BoostinZ28

ok well we got the motor dropped in and running and everything runs great when you first crank it up id idles perfect and i cant tell you how much i love the sound of that 306 cam but after you drive it for a bit and it warms up it wont idle for nothing. It will go down to bout 500-600 rpms then id just sputters out. Any ideas? Its a 95 z28 with a fresh 383. I had CSS send me a mail order tune for it. Im running accel 30lb injectors that have sat for a bit but seem to be doing fine. Also im hoping theyre 30lb cause they have a little 30 stamped on the top. I have a 58 mm bbk/edelbrock throttle body. Oh and another thing is it sucks air like crazy. You can be standing like 20 ft from the car while its idleing and all you can hear is it pulling in air is this normal. i just have a aluminum intake tube with a k&n cone filter but its crazy loud.

BoostinZ28

ok someone must at least have a suggestion lol

Mike96z

The sucking sound is normal, the throttle body is high flow and that 383 is surely sucking alot of air. As for when It gets warm and not wanting to idle correctly, do you have any codes being thrown? Also do you have ported/polished heads? If you do, why did you go with such a mild cam, to a stock engine the 306 is big, but on a 383 its not. Do you still have CATS etc?

gpss97

what is your idle set at? mine was set to idle and 900 and it did the same thing...so i put it back up to 1k-1100 and it drives fine..don't know if that was the problem or just covered it up or what.

BoostinZ28

yes the head and intake are ported and when me and my dad were building it i had a hard time explaining about the cam being somewhat mild for the build. Hes an oldschool chevy guy. But anyways no codes at all and i we removed the egr/air system completely and i still have the stock y-pipe but i think the previous owner had a hi-flow cat welded in cause its just a straight through design with some baffling around the shell of the cat. But im bout to call CSS and ask if they have any ideas. thanks

Mike96z

talk to your tuner, seems like they didnt disable the emissions and rear o2s in the PCM or something. I know that without the heated cats or o2 that the engine will run ****ty til it warms up but never heard of it running ****ty after it warms up. Unless the tune has something to do with it.

Denny McLain

Sounds like a vacuum leak and the computer is trying to learn. The computer will do its best to compensate but both vacuum and exhaust leaks raises hell with 02 controlled computer cars.

Iron your bugs out and you'll be OK. Just new setup blues.

SS RRR

It sounds like something is obstructing your intake plumbing. Shouldn't be that loud.

BoostinZ28

Well im starting to think its got to do with my injectors because after you go past half throttle it starts sputtering and acting like its just falling on its face. IM running 30lb accels that have been sitting for a little while so i guess that might be the problem.

dangalla

could be something to do with the car going into closed loop, bad sensor somewhere or something, i would check it for codes then find someone with a scantool (local shop or something) and monitor the pids when you first start the car and again when it gets warm and note any differences or abnormal readings, would start by looking at o2 b1s1 b2s1, maf, ect, oh and look at your stft and ltft and note any differences between banks, and make sure the pcm is not pulling timeing due to knock(383 with a cam even if mild could make a knock sensor go crazy)

BoostinZ28

well i hooked up a scantool but no cel was on so it didnt pul any codes. but if it was knock an lt4 module would correct it right?