in? I dont believe you said anything about those. How old are they? any arcing? examine them carefully. a damaged wire will cause a lot of headaches like this also.

 

The plugs were not old - they were gapped correctly and were burning very rich. They were very black with oil. 4 out of 6 looked worse than the other 2. Also I dont see any evidence of bad rings coming out of my tailpipe.
cscottyr

 

After doing a little reading I am going to see if I have a voltage signal on both the ckp sensor and the cmp sensor. I suppose its possible that the computer is loosing those readings on occasion and misunderstanding when to spark and to fire the fuel injectors (how long also). If that were happening - I believe I would be seeing a computer MIL. But I will check to be on the safe side anyhow.

Since I found many wet plugs that rules out a single module on the coil pack - that means at least 2 of the 3 coils need to be failing- (probably not) I will check out their resistance tonight also. When the truck fails - It feels as if its missing on at least 2 cylinders - I've fealt 1 cyl missing on a 6 cyl before. This is not like that - It feels more like a 1 cyl missing on a 4. Neverthless I will also carefully inspect the wires. Last night I noticed the base of the coil module was rusted - I cleaned it up.

After all is said I am however, still leaning towards a retarded timing problem. Remember this truck didn't start acting up this way after I drove it for a while - This truck has been acting up since I purchased it. The only time it has been better has been after the computer really started cutting back the fuel. This caused the 0171 and 0174 errors. During this condition of low fuel I probably stopped fouling the sparks. After I have disconnected the battery and reset the computer memory - it throws 1131 and 1151 codes - More akin to a sensor trying to correct for an overly rich problem. If the plugs run long enough and well enough they finally clean up as the computer leans out the fuel - and the truck appears to run better since the fouling is gone. However it pings excessively and has low power in this condition. If someone had changed out the cmp - prior to my purchasing the truck maybe they didnt set it at 10atdc. WHo knows? - Any ideas??

cscottyr

 

how many miles are on the plug WIRES. bad wires cause cylinder misfire.