PDA

View Full Version : What's going on with the car? Boost and Air Fuel bouncing


11Past9
01-21-2010, 07:35 PM
So I took the car out tonight to run it a bit, roads were dry and I said what the hell.

-Idle is good. And when I am boosting (not foot to the floor full boost) it's smooth.

-When I shift I'm getting a little pop of backfire from the exhaust (isn't that an indicator youre running lean?)

-Full boost, foot to the floor in 2nd or 3rd however the boost is bouncing, as is the air fuel.

It sounds like this: (forgive me for trying to type out the sound)

-Normal = vrooooooooooom psh

-it's doing = vrooooom (til full boost) then it's bouncing between 10-15 psi, the needle is just bouncing between the to and it's "vroom vrooom vrooom" like a hesitation. The air fuel is bouncing too from 10.8-12.2

Once I let off, it runs fine and boosts fine until I actually floor it.

Engine: sr20 blacktop w stock t28

Mods: fmic, exhaust, downpipe, 740cc injectors, z32 mass air flow sensor, hks evc II, aem wideband, walbro 255 fuel pump, koyo radiator.

Now the previous owner said that the EVC II has settings so it won't overboost, hit fuel cut or damage anything.

My guess: too cold out for the boost it was set on, I don't think a boost leak because it would spike and then drop not bounce.

Can someone help me out?

godrifttoday
01-21-2010, 07:49 PM
Check ur plugs

11Past9
01-21-2010, 07:54 PM
Check ur plugs

Because of the sputtering at full boost? Would that affect my air fuel though?

I hope I didn't damage anything.

LayNLow
01-21-2010, 07:58 PM
Yeah, I agree. Check plug gap.

11Past9
01-21-2010, 08:05 PM
Yeah, I agree. Check plug gap.

So am I just looking for a burnt plug?

godrifttoday
01-21-2010, 08:19 PM
When I had my 400hp civic I would change plugs about once a month, if it had a yellow thing around the white part of the plug I knew it was time to change, but also check it plug gap re-gap them

11Past9
01-21-2010, 08:53 PM
It's not just sputtering. Or hesitating. It's almost enough of a feeling as if it's kind of jerking as if I was letting of the throttle getting back on it letting off it etc

while still accellerating and only at wot. The air fuel was bouncing from 10.8 to 12.2 and the boost needle was bouncing between 10 and 15 psi but everything was smooth and good at partial boost and spirited around town driving

LayNLow
01-22-2010, 12:13 AM
Check your plug gap. Is its too much of a gap the spark will get blown out and it will almost feel like hitting the rev limiter.

11Past9
01-22-2010, 05:22 AM
That's almost what it feels like. Except not as fast as a rev limiter bounce. Should I replace all of the plugs?

j20accord00
01-22-2010, 07:22 AM
i would, its cheap enough. I used to change my plugs every other oil change when i had my sr, im doing the same with my ka-t.

its easy and cheap enough.

11Past9
01-22-2010, 03:45 PM
What should I gap the plugs to?

cotbu
01-22-2010, 05:37 PM
We usually stop spoonfeeding when the bib is cover with food!
The keep feeding me button is labeled Search