different idle problem

**Brad(WS/Z0.6)** · 01-29-2009, 10:12 AM

ok..i know alot of you on here have posted up describing your idle to be stuck at about 1600-1800 RPM's....but most of you have had TB replaced or done something involving the TB...but mine does this exact thing and i haven't touched my throttle body...EVER!! it just started doing this one day...i have done some major engine upgrades, but the problem appeared before any of that...when i roll (not pushing the throttle at all)..my RPM's jump to 1800 and stay..then when i come to a complete stop...it will drop back to normal (900-1000)....anyone know why this happens??? It annoys the living PISS out of me!!!!

**greenTA** · 01-29-2009, 10:48 AM

What all is done to your car? If you have a big cam you might want to get it retuned. When mine starts to lose its tune over time it will do that.

**Brad(WS/Z0.6)** · 01-29-2009, 11:16 AM

Originally Posted by greenTA

What all is done to your car? If you have a big cam you might want to get it retuned. When mine starts to lose its tune over time it will do that.

well, that may be the problem..although it started to do this before i swapped the cam...but i completely tore everything off of my engine down to the block...then i bought all the parts off a Z06 block and put them in mine...note that the Z06 motor was brand new..0 miles...thought i had it tuned good after the work..but maybe it needs another...where do you suggest taking it???

**greenTA** · 01-29-2009, 06:13 PM

haha well Im in Colorado so I take it to DynoPro but I have no idea about where you're at. Try to find a local LSX forum and ask them?? Or maybe look for someone on here that is near you.
Also, it used to do that when my clutch wasn't warmed up. I would be coming to a stop and would put in the clutch in 2nd gear and the RPM's would go to like 1800, then i would put it in nuetral, let it out, then put it back in first and it would go back down. But i still have the stock clutch waiting to be replaced so I'm not sure if that could be it?????

**Kaotic_ws6** · 01-29-2009, 06:31 PM

Originally Posted by Brad(WS/Z0.6)

ok..i know alot of you on here have posted up describing your idle to be stuck at about 1600-1800 RPM's....but most of you have had TB replaced or done something involving the TB...but mine does this exact thing and i haven't touched my throttle body...EVER!! it just started doing this one day...i have done some major engine upgrades, but the problem appeared before any of that...when i roll (not pushing the throttle at all)..my RPM's jump to 1800 and stay..then when i come to a complete stop...it will drop back to normal (900-1000)....anyone know why this happens??? It annoys the living PISS out of me!!!!

mine does this too. (but not all the time) it sucks because when it does it people prolly think we dont know how to drive or are trying to rev at them, because my cars extremely loud. im with you its annoying as hell

**Brad(WS/Z0.6)** · 01-29-2009, 07:04 PM

Originally Posted by Kaotic_ws6

mine does this too. (but not all the time) it sucks because when it does it people prolly think we dont know how to drive or are trying to rev at them, because my cars extremely loud. im with you its annoying as hell

amen to that..i get those looks every day and it drives me insane!!!! i gotta fix it..

**Kaotic_ws6** · 01-29-2009, 07:18 PM

Originally Posted by Brad(WS/Z0.6)

amen to that..i get those looks every day and it drives me insane!!!! i gotta fix it..

yea but im not sure how tooo???

**Kaotic_ws6** · 01-29-2009, 08:59 PM

Originally Posted by Brad(WS/Z0.6)

amen to that..i get those looks every day and it drives me insane!!!! i gotta fix it..

hey what kinda power do you make?

**0rion** · 01-29-2009, 11:28 PM

it could be a tuning issue but since you said it did it before the cam you may want to start looking at unmetered air entering the engine. First thing to check is the pcv hose that goes into the intake. That will crack along the back side and let air get in. Go along all of your vacuum hoses and look for leaks. Also, check between the maf sensor and the throttle body and make sure nothings leaking in after the maf. I'm betting it's a vacuum hose and probably that pcv hose. Check up and down it real good.

**edbird** · 01-30-2009, 04:17 AM

Too fast an idle speed. The powertrain control module (PCM) will maintain normal idle speed and compensate for a small vacuum leak by closing down the throttle body air bypass. But if the leak is too large and the idle control system cannot compensate for the extra air, the engine may idle too fast. Common leak paths include the throttle body gaskets, intake manifold gasket, any of the engine vacuum fittings, hoses or vacuum-operated accessories (such as the power brake booster or EVAP canister purge valve). It is even possible that leaky O-rings around the fuel injectors may be allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft.

The above is from a very infomitive site:http://www.aa1car.com/random-misfire/
Check it out- tells you how to troubleshoot this problem with a vacuum gauge.

**Brad(WS/Z0.6)** · 01-30-2009, 06:18 AM

Originally Posted by Kaotic_ws6

hey what kinda power do you make?

475rwhp....420rwtq...cost me $12,000 to get there...

**Brad(WS/Z0.6)** · 01-30-2009, 06:20 AM

Originally Posted by edbird

Too fast an idle speed. The powertrain control module (PCM) will maintain normal idle speed and compensate for a small vacuum leak by closing down the throttle body air bypass. But if the leak is too large and the idle control system cannot compensate for the extra air, the engine may idle too fast. Common leak paths include the throttle body gaskets, intake manifold gasket, any of the engine vacuum fittings, hoses or vacuum-operated accessories (such as the power brake booster or EVAP canister purge valve). It is even possible that leaky O-rings around the fuel injectors may be allowing air to leak past the seals. Another overlooked item can be a worn throttle shaft.

The above is from a very infomitive site:http://www.aa1car.com/random-misfire/
Check it out- tells you how to troubleshoot this problem with a vacuum gauge.

Originally Posted by 0rion

it could be a tuning issue but since you said it did it before the cam you may want to start looking at unmetered air entering the engine. First thing to check is the pcv hose that goes into the intake. That will crack along the back side and let air get in. Go along all of your vacuum hoses and look for leaks. Also, check between the maf sensor and the throttle body and make sure nothings leaking in after the maf. I'm betting it's a vacuum hose and probably that pcv hose. Check up and down it real good.

Hey thanks guys!! i'll try to get a look this weekend..sounds like a very reasonable problem and it's one that i haven't had time to check into yet. I'll let you guys know what i find out...thanks again

**Kaotic_ws6** · 01-30-2009, 06:51 AM

Originally Posted by Brad(WS/Z0.6)

475rwhp....420rwtq...cost me $12,000 to get there...

DAMN! great numbers.

**Brad(WS/Z0.6)** · 01-30-2009, 07:10 AM

Originally Posted by Kaotic_ws6

DAMN! great numbers.

Thanks man!! you've got some pretty impressive digits yourself!!!

**Kaotic_ws6** · 01-30-2009, 08:03 AM

Originally Posted by Brad(WS/Z0.6)

Thanks man!! you've got some pretty impressive digits yourself!!!

thanks, i think im doin alright for the time bein.. i hope to get alittle better numbers with a fast 92/92 AND an ugraded fuel system as i t is stock now, and a GOOD tune. ill build the bottom end eventually but dont have that kinda money right now. just as your guess how much more do you think my car will make with that?

**Brad(WS/Z0.6)** · 01-30-2009, 09:22 AM

Originally Posted by Kaotic_ws6

thanks, i think im doin alright for the time bein.. i hope to get alittle better numbers with a fast 92/92 AND an ugraded fuel system as i t is stock now, and a GOOD tune. ill build the bottom end eventually but dont have that kinda money right now. just as your guess how much more do you think my car will make with that?

ummm...you may be able to jump up to 450....thats if you get it tuned to perfection...mine needs a little tune as of right now but it's not that big of a deal...torque shouldn't go up alot tho..you'll have to build up your bottom end and thats when you'll start seein bigger numbers in that ballpark...but new maf + new fuel sys. + GOOD tune = around 450....probly a 25 to 30 jump..when do you plan on getting it done??

**Kaotic_ws6** · 01-31-2009, 07:19 AM

Originally Posted by Brad(WS/Z0.6)

ummm...you may be able to jump up to 450....thats if you get it tuned to perfection...mine needs a little tune as of right now but it's not that big of a deal...torque shouldn't go up alot tho..you'll have to build up your bottom end and thats when you'll start seein bigger numbers in that ballpark...but new maf + new fuel sys. + GOOD tune = around 450....probly a 25 to 30 jump..when do you plan on getting it done??

not right now im broke