KA24DE popcorn(bone stock)

[KoukiMonsta]

okay guys this has been pissing me off for so long now. I am getting "popcorn" sound around 1800rpm while decelerating. i know this is popular w/ exhaust and all but i have a bone stock KA.(s13 ka in my s14)

i have checked

plugs
FPR
injectors
senors

thinking something was causing me to run rich. i also should get a few more MPG's but what is causing this? too much fuel being sent in or not burning all of it off?(plugs/wires kinda issue) i have no emissions stuff or IAT sensor and always have CEL for em...

[Sam_Well.13]

do a full tune up... maybe the could help...

[modulation]

At this point it could be alot of things:

1. Coolant temp sensor (goes bad, ecu thinks it's colder then it is and injects too much fuel.) Any problems starting when the engine is warm or cold?
2. O2 sensor is bad, it would really smell at idle though.
3. Vacuum leak ? (I would think it would run lean not rich which would cause the pop, but I guess it depends where it is.
4. Leaking injector..

[S14DB]

You are running deleted emissions on a OBD-II ECU?

[KoukiMonsta]

At this point it could be alot of things:

1. Coolant temp sensor (goes bad, ecu thinks it's colder then it is and injects too much fuel.) Any problems starting when the engine is warm or cold?
2. O2 sensor is bad, it would really smell at idle though.
3. Vacuum leak ? (I would think it would run lean not rich which would cause the pop, but I guess it depends where it is.
4. Leaking injector..

coolant temp sensor has been replaced.
o2 is good(i only have pre cat)
no vac leak, it idles perfect.
i checked injectors/o-rings

You are running deleted emissions on a OBD-II ECU?

yes. i have scanned it at autozone a few times, IATS is the only one that stays, others come and go, but i dont have the IAT sensor at all...

[modulation]

I should have read your full post. You don't have a "stock" 240sx when you removed emissions.

That is most likely the cause of your popping.

[240sx123$]

I have a bone stock KA too and get the same thing. On decel its like

vrrrmmmmmmmmpapapapmmmmmmmpoppop*downshift*vrrooom mmmmmpapapammmm

Mine has always done this, even with stock exhaust. Just more noticable with a catback, which is literally my only engine mod.

[jorge1190]

Im running no emissions on an OBD2 ECU also. My car also backfires, anything from "popcorn" sounds to really loud backfires, around the same RPM and runs a little rich.

[hOngsterr]

i think the popcorn noise is common in KA's

my friends was bone stock and when he went straight pipe it popped

[KoukiMonsta]

hmmm, intersting. thanks for the input guys