ok, my friend has a jdm b16 engine, and he recently installed new cat, aem fuel rail, and skunk2 intake manifold...once he got it back from the shop and started driving it, he noticed that it would backfire everytime he revs pass 5k and releases the gas, so as the RPM would go down, it would backfire....i was told that it could be a burnt valve?? and most people just say that he's running too rich...so could i get some input here?

 

Probably running rich, but also what type of exhaust is he running? I have a 2.25 and everytime i would rev to a curtain spot i would hear echos through the exhaust and i thought i was backfiring fire but i never did Could just be echos though.

 

Could be loose timing belt and tensioner, but not pretty sure.

bump 4 u!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Emong3 &raquo;</TD></TR><TR><TD CLASS="quote">Could be loose timing belt and tensioner, but not pretty sure.

bump 4 u!</TD></TR></TABLE>

Huh?!?!

 

he has a 5zigen catback system...but it wasn't doing this when he had that exhaust, it started doing this once he had his intake manifold installed, fuel rail, and cat...can someone verify if it can be a burnt valve or not??

 

 

i doubt its a burnt valve.. is it a high flow cat.. i have no cat or anything jdm type r header 2.25 exhaust with resenator. and if i rev high and i let off or shift high but not beating on it it will pop a little its just a lot of flow going through there .. as long as there are no flames or anything id say hes straight. is it still running good?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdm4dr &raquo;</TD></TR><TR><TD CLASS="quote">i doubt its a burnt valve.. is it a high flow cat.. i have no cat or anything jdm type r header 2.25 exhaust with resenator. and if i rev high and i let of or shift hight but not beating on it it will pop a little its just a lot of flow going through there .. as long as there are no flames or anything id say hes straight. is it still running good?</TD></TR></TABLE>
my gsr does the same thing i got 2.25" piping with a test pipe.

 

I get kinda a popping when I left off the gas. I running a high flow cat right off the stock manifold with 2.25 piping to a ES Oval. Im not sure what causing it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdm4dr &raquo;</TD></TR><TR><TD CLASS="quote">is it still running good?</TD></TR></TABLE>

yeah, it's running ok...he has an OBX high flow cat...could he be losing power from this though?? it pops about 3-4 times when he lets off the gas pedal...but how do we fix this?? he is getting a fuel pressure regulator soon, and maybe that could fix the problem, IF he's running too rich? but could this harm the engine at all?

 

its just no back pressure that makes it pop. it pops as you rev down .. like if you get the rpms up and keep it in gear and let them drop .you will get better top end pull but your bottom end wont be as good with no cat/ high flow cat IMHO.

 

could the backfire eventually harm the engine in any way? because he wants to race it tomorrow night, but he's all paraniod that his engine might blow up or something.

 

from what it sounds like its not back fireing its just popping. back fireing is when its running really rich and when it ignites the excess fuel and a flame shoots out for the most part.. im just guessing though. id have to hear it.

 

I've got a Skunk2 catback, Greddy header, test pipe, and my car backfires/gurgles quite a bit. It never did it at all with the stock exhaust. I personally think it sounds kinda cool, but it's due to the high flow nature of the exhaust.

 

yeah, but doesn't that annoy you?? lol...your just driving normal, and you reach a stop light, so you put it in neutral, and then *POP POP POP*! lol...oh well, as long as it doesn't harm the engine or anything, i'm sure he won't mind

 

This sounds odd. What ECU are you running? Chipped? JDM? JDM B16 2nd gen ECU's do pop when the throttle is released. But Not like you described.
The Exhaust and intake that were installed would have leaned out the mixture. The Fuel rail would have made more fuel available for the injectors. I don't see this stuff causing any problems. What other mods have been done? Turbo, nitrous? More info is needed.

 

he has a B16 sir-1. all he has right now is AEM fuel rail, skunk2 intake manifold, high flow cat, 5zigen catback system, and headers...that's about it...but this didn't start happening until he installed the fuel rail, intake manifold, and high flow cat

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by goodfella732 &raquo;</TD></TR><TR><TD CLASS="quote">I get kinda a popping when I left off the gas. I running a high flow cat right off the stock manifold with 2.25 piping to a ES Oval. Im not sure what causing it. </TD></TR></TABLE>

im running an es oval and it does the same thing...i pretty sure its supposed to do that

 

It seems like your car is just running rich i had a probe gt it run rich with exhaust and fuel upgrades when i got in to it and let out it would shoot a big blue flame out the back but it started doing that when i took the cat off get a air fuel meter see if it is just rich

 

are you sure that it only happens after 5k?....does vtec enguage ok? sounds like it is just gettting a lil bit more fuel burning off...but i could be wrong