CEL and Rough Idle Brain Teaser

ernestrulezd00d · #1 08-15-2011, 02:57 PM

Hello, all.

I am experiencing a somewhat rough idle in my Ford Ranger (vehicle details in my signature). It is not noticeable when I am driving the truck, so it's only when the RPMs are in the idling range. I think it should also be noted that the CEL is on in the truck. The interesting thing is that if I start the truck up, it idles nicely for a few seconds until the RPMs drop off, and then the CEL comes on.

I have to conclude that the two are interrelated. Also, I have replaced all of the spark plugs and wires with the help of my neighbor who was a mechanic. (In addition, I have replaced many other parts on the truck since I bought it a few weeks ago; just ask and I will let you know if I have done work on that part.) When I approached my neighbor about the rough idle, he said he thinks it was a lean misfire and that it wasn't a big deal. He and another guy were going to run diagnostics on it with a code reader, but it wasn't the right tool, so they weren't able to pull any codes. As a side note, the crappy exhaust that was on the truck when I bought it still on there; it's a full exhaust system (supposedly), but it doesn't exit out behind the bed.

My neighbor and the other guy think that the CEL is due to a worn out oxygen sensor. I just want to make sure that it's not something serious and that it's something that can be corrected. I welcome any input. Thanks.

ernestrulezd00d · #2 08-16-2011, 03:18 PM

Hey, guys. I still need some help. I went to O'Reilly's today after worked and pulled some codes via their scanner.

I got this while running a KOEO test:
DTC 223 Loss of dual plug inhibit (DPI) control

I got this while running a KOER test:
DTC 90 (There was no descripition; it just said to see the manufacturer's specific information.)
DTC 223 (Same as the KOEO test)
DTC 999 Operating in failure mode

Does anybody know what these mean? I really would like to know.

webster426 · #3 08-16-2011, 06:36 PM

My gut instinct would be to replace the primary (aybe even the secondary) O2 sensor and clean the MAF sensor and IAC....

Not familiar with the DTC codes so maybe someone else canhelp

ernestrulezd00d · #4 08-16-2011, 09:09 PM

Hey, webster426. Thanks for your input.

Long story short, I had the ignition control module tested at O'Reilly's, and it passed the test, so supposedly it's still functioning correctly. My neighbor and I cleaned out the IAC tonight and replaced it. We did not, however, clean the MAF. My neighbor seemed to think that it wasn't the type to be cleaned, but I have looked a little more on the internet and found information regarding cleaning it, so I think I'll do that tomorrow after work.

We also disconnected the black battery cable to dump the DTC codes. Once everything was reconnected, I started the truck up and it idled terribly, as was expected. After giving it gas for awhile, it started to smooth out but did not idle like I thought it should. The CEL was also off. I took it for a drive (as did my neighbor), and we both felt like it ran well at speed. I got back in it after my neigbor, started it up, and it bogged down and idled roughly. The exhaust also smelled bad, and the CEL came back on.

I am going to go back to O'Reilly's tomorrow after work to read the codes and see what comes up. My neighbor really feels that the exhaust makes the idle feel and sound worse than what it is and that the CEL is on because of something related to the exhaust.

ernestrulezd00d · #5 08-17-2011, 06:34 AM

UPDATE

I went out this morning to go to work, and when I started my truck, it idled so badly that it stalled. It did this several times, and I finally just started it and gave it some gas while pressing in on the clutch and shifting into reverse to keep it going. It was still idling badly at the end of the driveway, but once I got it up to speed, it seemed to be running pretty smoothly.

I would also like to note that the CEL was not on even though it was still on last night when I turned my truck off and parked it. It's about 20 miles one way from my house to work, and the light did not come on at all during the trip. I'm gonna go back after work to O'Reilly's anyway and see if I can pull any codes.

I did notice a new deveopment, however: The truck seemed to miss a few times at speed--like around/above 55 MPH, but other than that, it seemed tight. Once I got to work, I sat in the parking lot and let it idle for a bit just to see what it would do. It seemed smooth and tight, and the CEL did not come on.

I would appreciate any help with this. I'm just about at a loss as to what's going on.

ernestrulezd00d · #6 08-17-2011, 08:59 AM

I didn't mention that when I went to replace the air filter, I found that there was no filter in there. I thought this wasn't a big deal. Am I correct in assuming that this means the air being fed through the MAF to the engine was not being filtered? Could this lead to a dirty MAF and the idling/missing problems I've been experiencing?

ernestrulezd00d · #7 08-17-2011, 10:23 AM

I know that no one is replying to this thread, but I think I'll keep updating it in case someone wants to join in.

I just went out to the truck on my lunch hour and found out spark plugs three and four on the right side (compression side) of the engine were switched around. My question is this: Could incorrect wiring have damaged the coil pack?

As a side note, I used the recommended Motorcraft spark plugs when I replaced them, but I did not use the Motorcraft spark plug wires when the originals were taken off. Would it be a good idea to purchase the Motorcraft set? I plan on checking the plugs and such when I get off of work tonight.

Another possibility: I remember my neighbor telling me that he adjusted the idle to make it easier for me to take off from a stop since this is my first time driving a manual. Is it possible that this is the source of the problems?

webster426 · #8 08-17-2011, 02:44 PM

wow....you just purchased this thing? Wrong wires on spark plugs is definately going to cause a rough idle and should have been noticeable even at higher speeds. I am astonished that their was no air filter in their too.....

It depends how long the filter was out, by they are there for a reason! I have pulled airfilters with some pretty big and nasty debris in their before. Get a new filter, replace the plugs with motorcraft, clean the MAF.

Is this neighbor of yours a certified mechanic or just your neighbor?

ernestrulezd00d · #9 08-17-2011, 06:45 PM

Well, let me clarify: The original spark plug wires were routed correctly. We replaced the plugs with genuine Motorcraft plugs and had to replace the spark plug wires because we found a defect in one. We replaced the plug wires but not with Motorcraft ones since the general consensus was non-Motorcraft wires would not affect the ignition system. It was during the replacement of the wires that they became switched. I corrected the crossover of wires during lunch.

I did put a Fram air filter in there, and I will clean the MAF when I have time. As for my neighbor, I believe he's a mechanic by trade, but he was forced to retire after an injury. At any rate, he's got tons of knowledge; I don't know that he has ever been certified though. He's worked on our cars for awhile now and never let us down, but his expertise is not in electrical stuff, so on Monday I'm taking it to one of his friends who knows about auto electrical systems.

Back to the truck: After I corrected the plug wiring, the truck had better acceleration and top speed but upon starting, it still required gas to smooth out the rough idle and keep it going. The CEL did come back on today after work, so I tried to pull the codes at O'Reilly's, but I think I got codes that point to operator error (see below):

KOEO DTC 02 Visit www.canobd2.com
KOEO DTC 111 System pass
DTC 111 System pass, no continuous memory codes present

KOER Cyl: 4 Cylinder number
KOER DTC 412 Cannot control RPM during KOER high RPM check
KOER DTC 538 Insuffucient RPM change during KOER dynamic response test
Invalid cylinder balance test due to throttle movement during test

I Googled those codes, and that was the conclusion that I came to. I feel like I'm constantly in a House episode (the medical show from TV) because I have to decide what all the symptoms add up to. Oh, I also have been experiencing what I believe to be poor fuel economy, and after the CEL came on today, I experienced loss of power.

We did clean the IAC, but my neighbor tried to apply charge to the IAC to get it to move (he was trying to show me how it works). Even though he tried multiple wire configurations, he could not get the IAC to move. He told me that he has been able to activate them that way when taken from Chevys, and he assumed that the same would be possible. He was able to get it to turn with a pair of needle nose pliers, but I am wondering if that points to a defective IAC. Thoughts?

I really hope I can get this figured out. I desperately need to get this truck running well before I go out-of-state to school.

webster426 · #10 08-17-2011, 08:28 PM

I do not think your neighbor is mechanically included due to his "guess and test" theory that is having you purchase a bunch of parts. Keep It Simple Stupid (acryonm KISS)....if your having idle issues begin with idle related compenents LIKE THE IAC!

I am sticking to my original recommendation.....IAC and/or O2 sensors.

vishous · #11 08-17-2011, 08:52 PM

i believe the iac is bad too, you have to be very careful when cleaning them. but sounds like it is not working now with the codes u keep comming up with. also re check all plug wires and make sure they are correct. if they are good change iac and check plug burn. i have gotten new plugs that dont work cuz they drop them at the store. good luck

ernestrulezd00d · #12 08-17-2011, 09:03 PM

I would like to contend that my neighbor is extremely mechanically inclined and knowledgeable. It's just that electrical systems are not his expertise. All of the parts we replaced were necessary.

Anyhow, I will pull the plugs and check for fouling or burning and verify that the wiring order is correct. Is it possible that I performed the diagnostic scanner tests correctly and that those codes are relevant? Would they point to IAC problems?

Also, I don't know if this matters, but I have a whine of sorts (we joke about it being a turbo) that increases with acceleration or at least continues. It stops when disengage the clutch or stop and idle. I have read that that sound can be coming from the IAC or the black release cap thingy. Thoughts?

I really appreciate the input.

webster426 · #13 08-18-2011, 05:03 AM

Quote:

Originally Posted by ernestrulezd00d

Also, I don't know if this matters, but I have a whine of sorts (we joke about it being a turbo) that increases with acceleration or at least continues. It stops when disengage the clutch or stop and idle. I have read that that sound can be coming from the IAC or the black release cap thingy. Thoughts?

I really appreciate the input.

Does it sounds like it is coming from the tranny or the engine? Can you hear it if you are in neutral and rev the engine?

In regards to the tests....here are the directions:

http://www.therangerstation.com/tech_library/OBD_I.html

I think I remember you saying that you were applying throttle during the test to even out the idling....so most likely your test was inaccurate.

ernestrulezd00d · #14 08-18-2011, 07:03 AM

The noise only happens if I am revving the engine, and if I am decelerating, the noise starts to die off until I start idling. That's when it stops completely. If I put it in neutral and rev it, I get the whining noise. I don't believe that it is the tranny since it shifts nicely. Clutch is strong as well. I was told that another possibility was that it is part of the clutch mechanism spinning or belts or some electrical component kicking out noise.

When I was doing the tests, I did not attempt to even out the idle. I did my best to following the on-screen instructions that the scanner was giving me, but it is entirely possible that I messed up the sequence of events or didn't time the operations correctly. It was during the KOER test that I received DTC codes 412 and 538, and after some online research, it seems as though these codes are returned if there is operator error.

Also, there seems to be a pattern developing: I started the truck this morning, it idled terribly, and I had to give it gas to keep it from dying. Once I was driving, though, I regained the power I had lost last night, and the acceleration seemed a lot better. The CEL did not come on on the way to work. I was thinking over my problem and had a thought about the IAC: Is there supposed to be a gasket between where it meets up with the throttle body or whatever it's called? Because when we took that off to clean it, there was no gasket there. Maybe that could be the source of the idling problems?

handyandy · #15 08-18-2011, 08:50 AM

if it were my truck?leave it to go cold......unplug maf,start truck,it should idle but take a long time coming back down off the revs after the gas,if it idles fine,plug maf in,if rough idle returns its your maf,next (bare with me im from the uk)turn the idle back down to where it should be,ive not looked on mine yet,but there should be an ICV(idle control valve)this sensor tells the engine when its cold and to add choke,i'd say that the most likely suspect