car STILL backfires...
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the original thread was posted on april 14,2007...when i put the b16a in there years ago i didn't have any other mods apart from the 2 1/4" catback exhaust and a K &N cold air intake. it was backfiring. now i have added 4-1 headers, a larger throttle body, and an intake manifold. No difference in backpressure. I haven't checked my ignition timing or valve lash. honestly i've never heard of a valve lash...i'm not aware of any leak in the exhaust system, manifold or intake manifold either.
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What size is the tip you are running ? and is 2 1/4" your stock size piping ?..
I would go with the advice above, timing lash and leaks, and if thats not it maybe it is the cat. There are alot of things that could contrubute to this. I know in my old LS it would backfire with a stock cat, and 2.5" piping, But I replaced the whole system back to a stock style and it got rid of it, pretty much confirming it was an air flow thing. Does your tip have a silencer ? If so, try pluggin that in and listen for it..
Ohh, when you shift, what rpm range does it do this in, or is it all ranges ?
I would go with the advice above, timing lash and leaks, and if thats not it maybe it is the cat. There are alot of things that could contrubute to this. I know in my old LS it would backfire with a stock cat, and 2.5" piping, But I replaced the whole system back to a stock style and it got rid of it, pretty much confirming it was an air flow thing. Does your tip have a silencer ? If so, try pluggin that in and listen for it..
Ohh, when you shift, what rpm range does it do this in, or is it all ranges ?
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What is stated about the PCV valve "could" be true but it is on the lower end of possibilities. To rule this out inspect the air filter and see if there is any burned out looking spots on it. That is a good sign something is wrong with the PCV valve.
Moving on. Backfiring is commonly caused by un-burnt fuel igniting from the heat of the exhaust, thus causing combustion and the backfire. With straight through exhaust it will be more noticeable as well.
1. You already replaced the cat so rule that out. Did you notice a reduction in the backfiring after doing this?
2. If the o2 sensors were bad you would throw a CEL.
3. It could still be running rich which is calling for an adjustment to the fuel supply and a tune on the timing.
4. A resonator and chambered muffler may eliminate this as well. I am saying that because when I had my greddy exahaust it was straight pipe from the cat back into a straight through muffler and it backfired like a bitch. When I switched to the Apexi WS2 it all went away.
5. Have you noticed if the exhaust tip is heavily blackened? How about the paint around the bumper.
6. For starters I would run Honda Top end cleaner though the motor to clean it out good and blow the crap out. Then go from there.
So pick your poison and think what you think it might be with the new info. provided. Everything listed is a possibility.
Moving on. Backfiring is commonly caused by un-burnt fuel igniting from the heat of the exhaust, thus causing combustion and the backfire. With straight through exhaust it will be more noticeable as well.
1. You already replaced the cat so rule that out. Did you notice a reduction in the backfiring after doing this?
2. If the o2 sensors were bad you would throw a CEL.
3. It could still be running rich which is calling for an adjustment to the fuel supply and a tune on the timing.
4. A resonator and chambered muffler may eliminate this as well. I am saying that because when I had my greddy exahaust it was straight pipe from the cat back into a straight through muffler and it backfired like a bitch. When I switched to the Apexi WS2 it all went away.
5. Have you noticed if the exhaust tip is heavily blackened? How about the paint around the bumper.
6. For starters I would run Honda Top end cleaner though the motor to clean it out good and blow the crap out. Then go from there.
So pick your poison and think what you think it might be with the new info. provided. Everything listed is a possibility.
Honda Top end cleaner. I'll try it. And maybe I'll also look into an adjustment to the fuel supply and a tune on the timing. Thanks for all the advice everyone. i hope one of these suggestions will solve the problem.
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What is stated about the PCV valve "could" be true but it is on the lower end of possibilities. To rule this out inspect the air filter and see if there is any burned out looking spots on it. That is a good sign something is wrong with the PCV valve.
Moving on. Backfiring is commonly caused by un-burnt fuel igniting from the heat of the exhaust, thus causing combustion and the backfire. With straight through exhaust it will be more noticeable as well.
1. You already replaced the cat so rule that out. Did you notice a reduction in the backfiring after doing this?
2. If the o2 sensors were bad you would throw a CEL.
3. It could still be running rich which is calling for an adjustment to the fuel supply and a tune on the timing.
4. A resonator and chambered muffler may eliminate this as well. I am saying that because when I had my greddy exahaust it was straight pipe from the cat back into a straight through muffler and it backfired like a bitch. When I switched to the Apexi WS2 it all went away.
5. Have you noticed if the exhaust tip is heavily blackened? How about the paint around the bumper.
6. For starters I would run Honda Top end cleaner though the motor to clean it out good and blow the crap out. Then go from there.
So pick your poison and think what you think it might be with the new info. provided. Everything listed is a possibility.
Moving on. Backfiring is commonly caused by un-burnt fuel igniting from the heat of the exhaust, thus causing combustion and the backfire. With straight through exhaust it will be more noticeable as well.
1. You already replaced the cat so rule that out. Did you notice a reduction in the backfiring after doing this?
2. If the o2 sensors were bad you would throw a CEL.
3. It could still be running rich which is calling for an adjustment to the fuel supply and a tune on the timing.
4. A resonator and chambered muffler may eliminate this as well. I am saying that because when I had my greddy exahaust it was straight pipe from the cat back into a straight through muffler and it backfired like a bitch. When I switched to the Apexi WS2 it all went away.
5. Have you noticed if the exhaust tip is heavily blackened? How about the paint around the bumper.
6. For starters I would run Honda Top end cleaner though the motor to clean it out good and blow the crap out. Then go from there.
So pick your poison and think what you think it might be with the new info. provided. Everything listed is a possibility.
so what does it mean if my tip is heavily blackened anyways?
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From: Irvine CA
There's going to be a degree of soot, but when it looks like the walls of a fireplace it is a clear indication that your running rich = unburnt fuel. As there is nothing visible on your paint then it is not horribly bad because that is when it really shows. Was your other paint job covered in soot?
Aside from the honda top end cleaner, people have also tried Seafoam which is less expensive. This will clean the motor out, so in case you have a heavy carbon build up, which could hinder fire power, that will eliminate most of that. The car will smoke like a bitch and that means it is working so don't shit yourself. After about 3 minutes of smoking your neighbors should be pretty pissed so go for a drive and blow that shit out. You may notice an increase in power as well, this does not mean you gained HP per se but that you have revived hp lost. so glass 1/2 empty or 1/2 full what have you.
If the backfire is still there move onto the other factors. Take note of the frequency of the backfire though. It is a process of elimination. Start w/the most affordable things first.
Aside from the honda top end cleaner, people have also tried Seafoam which is less expensive. This will clean the motor out, so in case you have a heavy carbon build up, which could hinder fire power, that will eliminate most of that. The car will smoke like a bitch and that means it is working so don't shit yourself. After about 3 minutes of smoking your neighbors should be pretty pissed so go for a drive and blow that shit out. You may notice an increase in power as well, this does not mean you gained HP per se but that you have revived hp lost. so glass 1/2 empty or 1/2 full what have you.
If the backfire is still there move onto the other factors. Take note of the frequency of the backfire though. It is a process of elimination. Start w/the most affordable things first.
Last edited by ADRONICUS; Jun 2, 2007 at 08:05 AM.
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There's going to be a degree of soot, but when it looks like the walls of a fireplace it is a clear indication that your running rich = unburnt fuel. As there is nothing visible on your paint then it is not horribly bad because that is when it really shows. Was your other paint job covered in soot?
Aside from the honda top end cleaner, people have also tried Seafoam which is less expensive. This will clean the motor out, so in case you have a heavy carbon build up, which could hinder fire power, that will eliminate most of that. The car will smoke like a bitch and that means it is working so don't shit yourself. After about 3 minutes of smoking your neighbors should be pretty pissed so go for a drive and blow that shit out. You may notice an increase in power as well, this does not mean you gained HP per se but that you have revived hp lost. so glass 1/2 empty or 1/2 full what have you.
If the backfire is still there move onto the other factors. Take note of the frequency of the backfire though. It is a process of elimination. Start w/the most affordable things first.
Aside from the honda top end cleaner, people have also tried Seafoam which is less expensive. This will clean the motor out, so in case you have a heavy carbon build up, which could hinder fire power, that will eliminate most of that. The car will smoke like a bitch and that means it is working so don't shit yourself. After about 3 minutes of smoking your neighbors should be pretty pissed so go for a drive and blow that shit out. You may notice an increase in power as well, this does not mean you gained HP per se but that you have revived hp lost. so glass 1/2 empty or 1/2 full what have you.
If the backfire is still there move onto the other factors. Take note of the frequency of the backfire though. It is a process of elimination. Start w/the most affordable things first.
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From: Irvine CA
my other paint job was not covered in soot. So in my city the automotive store is Canadian Tire. They've never heard of honda top end cleaner or Seafoam. But he said they have Lucas. Should i just use any product that will clean the motor out since i can't find the products you mentioned? The Honda dealer doesn't even carry honda top end cleaner
The honda dealer should be able to get if you request it. They may not have it but they can order it. If you want to wait then go for it. If not make sure the Lucas treatment is to clean out the carbon build up inside the motor and is fed through the intake or the fuel line.
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i'm not sure exactly what ecu im running but i do know with my original ecu vtec would kick in at 4800. now with the ecu i've had for the past few years the vtec kicks in at 5800.