Misfire Thread
04-05-2009, 01:59 PM
#21
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Originally Posted by Tom_B,Apr 5 2009, 07:39 AM
My 2002 started having misfires across all cylinders about 2 years ago. I took it to a local mechanic and he tried everything stated in the OP as well as a valve adjustment. None of that fixed it. He gave up and I gave in and took it to a Honda dealership.
They immediately diagnosed it with a faulty throttle body sensor; at idle it was sending a incorrect voltage to the ECU. Once the TB was replaced, everything ran smoothly. Have not had a problem since.
They immediately diagnosed it with a faulty throttle body sensor; at idle it was sending a incorrect voltage to the ECU. Once the TB was replaced, everything ran smoothly. Have not had a problem since.
04-05-2009, 07:18 PM
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Originally Posted by negcamber,Apr 5 2009, 09:05 AM
Compression should have been tested before trying the coils & injectors. Get it checked and report back. 
04-05-2009, 07:24 PM
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im hesitant to do it because if my compression is off, im royally screwed...if it was the compression causing a misfire tho, shouldnt it happen under load? please someone ease my mind a little bit if possible
04-06-2009, 12:45 AM
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Originally Posted by spectacle,Feb 13 2009, 05:54 AM
If your car doesn't like to stay alive at idle, remove your map sensor and clean the passage with brake cleaner. Mine was clogged up and causing all kinds of grief.
I had the dreaded misfire codes and my car couldn't keep an idle (intermittent). The problem was that my MAP sensor was not getting a good connection. I zip-tied it down and the problems haven't returned!!
04-07-2009, 11:33 AM
#27
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Originally Posted by negcamber,Apr 5 2009, 06:07 AM
Interesting...haven't heard that one before. The symptom I've generally seen from a bad TPS has been that the RPMs just fall flat at around 3k.
But I'll add this to the list since it is easy to check.
But I'll add this to the list since it is easy to check.
04-11-2009, 08:33 AM
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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!
04-11-2009, 06:41 PM
#30
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the only reason i allowed them to proceed with checking/changing valves is because i was told if that doesnt resolve the problem, the cost of the valve job will be applied to finding/fixing the issue if that doesnt do it