misfiring
#1
10-20-2006, 03:41 PM
misfiring
Just one experience with this kind of a problem. It may help.
I've read number of posts here and there with this or similar problem. When you have one or multiple cylindar misfire, your car will generally luck power, run porely when idling and will not accelerate.
When I had this problem first I had around 90,000km on my 97 Stratus. Engline light on, checked the code "cylinder misfire". Here is a short histor of how this problem developed during the time and things I did to fix it.
1. Replaced spark plugs. Bouth 4 champion RCI2YC5 and replaced as per manual. Problem dissapired for about 3 months.
2. Talked with a professional chrysler dealership mechanic and he suggested to replace the plug cables which I did. Bought Mopar cable set.
3. Neither me or him checked the condition of the spark plugs since they were basically new.
4. Car was running nicely for about another 3 months.
5. Talked to the same person again and he suggested to replace coil pack. Without checking it. Later, I've found that my old coil pack was within the specification (checked primary and secondary coil resistance).
6. Car was runninng fine for a week and the same problem started again.
7. This time my mechanic thinks it is (maybe) catalytic convertor. I read on internet that one way to check it is to measure the temperature difference on the inlet and the outlet. I found it is 200-170 dgr celsius (inlet-outlet). I am not sure is that normal or not so I go to Speedy, they look at the converter (from outside) and tell me that it looks ok. They were honest enough not to replace it without somebody else checking the actuall emission.
8. Next I borrow a car tester and check the code and find that Cylinder No. 3 is misfiring. I go and buy a set of four Platinum spark plugs and replace only No. 3. Car runs perfect (again). This time I remove two more sparkplugs and look closely. First thing I notice is that plugs are not actually the same. Even though the model is the same, one set is made in USA and other in Canada. One set has longer insulator. Maybe important, maybe not but I wonder about how the cable boot fits here?
I check the deposit on the plugs and it is tan, no oil. So looks ok. Than I talk to friend of mine and I ask him what he thinks about two lines visible on the insluator. Lines are black, 2mm wide and run almost all the way between top and bottom metal part of the plug. So what is it? Our conclusion is: sparks were arcing! Why? Probably because I've replaced the plugs but didn't replace the cables which were not as good anymore. Or I didn't put enough silicone so I had arcing. Repacing the cables helped for a while but new plugs already collected enough of the carbone deposit to cause misfire again.
Car is running fine for now. I will se if it will start doing the same thing after couple of months. But next time I will check my plugs before doing anything else.
This time I made sure I have same manufacturer spark-plugs as well.
Before I replaced spark plugs for the next time I did test with removing plug cables while the engine was running. My mechanic also told me that I do not do that for I can screw up the computer?!? But that is what manual says, so I trust the manual. I didn't screw up my computer obviously (BTW computers are partially my profession ...).
With every cylinder cable removed I would notice a drop in engine rpm so that test wouldn't be useful in this case.
Anybody else experienced similar thing?
(sory about my English)
I've read number of posts here and there with this or similar problem. When you have one or multiple cylindar misfire, your car will generally luck power, run porely when idling and will not accelerate.
When I had this problem first I had around 90,000km on my 97 Stratus. Engline light on, checked the code "cylinder misfire". Here is a short histor of how this problem developed during the time and things I did to fix it.
1. Replaced spark plugs. Bouth 4 champion RCI2YC5 and replaced as per manual. Problem dissapired for about 3 months.
2. Talked with a professional chrysler dealership mechanic and he suggested to replace the plug cables which I did. Bought Mopar cable set.
3. Neither me or him checked the condition of the spark plugs since they were basically new.
4. Car was running nicely for about another 3 months.
5. Talked to the same person again and he suggested to replace coil pack. Without checking it. Later, I've found that my old coil pack was within the specification (checked primary and secondary coil resistance).
6. Car was runninng fine for a week and the same problem started again.
7. This time my mechanic thinks it is (maybe) catalytic convertor. I read on internet that one way to check it is to measure the temperature difference on the inlet and the outlet. I found it is 200-170 dgr celsius (inlet-outlet). I am not sure is that normal or not so I go to Speedy, they look at the converter (from outside) and tell me that it looks ok. They were honest enough not to replace it without somebody else checking the actuall emission.
8. Next I borrow a car tester and check the code and find that Cylinder No. 3 is misfiring. I go and buy a set of four Platinum spark plugs and replace only No. 3. Car runs perfect (again). This time I remove two more sparkplugs and look closely. First thing I notice is that plugs are not actually the same. Even though the model is the same, one set is made in USA and other in Canada. One set has longer insulator. Maybe important, maybe not but I wonder about how the cable boot fits here?
I check the deposit on the plugs and it is tan, no oil. So looks ok. Than I talk to friend of mine and I ask him what he thinks about two lines visible on the insluator. Lines are black, 2mm wide and run almost all the way between top and bottom metal part of the plug. So what is it? Our conclusion is: sparks were arcing! Why? Probably because I've replaced the plugs but didn't replace the cables which were not as good anymore. Or I didn't put enough silicone so I had arcing. Repacing the cables helped for a while but new plugs already collected enough of the carbone deposit to cause misfire again.
Car is running fine for now. I will se if it will start doing the same thing after couple of months. But next time I will check my plugs before doing anything else.
This time I made sure I have same manufacturer spark-plugs as well.
Before I replaced spark plugs for the next time I did test with removing plug cables while the engine was running. My mechanic also told me that I do not do that for I can screw up the computer?!? But that is what manual says, so I trust the manual. I didn't screw up my computer obviously (BTW computers are partially my profession ...).
With every cylinder cable removed I would notice a drop in engine rpm so that test wouldn't be useful in this case.
Anybody else experienced similar thing?
(sory about my English)
#2
10-20-2006, 04:27 PM
RE: misfiring
Ok, from my old Neon days and some Stratus have the same 2.0L engine as the Neon. I know with them the rule was, change your oil, change your plugs. Don't waste your time with Bosh 4's. They do nothing but make your wallet lighter. Just pick up some Champion spark plugs for like $1 a piece. They are what the engine was designed to use and that is what it came from the factory with. Also when replacing spark plugs do all of them at the same time, not just one at at time. Spark plug wires don't have to be replaced at the same time spark plugs are replaced. Just normally people do them both at the same time. Also make sure you have the correct spark plug gap.
I know my Neon had the misfiring problems every once in a while. I started with replacing the plugs, then plugs and wires. That seemed to fix my problem. But replacing the coil pack is a good idea. I know there is an aftermarket one (I want to say MSD?) that seemed to help alot of Neon boys fix there misfire problem. Also have you reset your computer after changing any of these parts? That "misfire in 3" may be an old code. They normally don't clear untill you clear your cars computer. Just unhook your battery for about 15 minutes and it should clear the codes.
Yeah and don't un-plug spark plug wires with the engine running. That will rune your catalytic convertor and is just plan not good for your car. Think of it this way your are making your car run on 3 cylinders instead of 4 and that is not good for any engine (or 5 if you have the V6). Plus I am sure that can be dangerous to you as well, you may get shocked while pulling that wire.
I know my Neon had the misfiring problems every once in a while. I started with replacing the plugs, then plugs and wires. That seemed to fix my problem. But replacing the coil pack is a good idea. I know there is an aftermarket one (I want to say MSD?) that seemed to help alot of Neon boys fix there misfire problem. Also have you reset your computer after changing any of these parts? That "misfire in 3" may be an old code. They normally don't clear untill you clear your cars computer. Just unhook your battery for about 15 minutes and it should clear the codes.
Yeah and don't un-plug spark plug wires with the engine running. That will rune your catalytic convertor and is just plan not good for your car. Think of it this way your are making your car run on 3 cylinders instead of 4 and that is not good for any engine (or 5 if you have the V6). Plus I am sure that can be dangerous to you as well, you may get shocked while pulling that wire.
#3
10-20-2006, 08:08 PM
RE: misfiring
Thanks for answer; just couple of comments, maybe other will read ...
Yes, by model number you can tell my replacement plugs were Champion, but again slightly different. I didn't look, two were made in Canada, two in US and the difference in ceramic insulator is whole 5mm!
Places I shop have them only in packs of two. It makes sence to replace all four (6) of them at the same time, it is just couple of bucks.
Again, problem I had was that after 90,000km on your vehicle it is good idea to replace spark plug wires as well. Due to heat and constant stress dielectric property of your wire is not as good anymore. And I didn't do it right away which helped in building carbon arcing deposit on my plugs which later contributed to misfiring.
My point was that nobody with similar problem never mentioned something like this. People were doing all sort of stuff where maybe they didn't have to. Also I've never found picture of this kind of deposit on spark plugs. Manual mention deposit on the electrodes and craks on the insulator but never trace of ARCING. New to me.
I agree there. After some miles on your car it is good idea to replace many things ... I will keep in mind that MSD company. This time I've used Mopar one but some other company makes that for Mopar. They just selling others stuff I think.
Yes, my computer was reset and light off. Sometimes it would clear by itself.
This procedure is suggested in Haynes manual and I've read it on ARRC (Auto Repair Reference Center) - access through my library card. This should be only short test. When you have engine misfire condition and Engine Trouble light ON, that is already danger for catalytic convertor so runing engine on three cylinders for a second or two will not hurt converter. To avoid shock, manual recommends using rubber gloves. But even without them you will not get shocked unless the cables are really bad.
Just pick up some Champion spark plugs for like $1 a piece.
Also when replacing spark plugs do all of them at the same time, not just one at at time.
Again, problem I had was that after 90,000km on your vehicle it is good idea to replace spark plug wires as well. Due to heat and constant stress dielectric property of your wire is not as good anymore. And I didn't do it right away which helped in building carbon arcing deposit on my plugs which later contributed to misfiring.
My point was that nobody with similar problem never mentioned something like this. People were doing all sort of stuff where maybe they didn't have to. Also I've never found picture of this kind of deposit on spark plugs. Manual mention deposit on the electrodes and craks on the insulator but never trace of ARCING. New to me.
But replacing the coil pack is a good idea. I know there is an aftermarket one (I want to say MSD?) that seemed to help alot of Neon boys fix there misfire problem.
Also have you reset your computer after changing any of these parts? That "misfire in 3" may be an old code.
Yeah and don't un-plug spark plug wires with the engine running. That will rune your catalytic convertor and is just plan not good for your car. Think of it this way your are making your car run on 3 cylinders instead of 4 and that is not good for any engine (or 5 if you have the V6). Plus I am sure that can be dangerous to you as well, you may get shocked while pulling that wire.
