High idle ls1
Thread Starter
Teching In
Joined: May 2015
Posts: 31
Likes: 1
High idle ls1 i swapped a ls1 into my Nissan 240sx and the idle is high. The tps is at the right adjustment and to my knowledge I have no vacuum leaks. It has not been tuned yet and the motor has a lunatic 232/238 can in it. Would tuning it fix my idle problem? Or is this something that has to be addressed before. It idles fine however it won't drop below around 1200-1500 rpm
Thread Starter
Teching In
Joined: May 2015
Posts: 31
Likes: 1
these are the specs
- 288
- Duration @ .050 (Int/Exh): 232/238
- Gross Valve Lift (Int/Exh): .599"/.601"
- LSA/ICL: 113/109
- Valve Lash (Int/Exh): Hyd/Hyd
- RPM Range: 2400-7000
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
What intake and throttle body? Does idle hold steady at 1200? To find a vacuum leak let idle stabilize with the car in closed loop and run a scan tool under the hood and watch stfts while spraying starting fluid around the intake. If you find a leak the idle may not change much but fuel trims will shoot deep in the negatives. Sounds like a vacuum leak or the throttle blade is drilled or open to far and the tps is just reset for its new position. You have to be getting extra air from some where if the tps is at zero idling. The ecm is shooting for whatever idle is set at in the tune and it can't close the IAC enough to compensate.
Trending Topics
Thread Starter
Teching In
Joined: May 2015
Posts: 31
Likes: 1
What intake and throttle body? Does idle hold steady at 1200? To find a vacuum leak let idle stabilize with the car in closed loop and run a scan tool under the hood and watch stfts while spraying starting fluid around the intake. If you find a leak the idle may not change much but fuel trims will shoot deep in the negatives. Sounds like a vacuum leak or the throttle blade is drilled or open to far and the tps is just reset for its new position. You have to be getting extra air from some where if the tps is at zero idling. The ecm is shooting for whatever idle is set at in the tune and it can't close the IAC enough to compensate.
ok. The intake is a fast lsxr102 and the TB is a Holley 95mm
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
10 Second Club
Joined: Jan 2010
Posts: 2,317
Likes: 20
From: Hurley, VA
it is a cable throttle body right? I would bet If you looked at IAC counts they're pegged. I had a professional products (I believe) on my stock intake once. The throttle screw was way off. If you don't have any vacuum leaks try adjusting it closed and do a tps reset. That throttle body may be adjusted out to far out of the box.
