Poping sound?
 

Just took the civic for a drive for the first time. Boost comes on at like 3000rpm or abit less.

Only problems are when it idles , it makes a poping sound from the exhaust.. Only thing i can think of is to check the timing which ill do asap.

Other thing is at bout 5000rpm, itll start to missfire etc.. VTEC isnt engaged yet so its nothin to do with that.

Only thing i come up with is
A) The tune itself (xerocens tune)
b) Timing is way out?

Anyone got any suggestions?

Thanks

Re:Poping sound?
 

try gapping your plugs around 30 or even lower 25.. we had that problem on both of my friends cars until we did that.. and it also stoped poping if we added lots of timing.

Re:Poping sound?
 

30??

.30mm's?? :o

Is that what you mean?

Re:Poping sound?
 

.30 inches...that's about exactly 0.762mm

Re:Poping sound?
 

the pooping is a side effect of the big injectors and retarded timing.

Re:Poping sound?
 

Ok.. so its not actually doing the engine any harm is it?

Re:Poping sound?
 

No, but it's sometimes annoying when you just want to drive easy and not atract attention from the cops when running only with the downpipe ::)

Re:Poping sound?
 

can someone describe this popping sound a little bit more.. is it a backfire sound?

Re:Poping sound?
 

Ill try get a recording of it.

But yeh, it is sorta like a back fire, but the engine revs dont really get effected by it.. It does it all the time.. Im trying a couple of new maps, as the current one makes the car run like ----.

Re:Poping sound?
 

It is a backfire sound....it doesn't sound really loud, you hear it alot when slow down or when you down shift and slow down....when I downshift and slow down I would get a real backfire and flames would shoot out my downpipe ;D....At night it looks like a fireworks show ;D

Re:Poping sound?
 

that's just not good.. yeah sometimes it's cool to have a car that shoots flames, otherwise it's not the most "efficient" thing to do.

Re:Poping sound?
 

its more like a "bubbling sound" right? its cause yah got too much gas and too much spark.

Re:Poping sound?
 

yeh, you could say it bubbling.. Im trying some new chips.. If it doesnt help, im guna use aftermarket ecu ???

Re:Poping sound?
 

1/3 of an inch is .762mm huh :)

Re:Poping sound?
 

1/3 of an inch is 0.333333333 inches that's more then 0.762mm

Re:Poping sound?
 

i think your running a little rich at idle

Re:Poping sound?
 

Ok lets try this. 1 inch=2.4cm=24mm .30inch would be 7.2mm.
Thought I might help you guys out here.

Re:Poping sound?
 

actually 1 inch = 2.54 cm to be exact

.3 inches = .762 cm
1/3 inch = .847 (round up) cm

Re:Poping sound?
 

I can't believe I forgot my 5 in that. 2.54cm in an inch is right sorry bout that

Re:Poping sound?
 

there is no such thing as a centimetre it is a unit made up so preschool kids can measure ---- without the numbers getting too big for them. I think what is meant is gap the plugs to 0.030"

Re:Poping sound?
 

ding ding ding, i think we have a winner

and i agree .030 is a good place to start, if the issue persists, try making the gap a little smaller.

Re:Poping sound?
 

this isn't a metric conversion thread ::)

So is this sound that everyone is talking about like the motor is still running after ignition is shut off? I had a bad centre shaft in my factory 4 barrel carb and it would always idle at 1.5k rpms. When I shut it off it would shut down, then make a noise like the motor was still running for a couple of seconds.

Needless to say I swapped that bitch out for a edelbrock 1400 series.

Re:Poping sound?
 

I was about to say what the ----?

Re:Poping sound?
 

Right... the poping sound was actually the rebound of the sound off the concrete under the car as the downpipe aimed straight down..

The cars running mint at the moment, 4psi and no vtec... ith the VTEC part, i just tried to make a switch of the 12v to the ecu and to the VTEC wire. It didnt work tho.. would that be because i used 12v goin to the ecu... should i use it somewhere else.. it definatly does something, but just sounds like its sorta missfiring.. i did do it when i was driving the car as well.

Thanks guys! Ill post some pics of the whole conversion soon ;D

Re:Poping sound?
 

Our 400sbc sometimes dieseled for a couple seconds after the ignition was shut off, when it was still running a quadrajet.