Backfiring/popping under boost
 

I have had zero time lately this semester to work on my car, but lately it has been popping at boost levels above 12 psi. If I keep the boost low it's fine. I just want to know if you guys have experienced it and what the cause was.

I'm just going to guess it's too rich due to the colder air this time of year, but who knows. I haven't even had time to hook up my wideband up and check :S

Re: Backfiring/popping under boost
 

spark blowout. put in fresh plugs gapped to .028 and see what she says.

Re: Backfiring/popping under boost
 

No, that's not it. Spark blowout would just cause misfiring, not backfiring and loud ass popping noises.

The plugs are gapped at .025"

Re: Backfiring/popping under boost
 

so when you put in fresh plugs it continues?

Re: Backfiring/popping under boost
 

cold air makes you run leaner unless you're tune is offset for it.

Re: Backfiring/popping under boost
 

Thanks captain obvious. What the hell do you mean "offset" :S

Re: Backfiring/popping under boost
 

Just thought maybe you were getting it backwards cause of this
Wouldn't the iat correction table handle this?

Re: Backfiring/popping under boost
 

make sure your map sensor is happy. Also any cel's?

Re: Backfiring/popping under boost
 

No CELs, don't think there's any problem with the map sensor...

Re: Backfiring/popping under boost
 

How old are your ignition parts cap/rotor/plugs/wires?

Re: Backfiring/popping under boost
 

if ur running a stock map sensor it wont like anything over about 11 or so pounds. thats what my crx does when it spikes over about 11 pounds

Re: Backfiring/popping under boost
 

Everything is less than 2 years old other than wires... I have another set laying around I'll give it a shot.

2.5 bar

Re: Backfiring/popping under boost
 

just a thought it wouldnt happen to be related to rpm at all would it? maybe some sort of coil breakdown or would that cause a misfire too?

Re: Backfiring/popping under boost
 

Nope, only on high boost. Lower than 12 psi she revs to 7000 just fine

Re: Backfiring/popping under boost
 

Re: Backfiring/popping under boost
 

Yep

Re: Backfiring/popping under boost
 

vids possible? i had this issue pretty bad, pulled great to redline at 17 or so, go to 22 and it would pop like mad, new plugs always pull smooth to 30...
i had to do 3 fixes
1) lean it out a tad up top, misifires at 10.8, pulls solid at 11.2
2) gap down plugs to .024ish
3) go ass to mouth on a drunken townie, then seafoam my ----

Re: Backfiring/popping under boost
 

#3 (first part) seems to be something worth trying

Re: Backfiring/popping under boost
 

sounds like the temp change is your problem to me.

are you using crome? there is a place where you can change the multipliers for different temps

Re: Backfiring/popping under boost
 

Bad coil/distributor.

Re: Backfiring/popping under boost
 

I agree on distributor :y My hatch was ------ up bout a month ago. It isnt boosted, but whenever I would go over a certain RPM , or stomp on the gas my ---- would lose power and pop loud as hell. It became hard to start as well. The car acted tempramental for bout a month, then would not even start up. I ended up replacing the dizzy (scored one for 40 bucks) and after that car ran strong with no poping / loss of power.

Re: Backfiring/popping under boost
 

Not the dizzy or anything inside it including coil, tried another one with the same results. It's not RPM related, it's related to boost levels over 12 psi.

Re: Backfiring/popping under boost
 

Im throwing out the map sensor thought again then

Re: Backfiring/popping under boost
 

my buddy had a bad map cause his car to cutout after vtec. Mabey try the battery tables cooler weather less votage battery puts out. mabey you were on the edge of 1 table and now you fallen completely into them.

Re: Backfiring/popping under boost
 

hmmm the cold weather and low battery output with the power cables would of been a combination I would of never thought up. Good ideas guys!