Misfire codes..
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From: san francisco
Misfire codes..
so recently i had a older post about this but i couldnt find it who knows why. but i got my valve adjustment timing belt water pump done because i have been reading a lot and people said get valve adjustment . so i did codes didnt come back for another approx 1k-2k miles . then recently i have been getting the codes again. i called acura baout the bulletin about random misfire codes and getting a ecu reflash. i called and the guy told me he has NEVER heard of a ecu reflash solving the problem of random misfire codes.. so now im back to square one. i ahve changed all 6 spark plugs. valve adjustment. timing belt. water pump. my coilpacks were told to me that they looked good so i didnt want to change them. as i was reading more there have been many post about mis shift and bent valves. if i were to pull off the head to look what am i looking for ? how do i pull out the heads? please help!
You put no info about your car. How many miles, mods or no? You can't look at a coilpack and tell if it's good or not. Could be so many different things or combination of things causing this. Too rich, too lean, bad coil(s), injectors(s), etc. Did you mis shift? It's probly unlikely that you bent a valve. Unfortunately there is no easy answer.
Thread Starter
Banned
Joined: Jul 2011
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From: san francisco
You put no info about your car. How many miles, mods or no? You can't look at a coilpack and tell if it's good or not. Could be so many different things or combination of things causing this. Too rich, too lean, bad coil(s), injectors(s), etc. Did you mis shift? It's probly unlikely that you bent a valve. Unfortunately there is no easy answer.
2004 acura tl manual base
appox 89k miles
i havent mis shifted
mods are only cat back exhaust p2r throttle body spacer fujita cai
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-------Tim-------
Joined: Mar 2010
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From: Tampa, Fl
^it could be a number of different things. I would ask them to look up the vin#, to see if it ever has had the ecu reflash. I am not sure if the MT '04, was on the tsb for the ecu reflash. I have an '04 AT, and had the random misfires. It took 3 attempts at the dealer, before they performed the reflash (for $50), since then no more misfires. Good luck!
Thread Starter
Banned
Joined: Jul 2011
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From: san francisco
sorry if im reviving a dead thread.
but my misfire came back again after a while... so my question is what are all contributing factors of misfire? so i can diagnose each one
spark plugs
coils
coil lines
fuel injectors
fuel pump
crank position sensor
what else is there?
how can i diagnose each problem?
and recently i noticed it might be an electrical issue?
when i roll up the windows all teh way up and i click up again i would hear a surge in my exhaust
when i tilt my wheel a little bit at idle the exhaust woudl surge
when i turn on my ac or turn on the heater my exhaust would surge and i would hear my exhaust a little bit then go back down.
thanks!
but my misfire came back again after a while... so my question is what are all contributing factors of misfire? so i can diagnose each one
spark plugs
coils
coil lines
fuel injectors
fuel pump
crank position sensor
what else is there?
how can i diagnose each problem?
and recently i noticed it might be an electrical issue?
when i roll up the windows all teh way up and i click up again i would hear a surge in my exhaust
when i tilt my wheel a little bit at idle the exhaust woudl surge
when i turn on my ac or turn on the heater my exhaust would surge and i would hear my exhaust a little bit then go back down.
thanks!
Pro
Joined: May 2009
Posts: 560
Likes: 37
Your exhaust valves are probably bent
All those things you did that caused a "surge" are things that put a load on your engine. Electrical items will put a load on your engine through the alternator. Your steering wheel will put a load on your engine through the power steering pump. Your AC will put a load on your engine through the compressor. When a load is put on your engine, it takes it a second to readjust.
Your whole thing sounds a lot like bent valves to me. Have you had a compression test done? A leak-down test? They can pull the valve covers to check the clearance between the valves and the rockers (if it's too loose, the valve might be stuck open).
Are you the original owner? I'm going through something like this right now. I need to pass the emissions inspection, so I need a diagnosis to get a waiver. There's no way I'm paying $4000 to have my valves replaced only to have them get messed up again later. I accidentally overreved it again not too long ago. This engineering flaw really upsets me.
Your whole thing sounds a lot like bent valves to me. Have you had a compression test done? A leak-down test? They can pull the valve covers to check the clearance between the valves and the rockers (if it's too loose, the valve might be stuck open).
Are you the original owner? I'm going through something like this right now. I need to pass the emissions inspection, so I need a diagnosis to get a waiver. There's no way I'm paying $4000 to have my valves replaced only to have them get messed up again later. I accidentally overreved it again not too long ago. This engineering flaw really upsets me.
sorry if im reviving a dead thread.
but my misfire came back again after a while... so my question is what are all contributing factors of misfire? so i can diagnose each one
spark plugs
coils
coil lines
fuel injectors
fuel pump
crank position sensor
what else is there?
how can i diagnose each problem?
and recently i noticed it might be an electrical issue?
when i roll up the windows all teh way up and i click up again i would hear a surge in my exhaust
when i tilt my wheel a little bit at idle the exhaust woudl surge
when i turn on my ac or turn on the heater my exhaust would surge and i would hear my exhaust a little bit then go back down.
thanks!
but my misfire came back again after a while... so my question is what are all contributing factors of misfire? so i can diagnose each one
spark plugs
coils
coil lines
fuel injectors
fuel pump
crank position sensor
what else is there?
how can i diagnose each problem?
and recently i noticed it might be an electrical issue?
when i roll up the windows all teh way up and i click up again i would hear a surge in my exhaust
when i tilt my wheel a little bit at idle the exhaust woudl surge
when i turn on my ac or turn on the heater my exhaust would surge and i would hear my exhaust a little bit then go back down.
thanks!
Thread Starter
Banned
Joined: Jul 2011
Posts: 444
Likes: 35
From: san francisco
All those things you did that caused a "surge" are things that put a load on your engine. Electrical items will put a load on your engine through the alternator. Your steering wheel will put a load on your engine through the power steering pump. Your AC will put a load on your engine through the compressor. When a load is put on your engine, it takes it a second to readjust.
Your whole thing sounds a lot like bent valves to me. Have you had a compression test done? A leak-down test? They can pull the valve covers to check the clearance between the valves and the rockers (if it's too loose, the valve might be stuck open).
Are you the original owner? I'm going through something like this right now. I need to pass the emissions inspection, so I need a diagnosis to get a waiver. There's no way I'm paying $4000 to have my valves replaced only to have them get messed up again later. I accidentally overreved it again not too long ago. This engineering flaw really upsets me.
Your whole thing sounds a lot like bent valves to me. Have you had a compression test done? A leak-down test? They can pull the valve covers to check the clearance between the valves and the rockers (if it's too loose, the valve might be stuck open).
Are you the original owner? I'm going through something like this right now. I need to pass the emissions inspection, so I need a diagnosis to get a waiver. There's no way I'm paying $4000 to have my valves replaced only to have them get messed up again later. I accidentally overreved it again not too long ago. This engineering flaw really upsets me.
1 cylinder was like 100 off from teh others so im going to get anotehr compression test soon.
no leaks
Advanced
Joined: Aug 2011
Posts: 75
Likes: 24
From: Monroe, Ohio
Who performed the work on your car? Dealer? Shadeshop?
Their are 2 major types of misfires.
1. Electrical misfires(coils, wiring, ecm/pcm)
2. Mechanical misses (plugs, improper valve clearance,etc)
If somone went to loose or to tight on the valve adjsutment that could cause your miss.
The best way to determine which type of misfire your dealing with is to graph the map sensor voltage(min .80v max1.0v) if the graph looks like a square wave it's electrical in nature. if the graph looks like a lie detector graph(best description) it's mechanical. the only issue is having the right hardware to perform this type of troubleshooting. HDS tablet, MVCI interface etc.
not everyone has this capability but this info will help when you at the dealership. ask these type of questions. unfortunatly good diagnostic technicians are hard to find and keep in a store. Part hangers run rampant. they see P0301-P0306 and assume plugs, maybe a coil, and just start replacing items until its resolved without knowing the root cause. which gives dealerships the "stealership" name. and makes it hard for us properly trained techs.
I hope some of this info helps in your search for the answer. I would def have another compression test done. those results seem a tad lop-sided. you should be experiencing other issues with results like that.
Cheers!
Their are 2 major types of misfires.
1. Electrical misfires(coils, wiring, ecm/pcm)
2. Mechanical misses (plugs, improper valve clearance,etc)
If somone went to loose or to tight on the valve adjsutment that could cause your miss.
The best way to determine which type of misfire your dealing with is to graph the map sensor voltage(min .80v max1.0v) if the graph looks like a square wave it's electrical in nature. if the graph looks like a lie detector graph(best description) it's mechanical. the only issue is having the right hardware to perform this type of troubleshooting. HDS tablet, MVCI interface etc.
not everyone has this capability but this info will help when you at the dealership. ask these type of questions. unfortunatly good diagnostic technicians are hard to find and keep in a store. Part hangers run rampant. they see P0301-P0306 and assume plugs, maybe a coil, and just start replacing items until its resolved without knowing the root cause. which gives dealerships the "stealership" name. and makes it hard for us properly trained techs.
I hope some of this info helps in your search for the answer. I would def have another compression test done. those results seem a tad lop-sided. you should be experiencing other issues with results like that.
Cheers!
Thread Starter
Banned
Joined: Jul 2011
Posts: 444
Likes: 35
From: san francisco
Who performed the work on your car? Dealer? Shadeshop?
Their are 2 major types of misfires.
1. Electrical misfires(coils, wiring, ecm/pcm)
2. Mechanical misses (plugs, improper valve clearance,etc)
If somone went to loose or to tight on the valve adjsutment that could cause your miss.
The best way to determine which type of misfire your dealing with is to graph the map sensor voltage(min .80v max1.0v) if the graph looks like a square wave it's electrical in nature. if the graph looks like a lie detector graph(best description) it's mechanical. the only issue is having the right hardware to perform this type of troubleshooting. HDS tablet, MVCI interface etc.
not everyone has this capability but this info will help when you at the dealership. ask these type of questions. unfortunatly good diagnostic technicians are hard to find and keep in a store. Part hangers run rampant. they see P0301-P0306 and assume plugs, maybe a coil, and just start replacing items until its resolved without knowing the root cause. which gives dealerships the "stealership" name. and makes it hard for us properly trained techs.
I hope some of this info helps in your search for the answer. I would def have another compression test done. those results seem a tad lop-sided. you should be experiencing other issues with results like that.
Cheers!
Their are 2 major types of misfires.
1. Electrical misfires(coils, wiring, ecm/pcm)
2. Mechanical misses (plugs, improper valve clearance,etc)
If somone went to loose or to tight on the valve adjsutment that could cause your miss.
The best way to determine which type of misfire your dealing with is to graph the map sensor voltage(min .80v max1.0v) if the graph looks like a square wave it's electrical in nature. if the graph looks like a lie detector graph(best description) it's mechanical. the only issue is having the right hardware to perform this type of troubleshooting. HDS tablet, MVCI interface etc.
not everyone has this capability but this info will help when you at the dealership. ask these type of questions. unfortunatly good diagnostic technicians are hard to find and keep in a store. Part hangers run rampant. they see P0301-P0306 and assume plugs, maybe a coil, and just start replacing items until its resolved without knowing the root cause. which gives dealerships the "stealership" name. and makes it hard for us properly trained techs.
I hope some of this info helps in your search for the answer. I would def have another compression test done. those results seem a tad lop-sided. you should be experiencing other issues with results like that.
Cheers!
mechanical is what i think it is because iknow i have over revved my car. i have had a valve adjustment done to my car because of this misfire. before this valve adjustment i wasnt able to feel or hear my vtec ingage but now i do after the adjustment.
someone told me to go get my ecu reflashed but teh dealer said they never heard about a ecu reflash fixing a random misfire code.
so im thinking get another compression test. if it does go good. remove the heads and see if i have a bent valve which im suspecting.
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