Intake backfiring?

[02NJHondaep3]

My AEM CAI does that. It sounds cool. again i have no technical information to answer this.

[savesteve]

If I had to venture a guess I would say it's off backpressure created in the aftermarket Tubes. Much like exhaust but the opposite. IE.The air your pulling in the tube has "spooled" (this is partly what I would asume cause SRI to have better pedal response then CAI since they have less volume to fill) to a certian pressure inside the tube, You suddenly or mildly let off the gas and the built up pressure has nowhere to go really so you get the pop when it fights it's way back out the filter? Again this is just a guess as I'm still learning about cars with my EP being the only one I've ever had worth owning.I don't think my AEM CAI has done it yet but I only hae 4500 miles on it so far. Any thoughts guys?

[Blazzik]

sounds good, sounds like that could be the culprit, anyhow, i dont think ots damaging at all, although it sounds kinda phishy

[G-J]

Weird... I have an AEM CAI and the exhaust backfires on occasions, but I havent heard the intake do it yet. But now that I said that you know damn well its gonna happen on the way home after work :D

[glw]

i've always been told that intake or exhaust backfiring is caused by a advanced or retarded ignition timing. basically an explosion is happening outside of the closed cylinders -- ex. while a intake or exhaust valve is open...

don't know how to fix it because ours is controlled by our computers... maybe someone else knows that part!

[rs_1101]

this is my theory:
most of you know from the sticky in this forum (helpful k20a info) that our cars have a total valve overlap time, where intake and exhaust valves are open at the same time, to help emissions, by using exhaust backpressure to recirculate exhaust for a partial re burn. my theory is that when decelerating or whatever the vtc and vtec dont adjust soon enough, and the rich mixture caused by a high flow intake is detonated during the overlap stage. thats why it only occurs during deceleration, and during other times of sudden change in motor rpm/output...

comments?

[Blazzik]

sounds right to me... the vtc does have somewhat of a delay so that could definately be a possiblity

[simann]

my friend has a grand national (turbo 3.8 liter v6) he has no bov so under deceleration, a bunch of air gets caught in the intake tube, it makes a loud snorkal sound similar to the backfire... ;)

[Vertigo]

Originally posted by rs_1101
this is my theory:
most of you know from the sticky in this forum (helpful k20a info) that our cars have a total valve overlap time, where intake and exhaust valves are open at the same time, to help emissions, by using exhaust backpressure to recirculate exhaust for a partial re burn. my theory is that when decelerating or whatever the vtc and vtec dont adjust soon enough, and the rich mixture caused by a high flow intake is detonated during the overlap stage. thats why it only occurs during deceleration, and during other times of sudden change in motor rpm/output...

comments?

Overlap or more commonly known as "scavenging" helps the combustion chamber rid all of the sent exhaust. In order to do this, alot of things have to happen. "Scavenging" is totally dependent on proper timing of the opening of the intake valve and the closing of the exhaust valve. If the intake is opened too soon you get too much exhaust gas pulsing into the intake tract. The intake manifold has a much lower pressure than the cylinder at this point. You'll always get some exhaust gas if you have overlap, but too much hurt engine performance. If too much exhaust gas gets into the intake, it contaminates the intake charge. Because of the scavenging effect, most of the contaminated intake air is drawn through the cylinder and out the exhaust as it should be. If you have too much scavenging, a lot of the intake charge air will rush through the cylinder and out the exhaust, creating a lean condition. The efficiency of the scavenging effect rises with engine rpm.

[sleepin02si]

I also have the same issue. I am calling Honda on Monday morning to schedule a visit. This is what I am going to tell the about:

(from another forum site)
"Just a note....

Went in for some warenty issues yesterday as I discussed. And suprise, suprise, I now have a software update for my ECU. The software flash is referenced under a Bulletin for misfire diagnostics after start up. So a Tech might not think it relevent... so ask them to look for SW updates that referance this. Somtimes manufacturers will correct multiple issues with an update but only referance 1 issue in the bullitin(Legalities).
I have put on about 400 KM since the update. and cannot reproduce the occilating tourque we were feeling... i belive the misfire diagnostics was to radical and was effecting timming causing the surges in torque. My kudos to Rob Walker and Maxwell Anderson @ Barrie Honda for there efficiency and help with my problems."

Hopefully this takes care of it.

[k20beast]

i get that same noise and it kinda pisses me off. cuz everytime it happens it sounds like something fell off. but when my exhaust does it that sounds cool. btw for my intake i just replaced my whole airbox with a cone filter.

[STP03BlueSI]

Well i had my Injen SRI back fire last week. Scared the living piss out of me and my buddy. I was doin alittle burn out. got it squeelin, and then shifted then BAM! i think i had some condensation in the intake, it was really humid that evening.

[slc71]

I have an Injen SRI also and this has not happened to me yet. Maybe I will be a lucky one. :D

[aerial]

same thing has happened to me twice when i had my AEM CAI and it just happened today with my Injen SRI. I dont hear this often, in about 3 months i heard it about 2-3 times. At the beginning i didnt know if it was my exaust or my headers. But now since im reading about this problem now im pretty sure its coming from my intake . The sound comes right from the engine and this scares the shit out of me too. I think we should get together and find out what is causing this poroblem and if this would hurt our engines. This is happening to a lot of us.

[STP03BlueSI]

I have an appointment with Honda on monday i will address this issue with them. Maybe my ECU needs that update?