Stumped - Misfire at Idle ONLY
08-29-2010, 02:16 AM
#11
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Originally Posted by Eyal s2k,Aug 25 2010, 04:56 PM
Recently my Catalytic convert failed and has been rattling, the core came loose. (Running lean during misfire that damaged the cat? The car is also has over 100K miles)
Here is what I've done so far:
-Switch Coil #3 and #2 (cylinder 2 is often the last to code a misfire) - No change, misfire still started in #3 and #2 is often the last to code
- Ultrasonically cleaned all 4 injectors - car felt slightly smoother, but no change in misfire idle issue.
- Cleaned ISV - car felt better, but no change in Misfire issue
- Replaced MAP with brand new OEM unit
- Replaced spark plugs
Here is what I've done so far:
-Switch Coil #3 and #2 (cylinder 2 is often the last to code a misfire) - No change, misfire still started in #3 and #2 is often the last to code
- Ultrasonically cleaned all 4 injectors - car felt slightly smoother, but no change in misfire idle issue.
- Cleaned ISV - car felt better, but no change in Misfire issue
- Replaced MAP with brand new OEM unit
- Replaced spark plugs
09-29-2010, 11:51 AM
#14
UPDATE: I had a valve adjustment done, and replaced the catalytic converter along with the secondary 02.
The car hits VTEC now, and feels better than it has in a very long time, however I still do pull misfire codes at idle. At first it seemed like they came up much less often, but over the past couple weeks, they misfire codes come up as often as before.
I reset/erase the ecu when the codes come up sometimes to see how fast they return, and I often end up getting code P0410 and P0411. I had seen P0410 a couple times before, but the frequency of this code has increased. I have heard the air pump come on at idle when the car is fully warmed up before. P0411 is pretty new. My intake is stock, and I have never touched any of the vacuum system.
I think my next move is to replace the airpump, and the injectors. Let me know if you agree or not.
Also, if any of you have a pump or injectors to sell me, please feel free to PM me.
Thanks for all the help so far!
The car hits VTEC now, and feels better than it has in a very long time, however I still do pull misfire codes at idle. At first it seemed like they came up much less often, but over the past couple weeks, they misfire codes come up as often as before.
I reset/erase the ecu when the codes come up sometimes to see how fast they return, and I often end up getting code P0410 and P0411. I had seen P0410 a couple times before, but the frequency of this code has increased. I have heard the air pump come on at idle when the car is fully warmed up before. P0411 is pretty new. My intake is stock, and I have never touched any of the vacuum system.
I think my next move is to replace the airpump, and the injectors. Let me know if you agree or not.
Also, if any of you have a pump or injectors to sell me, please feel free to PM me.
Thanks for all the help so far!
10-01-2010, 11:14 AM
#15
I forgot to mention, the tech that did the valve adjustment told me that the spark plugs needed to be replaced. Those plugs probably had about 20,000 miles and a little over a year on them.
I replaced them, but no difference with the misfire (as expected)
Another observation is that for a short idle of a few seconds, it doesnt have an issue, but if I idle for a while, the longer I idle, the more the car starts to misfire until i finally get a flashing cel.
Running the AC makes it a little worse.
I just bought a set of injectors, will update when I get those in. Meanwhile, any insight is greatly appreciated.
I replaced them, but no difference with the misfire (as expected)
Another observation is that for a short idle of a few seconds, it doesnt have an issue, but if I idle for a while, the longer I idle, the more the car starts to misfire until i finally get a flashing cel.
Running the AC makes it a little worse.
I just bought a set of injectors, will update when I get those in. Meanwhile, any insight is greatly appreciated.
10-18-2010, 03:38 PM
#16
Update: I installed the replacement set of injectors. When I was in there I found the small vacuum hose that connected to the metal vacuum line that bolts to the rail had been completely disconnected. (I think the shop may have left it off accidentally when doing the valve job)
That being said, I still have the same issue.
I don't get P0411 anymore, but I still get the misfire codes at idle.
My cam chain tensioner needs to be replaced, is it possible that its so bad that its not tensioning the chain enough at idle (lowest oil pressure) enough to throw timing off on the cam to cause a misfire?
That being said, I still have the same issue.
I don't get P0411 anymore, but I still get the misfire codes at idle.
My cam chain tensioner needs to be replaced, is it possible that its so bad that its not tensioning the chain enough at idle (lowest oil pressure) enough to throw timing off on the cam to cause a misfire?
10-18-2010, 05:10 PM
#17
Moderator
NO way the TCT (timing chain tensioner) is causing a misfire.
Tight valves can cause a misfire at idle. Not loose valves.
first things first. find someone who knows how to read and decipher fuel trim. This way you can eliminate 50% of possible causes right off the bat, by determining if a rich or lean condition is causing the misfire.
Tight valves can cause a misfire at idle. Not loose valves.
first things first. find someone who knows how to read and decipher fuel trim. This way you can eliminate 50% of possible causes right off the bat, by determining if a rich or lean condition is causing the misfire.
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