cylinder misfiring
#1
cylinder misfiring
please someone help. all the cylinders are mis firing the dealer says its because of cylinder five and that i need a new cylinder head or a new block there is only12000 miles on the car. all the coil packs and plugs are good can someone give me sum input. is there a way to see if the o2 sensor is bad.
thanks
thanks
#3
A bad O2 sensor won't cause a dead miss. Hopefully the dealer took a compression test and found out that #5 is kaput. If the dealer took a compression test, what were the results? Could be many problems, from valves, camshaft, head itself, block, etc. Have even seen a fuel injection go bad/clogged and cause a non firing cylinder, but not low compression. Many reasons, but you'll need to find out what the dealer did, or didn't do to come his decision.
If under warranty, why worry about a fix if you not familiar with the car? Just let them do the work, or take it to another dealer for a second opinion.
If under warranty, why worry about a fix if you not familiar with the car? Just let them do the work, or take it to another dealer for a second opinion.
#4
Originally Posted by jon34
please someone help. all the cylinders are mis firing the dealer says its because of cylinder five and that i need a new cylinder head or a new block there is only12000 miles on the car. all the coil packs and plugs are good can someone give me sum input. is there a way to see if the o2 sensor is bad.thanks
Ask them *HOW* they came to that conclusion.
The O2 sensor has nothing to do with this...
#5
Well im sure if the dealer said that you need a new block and or heads that they performed either a compression test or leakdown test to see if any of the cylinders are bad or vehicle has bent valves. Missfires can be caused by several things, its just a matter of some diag to figure it out, if the car has only 12k miles then this should be covered under warranty. As long as they cant prove that the engine was damaged by a misshift or abuse.
#7
i just found out that they did a compression test where cylinder 5 is alot lower than the other cylinders 110 to 120 and the others where 170 to 180. the day it started i kick it i was in 3 and i shifted to 2 where i had to go in 4 and the rpm shot up when i got to where i was going it started to run funny. I told my budy that i mess up on my shifting and he said that it should have nothing to do with that. the dealer saidthat something is bent in cylinder 5.
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#8
Originally Posted by jon34
the day it started i kick it i was in 3 and i shifted to 2 where i had to go in 4 and the rpm shot up when i got to where i was going it started to run funny. I told my budy that i mess up on my shifting and he said that it should have nothing to do with that. the dealer saidthat something is bent in cylinder 5.
#9
Originally Posted by jon34
i just found out that they did a compression test where cylinder 5 is alot lower than the other cylinders 110 to 120 and the others where 170 to 180. the day it started i kick it i was in 3 and i shifted to 2 where i had to go in 4 and the rpm shot up when i got to where i was going it started to run funny. I told my budy that i mess up on my shifting and he said that it should have nothing to do with that. the dealer saidthat something is bent in cylinder 5.
You'll need to have that fixed.
Obviously it's not an O2 sensor...
Your buddy has no idea what kind of revs were involved when you accidentally hit 3nd gear, so his opinion doesn't really mean a whole lot.
A quick 10K rpm spike will fry the engine.
And chances are the damage isn't limited to cylinder 5.
#10
I always love it when the vital detail finally comes out-
Was looking for 4th gear when I found 2nd and the redline was exceeded by a LOT
The engine probably went into safe- limp mode to get you off the road and to the dealer
OK so what happened is you over revved the engine and bent a valve when it hit the top of the piston- at the very least- on number 5
Until they take the top of the engine apart to get to it- there is no telling for sure what happened beyond that like camshaft damage and piston damage and other cylinders may be in danger too
I thought all our cars have a rev limiter? Not on the MT cars?
What did they say about warranty-? you could be looking at 4-5 gs depending- or 1500
Was looking for 4th gear when I found 2nd and the redline was exceeded by a LOT
The engine probably went into safe- limp mode to get you off the road and to the dealer
OK so what happened is you over revved the engine and bent a valve when it hit the top of the piston- at the very least- on number 5
Until they take the top of the engine apart to get to it- there is no telling for sure what happened beyond that like camshaft damage and piston damage and other cylinders may be in danger too
I thought all our cars have a rev limiter? Not on the MT cars?
What did they say about warranty-? you could be looking at 4-5 gs depending- or 1500
#11
NOTE:
A redline shift from 3rd to 2nd gear in a 6 speed TL will result in roughly 10,000 RPM...!!!
That's enough to fry the engine - instantly.
Rev limiters don't work with manuals when downshifting. They only work when shiting up by limiting RPMS.
The revs you get when you downshift are dictated solely by the gear ratios and vehicle speed.
He likely saw something very close to 10,000 RPM when that happened, since 3rd's ratio is 1.7:1 while 2nd's is 2.478. That's a factor of 1.46. (6,800 RPM in 3rd will equal 6,800 RPM X 1.46 (9,900 RPM) in 2nd for the same vehicle speed).
A redline shift from 3rd to 2nd gear in a 6 speed TL will result in roughly 10,000 RPM...!!!
That's enough to fry the engine - instantly.
Rev limiters don't work with manuals when downshifting. They only work when shiting up by limiting RPMS.
The revs you get when you downshift are dictated solely by the gear ratios and vehicle speed.
He likely saw something very close to 10,000 RPM when that happened, since 3rd's ratio is 1.7:1 while 2nd's is 2.478. That's a factor of 1.46. (6,800 RPM in 3rd will equal 6,800 RPM X 1.46 (9,900 RPM) in 2nd for the same vehicle speed).
#13
today i found out that it is not only cylinder 5 there is 3 cylinders with low compression. tommorrow i am going to get a quote to fix it and i hope its going to fix it.
thank guys i'll keep you posted on what happenes.
thank guys i'll keep you posted on what happenes.
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