QuestionHello Roland,
The plugs were changed about a year ago. The O2 sensors were changed at random, 1st one around 2 years ago, 2nd about 1 year ago, 3rd six months and the last was changed after it started running rough because of the 21 code. It made no difference. I changed the 3 front plugs just because they are easy to get to and to see if it made a differnce, it did not. I have a caravan with the same egr valve so I swapped those and it made no difference. I cleared the codes then drove it around 10 miles till the light came back on, this time it reads 12 & 43. I will go ahead and change the rear 3 plugs and put a new upper manifold gasket in soon, I sure don't hear any vacuum leaks. I didn't think it could be anything mechanical because at first it would still run great about 50% of the time but now it is running bad almost all the time. Any addition thoughts? Thank you again, Fred
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Followup To
Question -
Hi, thanks for your help, if this means anything I gave you wrong information on my first question. I wasn't getting a code 11, I was getting codes 12, 21 & 43. I know 43 is multiple cylinder misfiring but that it dosen't tell which one or why. Would the Chrysler DRB III reader pinpoint the reason? Thanks again, Fred
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Followup To
Question -
Hi,
I have a 97 Sebring coupe with 2.5L, started missing while idleing and at speeds between 40 to 45 mph it jerks real bad. It was getting code readings #11, 12 & 21. All four O2 sensor are new, new plugs, wires cap & button. Any thoughts?
Thanks, Fred
Answer -
Hi Fred,
With the '97 vehicle you are in the OBD II system as you probably know and that system involves greater complexity. The code readings 11, 12, and 21 are useful but they are from the old OBD I system. A more up to date reader would give you more detailed information about the trouble codes that are stored. But let me suggest one thing: the code 11 for example has four possible sub-explanations related to the crankshaft sensor missing or intermittant, or misfiring reaching a limit, or timing belt skipped a tooth, that a Chrysler DRB III reader would differentiate. Similarly the code 21 has five possible sub-explanations for O2 problems (heater failure, shorted to voltage, shorted to ground, slow response, stays at center) and the DRB II furthermore can tell you which of the four O2 sensors is misbehaving. 12 code means the power to the engine controller has been disconnected sometime in the past 40 key on-off cycles.
Because I don't know the history of your problem fully, and what type of reader was used and at what point in the process of making the part replacements, it is difficult for me to tell you exactly what to do next. I would lean toward going to a Chrysler or Dodge dealer who has a tune-up mechanic with a good track record and turning the problem over to him to diagnose with the DRB II reader and also the Mopar Diagnostic System. I am not one to recommend this regularly, but it sounds like you have put in many new parts to no avail. A skilled tech can probably figure it out quickly without too much labor time involved.
I would be interested to know if you take that route what the answer was. Also feel free to ask me another question or give me more info on the history.
Roland
Answer -
Hi Fred,
Well I guess it is better to not have the 11 code for that takes the spotlight off of the crankshaft sensor. That one, if present, would have been further clarified with the DRB III reader. So on the 43, the only thing the DRB III would add is which cylinder(s) is misfiring, not why. The list of possible reasons given in the troubleshooting manual is long, and it is suggested that it be pursued in order:
secondary ignition wiring and timing
engine vacuum
PCM power and grounds
Engine mechanical
MAP sensor
Intake air temp sensor
Do you recall when this began and what it might have been related to at that time? What prompted you to replace all four 02 sensors? The DRB III would identify which sensor is not working properly and why, but you would want to ascertain that the code is still relevant. Were the old codes erased after you did the O2 replacing?
I know that to replace the plugs on the rear bank of cylinders a lot of dismantling is required. How about that work? Did the problem begin at that time? If so it could be a vacuum leak in the manifold seal for example.
You might try disconnecting the battery for a few minutes to see if that causes all the codes to erase (at least it did on the OBD I system), see if it erases them and then see what codes reset after a few trips.
I wish I could point you right to the solution but that is not in the cards.
Roland
AnswerHi Fred,
I got my PC fixed today, so am responding to your email this way again. I weak coil could be intermittant, sure.
Here are the checks values/tests for the coil, based on the '96 Cirrus manual for the 2.5L engine:
To check for the coil's wiring to the rest of the system, note that there is a 6-way and a 2-way (with only 1 wire) connector to the coil/distributor. Using an ohmmeter:
check for continuity between pin 11 of the pcm and pin 1 of the 6-way (black/gray) which is the ignition coil driver wire;
check for contiunity between 6-way pin 2 (black) and ground;
check for continuity between PCM pin 6 and pin 2 of the 2-way connector (dark green/orange or black/red?) which is the ASD relay output wire;
check the resistor in the distributor cap itself:measure between the center button and the ignition coil terminal; it should be about 5,000 ohms.
You can check the primary of the coil by measuring the resistance between the socket at the coil where the single wire (black/red or dark green/orange?) of the 2-pin connector is normally connected and a ground: it should be 0.6 to 0.8 ohms
The secondary coil resistance can be measured between the coil tower and the same point as just described above on the 2-way socket at the coil: it should read 12 to 18k ohms.
There is a resistor in the distributor cap: it should read 5,000 ohms between the center button and the tower terminal.
Check the rotor for continuity (no resistance value is given in the manual).
I'll be interested to learn what you find out.
Roland
Hi Fred,
Sorry to be a bidt slow in replying, my PC's hard drive crashed and so I can only send and receive email (I am borrowing a neighbor's PC to respond to you). So use rfinston@pacbell.net to write me back in the immediate future.
I think you have covered all the possibilities that come to my mind. The egr is always a suspect for rough idle. Other mixture control items would also be relevant, but you seem to have those under control. How about the distributor cap and rotor? Do you see any arcing around the wires or cap when you view them in the dark?
Let me know if you find the source of the problem or have any questions.
Roland
