Misfire Thread
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From: DFW
Originally Posted by dave2k,Apr 11 2009, 11:33 AM
First time posting, thought I would share my misfire story to see if anyone might have advice. I have a 2001, totally stock. Codes started at 40K although no symptoms were present. Codes read by the dealer were 307 (? perhaps 301?), 302, 303, 304, 300. The did a leakdown test with results of 10% 20% 15% and 20%. Recommended a full head replacement. I declined. CEL reappeared but was intermittent for quite some time. CEL became constant again at 46K, returned to dealer who found codes 302 and 304. They switched the coils around to eliminate them as a cause. CEL returned quickly. The only noticeable symptom is roughness at idle. Above idle it seems to be totally normal. At 48K I went to a trusted independent shop for a second opinion before paying for a new head or a valve job. I provided the CEL history to the independent. They found codes 301, 302, 303, 304, 300, 1399. They checked compression and found results of 225 - 245, said to be acceptable. They checked the plugs and used a scope to check the valves and pistons, which looked OK. They flushed the fuel system and ran fuel injector and valve cleaner through the system. They moved what they thought was the worst injector to see if that would make a change. The car ran better than ever after this service, but the improvement wore off within less than a tank of gas. I added valve and injector cleaner to my next two tanks of gas. CEL returned and I returned to the independent. They said the injector relocation didn't make any difference and they replaced the plugs. No improvement was seen.
I've read a number of posts and I'm encouraged that my problem is not unique although it is also not easy to solve. I'm leaning away from the valves being the problem, not because the cost is scary, but because the problem has been somewhat intermittent and I saw improvement after the fuel system flush and cleaner additives. Seems that these would have no impact on bad valves. I'm leaning towards the injectors as the cause of the problem. I guess it could also be the throttle body or throttle position sensor. I could also use a valve adjustment perhaps. I doubt the MAP sensor would be impacted by the fuel system flush, but I'm not sure. I wonder if one injector could be replaced to see if that stops the misfiring in that cylinder? I welcome any advice as I hope to cure the problem before reaching the end of the long repair list as some have. I think the S2000 is a great car, but it sure would be more enjoyable if the idle was smooth and the CEL was not visible!
I've read a number of posts and I'm encouraged that my problem is not unique although it is also not easy to solve. I'm leaning away from the valves being the problem, not because the cost is scary, but because the problem has been somewhat intermittent and I saw improvement after the fuel system flush and cleaner additives. Seems that these would have no impact on bad valves. I'm leaning towards the injectors as the cause of the problem. I guess it could also be the throttle body or throttle position sensor. I could also use a valve adjustment perhaps. I doubt the MAP sensor would be impacted by the fuel system flush, but I'm not sure. I wonder if one injector could be replaced to see if that stops the misfiring in that cylinder? I welcome any advice as I hope to cure the problem before reaching the end of the long repair list as some have. I think the S2000 is a great car, but it sure would be more enjoyable if the idle was smooth and the CEL was not visible!
I'm not saying your problem is a map sensor, but it wouldn't hurt to zip tie it down if it isn't already.
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From: Jacksonville, FL
Originally Posted by dave2k,Apr 11 2009, 11:33 AM
I'm leaning towards the injectors as the cause of the problem.
If the injector cleaning helped, then it is almost certainly the injectors that are the problem. I would change them all before I did anything else...if one is going bad, the others aren't far behind.
One of the first owners to battle the misfire problem went through multiple injector cleanings that would last for a while but not be a permanent fix. Once replaced, the problem was gone.
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From: Miami
this just in...apparently there were some damaged valve guides, or seats or both in addition to the valves. ill report back exactly when i see the bill. also, they're replacing all the valves even tho they werent all damaged. total out the door with tax $1875 greenbacks.../life
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I wouldn't be surprised if most S2000 owners (with multiple misfire codes), find that the fuel injectors and/or fuel system are the reason for their problems. I have had all the misfire codes mentioned. I did the MAP whack and added zip ties. It did nothing. Took the car to the dealership where they did leak down and compression tests, and everything checked out perfect. Anyway, after going through the rounds... I had the injectors replaced with brand new OEM injectors, and I also had the fuel pump and FPR replaced with new OEM ones. Car has run strong with zero issues for the last 8 months. I contribute all my misfire issues on basically the entire fuel system. haha
This all occurred on a MY01 w/ 68,500 miles (at the time). Now at 72,200 miles and running perfect.
This all occurred on a MY01 w/ 68,500 miles (at the time). Now at 72,200 miles and running perfect.
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From: ontario
Originally Posted by Reds2kracer,Apr 16 2009, 11:12 PM
Well, I'd took the S for a drive (60 miles) and the CEL hasn't been back (fingers crossed). I still hear that slight pop from my exhaust though, only at idle cuz you won't be able to hear it once the revs goes up. Any ideas?
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From: Miami
i've got about 300 mi after these morons changed my exhaust valve guides and its not back on yet(crosses fingers)...i dont understand how the machine shop didnt change the valves...i guess since the warranty on the job is only 1yr or 12k mi they can afford to do shitty jobs
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From: Miami
so i just got off the phone with the machine shop. at first the poor guy who must be so beaten down by rick case, didnt even want to discuss the job with me. then after i explained to him how these dooshes are treating me, he softened up. and when he realized i had the invoice, he explained it to me willingly. the valves all checked out ok he said. they werent bent. but the exhaust valve guides were bad. also he said had the valves been bad they would have told rick case to provide valves...he says the head is good as new, so i feel a little bit better now
theres got to be some way i can use the actual bill from rick case that says there were bent valves, and that guys statement that they were fine, to own these assholes...ffffuuuuuuu i didnt get it on tape. but his invoice doesnt say anything about bent valves
theres got to be some way i can use the actual bill from rick case that says there were bent valves, and that guys statement that they were fine, to own these assholes...ffffuuuuuuu i didnt get it on tape. but his invoice doesnt say anything about bent valves
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From: Minnesota
Originally Posted by 00wreckedS,Apr 20 2009, 09:33 AM
how is car running after changing injectors?
Oh and for those that are gonna replace their injectors, make sure you inspect (very important) both the rubber gaskets first before you install them in, also make sure to oil them like someone mentioned earlier in the thread.