Random Misfire
06-01-2010, 12:34 PM
#1
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Random Misfire
Well the car had gone over 100000 without a single component breaking so I guess I was just waiting for something like this...
While driving the car back from the shop which had just replaced the engine mounts (they were replaced after 100000), the check engine light came on. They were already closed for the weekend so I figured I'd check it out at home. The code was a slow response on the O2 sensor. I cleared it figuring that they may have bumped it or something and that if it was a problem it would trigger again. Well it did but not immediately. I still drove the car (very short distances) and ignored it, figuring I'd get around to it.
Today I drove my father to the airport among other things racking up about a 130 mile journey. At the end, the TCS light was on as well. When I checked the codes it revealed that there had been codes on a misfire on cylinders 1-6 as well as random misfire and another related to ignition or misfire. After searching around I believe that a cleaning of the O2 sensor is in order?
I was planning on unplugging it electrically and plugging it back in, erasing the code and seeing if it appears again. Would you guys recommend I just remove it and clean it before driving it any more than necessary?
Thanks for any help.
Note: Someone should allow the search on acurazine to search the short "O2" currently it ignores it as too short.
While driving the car back from the shop which had just replaced the engine mounts (they were replaced after 100000), the check engine light came on. They were already closed for the weekend so I figured I'd check it out at home. The code was a slow response on the O2 sensor. I cleared it figuring that they may have bumped it or something and that if it was a problem it would trigger again. Well it did but not immediately. I still drove the car (very short distances) and ignored it, figuring I'd get around to it.
Today I drove my father to the airport among other things racking up about a 130 mile journey. At the end, the TCS light was on as well. When I checked the codes it revealed that there had been codes on a misfire on cylinders 1-6 as well as random misfire and another related to ignition or misfire. After searching around I believe that a cleaning of the O2 sensor is in order?
I was planning on unplugging it electrically and plugging it back in, erasing the code and seeing if it appears again. Would you guys recommend I just remove it and clean it before driving it any more than necessary?
Thanks for any help.
Note: Someone should allow the search on acurazine to search the short "O2" currently it ignores it as too short.
06-01-2010, 05:07 PM
#2
when you have a short search like that- use an internet engine for the subject +acurazine.com
that works really well
Random and multi misfire is usually 1 coil has gone bad
the computer sends out bizzare signals and different warning lights to get your attention
Were the spark plugs replaced recently? coil often damaged during that service by mishandling
Or does it simply need spark plugs because its at 100- their max life
if you want to reset the ecu to clear codes- pull the CLOCK fuse on pass side dash end fusebox--thats secret backup power to ecu
Never heard an O2 sensor cause this- where did you get that info
that works really well
Random and multi misfire is usually 1 coil has gone bad
the computer sends out bizzare signals and different warning lights to get your attention
Were the spark plugs replaced recently? coil often damaged during that service by mishandling
Or does it simply need spark plugs because its at 100- their max life
if you want to reset the ecu to clear codes- pull the CLOCK fuse on pass side dash end fusebox--thats secret backup power to ecu
Never heard an O2 sensor cause this- where did you get that info
06-01-2010, 05:08 PM
#3
how do you bump an o2 sensor around-?? its installed inside the exhaust pipe- with the external part and wire barely exposed--
06-01-2010, 07:19 PM
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Sorry I don't have much experience with the stuff but i figured it might have been possible that they bumped the plug.
My searches showed one guy who was recommended to check the sensor plug after a car wash as well as another who replaced coils only to find that all he needed was to clean his o2 sensor. I did replace the spark plugs with my father at around 100000 thinking that they must need changing. That was in the winter. The car ran fine and never triggered a code until it was on the way back from the shop. That was my reasoning behind it.
My searches showed one guy who was recommended to check the sensor plug after a car wash as well as another who replaced coils only to find that all he needed was to clean his o2 sensor. I did replace the spark plugs with my father at around 100000 thinking that they must need changing. That was in the winter. The car ran fine and never triggered a code until it was on the way back from the shop. That was my reasoning behind it.
06-02-2010, 05:53 AM
#5
did you install ngk Iridium or ngk platinum spark plugs?
or some other off brand the car doesnt like and has eaten the plugs? has happend more than once on bosch and autolite and others
the TL is very picky about plugs
Pull a few to inspect
car washes that soak the underbody can cause problems
Never seen a TL need the O2 sensor cleaned- it works or it doesnt- there is an electrical test for it before replacment is deemed necessary
Did shop use acura mounts- and the right ones? - some years are vacuum boosted and an open vac line will cause running issues
It ran ok when you took it in- take it back and let them ck their work or find the new problem
or some other off brand the car doesnt like and has eaten the plugs? has happend more than once on bosch and autolite and others
the TL is very picky about plugs
Pull a few to inspect
car washes that soak the underbody can cause problems
Never seen a TL need the O2 sensor cleaned- it works or it doesnt- there is an electrical test for it before replacment is deemed necessary
Did shop use acura mounts- and the right ones? - some years are vacuum boosted and an open vac line will cause running issues
It ran ok when you took it in- take it back and let them ck their work or find the new problem
06-10-2010, 04:23 PM
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Sorry its been so long.
The plugs installed were ngk Iridium. We installed them using the DIY on this site.
I checked the mounts and they are correct. The front one is connected to the vacuum line.
I have some more information that may or may not be helpful. I usually drive the car no more than 15 miles a day and the light did not come on for a week. But upon making a 40 mile trip to the nearest city the light came on and when I checked there was another misfire. Thus it must be either distance or speed related. Both misfires happened at around 70 MPH I believe. (I think it was 69 and 71). This second time though only three cylinders misfired rather than all six. If it is indeed the coils, what would I look for (or at for that matter)? I looked at one of the springs inside the tube thing just now and it looked perfectly fine if that's what you're talking about. Does any of this info help the diagnosis?
The plugs installed were ngk Iridium. We installed them using the DIY on this site.
I checked the mounts and they are correct. The front one is connected to the vacuum line.
I have some more information that may or may not be helpful. I usually drive the car no more than 15 miles a day and the light did not come on for a week. But upon making a 40 mile trip to the nearest city the light came on and when I checked there was another misfire. Thus it must be either distance or speed related. Both misfires happened at around 70 MPH I believe. (I think it was 69 and 71). This second time though only three cylinders misfired rather than all six. If it is indeed the coils, what would I look for (or at for that matter)? I looked at one of the springs inside the tube thing just now and it looked perfectly fine if that's what you're talking about. Does any of this info help the diagnosis?
Nevermind about the coils. Just wikipediaed it.
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06-10-2010, 05:39 PM
#8
You can do a Balance Test. I think that what it's call. Not hard to do just be careful not to get shock.
Do what you did when you installed new Spark plug.
Refresh your remember.
1st you remove 6mm Allen holding the coil pack in place. Next remove spark plug out an make sure there a gap on each spark plug. What I mean is make sure there gap on each spark plug end. Sometime they get drop by auto parts guy an you may have not notice this before you installed it. If everything Look GOOD put everything back together an leave out putting in 6mm Allen screw that hold coil pack in place.
Now this How you do Balance Test.
1. Started your engine
2. Pull out one of the coil pack half way out of the plug.
You will heard spark from making some popping noise that's Normal.
Now after doing that your engine should start jump back an forth or shaking more then before that mean: Coil pack is GOOD. Now put it back IN.
3. Now go to next 1.
Now if you pull one of there coil pack out half out NOTHING changes that mean you have found the problem. It mean Coil pack is bad.
It's easy to do this then typing it up. I had to do this Last week when i Had misfire when finishing up my Swap.
Do what you did when you installed new Spark plug.
Refresh your remember.
1st you remove 6mm Allen holding the coil pack in place. Next remove spark plug out an make sure there a gap on each spark plug. What I mean is make sure there gap on each spark plug end. Sometime they get drop by auto parts guy an you may have not notice this before you installed it. If everything Look GOOD put everything back together an leave out putting in 6mm Allen screw that hold coil pack in place.
Now this How you do Balance Test.
1. Started your engine
2. Pull out one of the coil pack half way out of the plug.
You will heard spark from making some popping noise that's Normal.
Now after doing that your engine should start jump back an forth or shaking more then before that mean: Coil pack is GOOD. Now put it back IN.
3. Now go to next 1.
Now if you pull one of there coil pack out half out NOTHING changes that mean you have found the problem. It mean Coil pack is bad.
It's easy to do this then typing it up. I had to do this Last week when i Had misfire when finishing up my Swap.
06-10-2010, 06:11 PM
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Is this test designed for constant misfire? The car isn't always misfiring. It has misfired only when I take it on the interstate trips.
This test only works if its misfiring all the time right?
This test only works if its misfiring all the time right?
06-10-2010, 06:47 PM
#11
the rear motor mount is vac boosted too- ck the line to both just to know its all good
no leak in line anywhere
have you had the codes checked after it does it this most recent time?
thats what we need now- if a light flashed there should be stored code
those are clues not direct diagnosis
Do you feel an actual misfire,,hesitation, loss of power, or just getting the light
1 cylinder not firing will make it run bad, 2 would be barely running
gas mileage would suffer
at this point- I would buy 1 coil at 50 bucks, put it on the first cyl listed in the misfire readout -reset ecu by pulling clock fuse for a minute
You must do the ecu reset with each change you make when trying to find a miss
If the car runs better... you are done!
if you get light on test drive, let it cool and move the new coil to next listed possible cyl --reset ecu and test drive
When it runs better and no light, you found the bad coil~
No way to tell by looking at them inside
There is a specific electrical test you can do- I dont have it- sorry..at 100 and plug change now miss = plug with way wrong gap, or bad coil
when you pull each coil remove the spark plug and inspect
If the electrode is flat horizontal its probably good
A wet plug- moist with fuel, is a non firing cylinder- see coil failiure
You can tell a plug that not like the others- they should all match with a nice tannish grey on the side/edge of electrode
no leak in line anywhere
have you had the codes checked after it does it this most recent time?
thats what we need now- if a light flashed there should be stored code
those are clues not direct diagnosis
Do you feel an actual misfire,,hesitation, loss of power, or just getting the light
1 cylinder not firing will make it run bad, 2 would be barely running
gas mileage would suffer
at this point- I would buy 1 coil at 50 bucks, put it on the first cyl listed in the misfire readout -reset ecu by pulling clock fuse for a minute
You must do the ecu reset with each change you make when trying to find a miss
If the car runs better... you are done!
if you get light on test drive, let it cool and move the new coil to next listed possible cyl --reset ecu and test drive
When it runs better and no light, you found the bad coil~
No way to tell by looking at them inside
There is a specific electrical test you can do- I dont have it- sorry..at 100 and plug change now miss = plug with way wrong gap, or bad coil
when you pull each coil remove the spark plug and inspect
If the electrode is flat horizontal its probably good
A wet plug- moist with fuel, is a non firing cylinder- see coil failiure
You can tell a plug that not like the others- they should all match with a nice tannish grey on the side/edge of electrode
06-10-2010, 06:53 PM
#12
leaving super high voltage wires unplugged is a bad idea for testing !!
and can result in false good read on bad coil,,subtle change in rpm ...
I read on here (do at own risk-disclaimer)
someone recently plugged a good spark plug into the suspect coil and ground plug to block (somewhere metal) and crank engine several times (requires trusted friend)
Its the old school way of testing plugs wires coil-
watch for bright blue spark=good - or weak yellow or no spark=bad part
and can result in false good read on bad coil,,subtle change in rpm ...
I read on here (do at own risk-disclaimer)
someone recently plugged a good spark plug into the suspect coil and ground plug to block (somewhere metal) and crank engine several times (requires trusted friend)
Its the old school way of testing plugs wires coil-
watch for bright blue spark=good - or weak yellow or no spark=bad part
06-11-2010, 12:18 PM
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The main issue is that it doesn't happen consistently so seeing if it misfires again is hard to do. The car has felt just wrong. Perhaps sluggish? I have a code reader. The codes I got the first time were:
O2 slow response
Misfire cylinder 1
Misfire cylinder 2
Misfire cylinder 3
Misfire cylinder 4
Misfire cylinder 5
Misfire cylinder 6
Random/Multiple Misfire Detected
The more recent time:
Misfire cylinder 1
Misfire cylinder 4
Misfire cylinder 6
Random/Multiple Misfire Detected
In both cases the TCS light also came on.
Once again, the light for the misfire has only come on twice. It has not reported that it has been constantly misfiring.
I was hoping for some consistency between the misfires.... 1,4, and 6 are not the same bank are they?
I will try checking for leaks and whatnot. Listen for any hissing. If everything still looks good I guess I'll buy another coil.
O2 slow response
Misfire cylinder 1
Misfire cylinder 2
Misfire cylinder 3
Misfire cylinder 4
Misfire cylinder 5
Misfire cylinder 6
Random/Multiple Misfire Detected
The more recent time:
Misfire cylinder 1
Misfire cylinder 4
Misfire cylinder 6
Random/Multiple Misfire Detected
In both cases the TCS light also came on.
Once again, the light for the misfire has only come on twice. It has not reported that it has been constantly misfiring.
I was hoping for some consistency between the misfires.... 1,4, and 6 are not the same bank are they?
I will try checking for leaks and whatnot. Listen for any hissing. If everything still looks good I guess I'll buy another coil.
06-11-2010, 09:32 PM
#14
rear cyl 123,, front 456
07-18-2010, 10:45 AM
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I know its been a good month but I figured out the problem. I figured I'd let everyone know so that another cause of the 02 sensor error and misfire error can be checked.
When you mentioned open vacuum lines, you reminded me of the instructions to the thermoblock spacers I had installed while cleaning in the winter months. They said to recheck and tighten the bolts after a couple weeks. Well I decided to do that before anything else and found that not only did the bolts need some tightening but I had put the gasket on the wrong way.
Ever since tightening the bolts and putting it back together CORRECTLY the car has been working perfectly.
It seems that it really does require user error to screw up these vehicles. Thanks for the help everyone.
When you mentioned open vacuum lines, you reminded me of the instructions to the thermoblock spacers I had installed while cleaning in the winter months. They said to recheck and tighten the bolts after a couple weeks. Well I decided to do that before anything else and found that not only did the bolts need some tightening but I had put the gasket on the wrong way.
Ever since tightening the bolts and putting it back together CORRECTLY the car has been working perfectly.
It seems that it really does require user error to screw up these vehicles. Thanks for the help everyone.
07-18-2010, 03:45 PM
#16
was it that very top gasket? its easy to have it flipped over and not be able to tell
match it to the upper cover side- thats the trick holes it covers if wrong
Yes to retorque intake and exhaust bolts (if you worked on exhaust) after 500 miles
match it to the upper cover side- thats the trick holes it covers if wrong
Yes to retorque intake and exhaust bolts (if you worked on exhaust) after 500 miles
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