i have searched and usually its from a pretty severe vacuum leak, but have a few questions.....sorry its long and descriptive

2000 camaro, stock bottom end, cam in the upper 230s, ls6 intake, old dynatech headers into a 3 inch y, 4 inch single dumped. 241 heads. that was the old setup. stock maf

new setup is the same as above, but now a fast 90, nick williams tb, 36lb densos, ported 799s. the tuner redid the tune to a basically a mail order to get it it running.

so i have done 3 8 mile trips keeping the rpms under 2500, all do ok. the car likes to stop taking throttle and u have to let off and get back on it to fix this. surging is decent for a base tune. idled around 950 and stays very steady. doesn't go up or down. occasionally the idles like to hang for a little just before i completely stopped. id like to say since it idles fine i have no leaks. didn't notice headers glowing cause i always drove in daylight. now heres where it changes

i just got done taking it to the shop to get inspected tomorrow. its nighttime. in order to pass inspection, i have to remove the 4 inch muffler, and add my cheater exhaust which goes from a 4 inch to a 2.5 inch, then into a 2.5 inch dynomax buller muffler. so obviously we are semi restricted. that was the only change i made. when i started the car it idled at 1200. then i begin driving and the car starts driving itself. if i push in the clutch while moving the rpms stay right below 2000. when i approach to a stop it idles at 2000, but a simple tap of the throttle and it slowly returns to 950 and idles perfect after about 8-10 seconds. i drove the 3.5 miles on the highway at around 60 mph. then drove 1.5 miles and hit 2 redlights on a 35 mph road. i get to the shop and pop the hood with the car running . im like man it feels hot. i look and the headers on both sides cylinders 5,6,7,8 are a tad orange/pinkish. very faint but can be seen. the light was kinda on the front 4 cylinders so its tough to tell if those we colored as well. my dummy coolant gauge was a hair above 210, its usually a needle width below 210.

could it be a combo of terrible exhaust flow and the shitty base tune? i torqued the intake like u would heads, from inside to out in like 6 different passes until it started taking some effort with the 1/4 inch drive. i used new gaskets, the map i used a new grommet, and slapped a ton of black rtv. its pretty good with minimal flex. i will put new exhaust on tomorrow after inspection, and put the correct exhaust on and redrive it but what thoughts do you guys have?

 

removed....

 

non milled. fit like a glove just about. did u et a chance to read the whole thread? it hung up very very little with the good flowing exhaust and had virtually no idling issues.

 

id really like to say that my intake is sealed good. not certain tho obviously. it should be good and tight. i heard no cracks when tightening, used the correct valley bolts, and used really fat new fast gaskets. today i will try spraying carb cleaner around it and report back.

 

I have also seen low timing cause this. For example your base idle spark might be 22 degrees, but your idle speed is high. ECM will cut spark to bring idle down. So if your ECM is cutting spark back to say 8 degrees, and its just sitting there, it would cause red headers.

That your exhaust change seems to have induced high idle speed, I can see this being the cause.

 

Also keep in mind the tb screw could be a hair off I didn' wanna mess with it until the tuner had it. I' like to say it's a combo of the weak tune and the restrictive exhaust acting like semi clogged cats stressin the car out

 

The car Def still wants to idle tho and once it gets there it' fine that' why I'd like to rule out a leak but won't know until tonight when I swap exhausts and I report back

 

picked car up. idle went straight to 2000. the whole way home i couldn't get the revs down. i pulled in the garage and they finally went down. so tonight i got the 4 inch muffler back on, double checked the intake bolts since the have been heated a few times. a few got an extra 1/4 turn. started back up went straight to 1900. i sprayed carb cleaner under intake, and all along the sides and didn't get anything noticeable. also tried the pcv lines and got nothing. brake booster good. so frustrated i started pulling sensors. maf changed it but not much. the IAC (i think thats the top right one on the tb did nothing. well then comes the TPS. I unplugged it and it hiccuped a little. then i tap the gas and it goes from 2300 to 950 in about 6 seconds. then idles smooth. i tap the gas it shoots right up to 1500 and goes right back to idle. i do that a few times and same result. i plug the tis back in and it idles. but when i tap the gas rpms shoot to 2000 and stay there. tap the gas again goes to 2500 and slowly goes back to 2000. i unplugging it, tap the gas, then rpms go to 950 and we are golden. get back in car and get codes finally. awesome. so i pull them and get

P0122 TPS circuit low input
P0507 Idle air control system RPM high
p0121 TPS circuit range.

now theres no way the low input and range codes came within the 30 seconds the tis was unplugged. so i assume those codes were just about to come on but now that i hopefully found the culprit i have to get a TPS before my tune which is tomorrow so thankfully we may have gotten this. it sucks i sold my old tb with good sensors on it 3 months ago. off to the dealer tomorrow i guess

 

Don't know if you already did this but when you adjust the throttle body screw you have to reset the TPS.
unplug it.
Turn key on for like 30 seconds.
Turn key off and let it sit for a few seconds
Plug TPS back in.
Then start car.
maybe that helps.

I get how frustrating it can be, my tuner just finally figured out my idle probably today and I am so relieved.

 

Good to know. I'l let the tuner do it tomorrow

 

Try the TPS reset as mentioned.

After that you (or your tuner) will want to throw a meter on the TPS and see what voltage you are getting at idle. It should be around 0.5V. Mine was up at .744 and it caused all sorts of idle issues since the ecm is seeing that as a few % open throttle position. I believe it needs to be under 0.6V at idle for the ecm to think the car is at "idle" aka 0% throttle.

 

IIRC, some controllers would rezero up to 0.74V, many will not rezero above 0.69V

 

i just bought an auto zone sensor because the dealer is non returnable so will try to reset. then try the new sensor and a reset.

 

i have a basic scanner. tried the reset method twice. the scanner is saying .7% with car off. i slowly depress pedal and the numbers continue to climb. when i get about 1/4" away from the floor i get 99% then when i got past that i get 0%. so fun throttle is 0%. this is a nick williams.....thoughts?

 

found it. so the throttle cable is too short. i did the reset a few times did nothing. i noticed even with the idle screw to nothing and the tb blade could still be pushed closed a little more. i disconnected the cable did the reset and now im reading 0. i hook the cable back up and now im at 5%. so now what....my tune is today and i need a longer cable

 

yayyyyyy!!!!!!!!!i never knew u could adjust the length off ur cable. i reset it after i removed the cable, got it to say 0. then attached cable where it read 5%. adjusted the length until it said 0. tightened the clasp. opened and closed it a few times and it always said 0 at rest. and the car idles perfectly fine. thank u ls1tech for giving me the reset procedure. i feel like u should always do this when installing a new tb but i never read it