help with high idle!
Thread Starter
TECH Enthusiast
iTrader: (20)
Joined: Nov 2005
Posts: 538
Likes: 1
From: Frisco, Texas
help with high idle! well i bought this car about a month ago now and it was running perfect when i got it...other than some cam surge every once in a while...well starting around 2 weeks ago the idle started moving on up daily to be higher and then leveled out at 1900 rpm exactly...then around 3-10 seconds later it will SLOWLY start going back down to the 950 desired idle....ive used carb cleaner to TRY to find a vacuum leak and no luck...since i was an lt1 guy before this i know absolutely nothing about the vacuum system on these cars...i know that the two 90 degree connectors for vaccum lines on the passenger side valve cover are both capped and the line that goes from the intake manifold to the throttle body is still there but a bolt is shoved in it to cap them off...also the throttle body does have the enlarged hole of 3/16's...im tired of this..it sounds ridiculous at stop lights and such having such a high idle! constantly sounds like i dont knwo how to drive a stick and revving it too high haha...please help me with this im so stumped
could make sure the intake manifold bolts are tightened down, the throttle body is snug against the manifold, the connections in the back of the manifold are plugged in tightly, the throttle body idle position screw might need a little adjustment, it could be any of a number of things. The only thing you know for sure is that unmetered air is getting into ur engine somwhere, so that means after the MAF. Some pics would probably be helpful, of ur setup in general and the psecific places you have capped off.
So your valvecovers are completely capped off and there's a line from the manifold to the TB? This is about as bass ackwards as I've ever seen.
Where are the crankcase gasses escaping? Is there a breather somewhere?
Our cars have tables in the PCM that allow the RPMs to hang at a certain RPM until a certain speed, but since it just started, I doubt it's tuning. Sounds like that "bolt" he put from the TB to the manifold is leaking by now and air is getting past the throttle body. This is causing the car to idle high and the IAC (idle air control) motor to close off to compensate. This takes a few seconds, which would explain the brief idle hang and the RPM's slowing down.
You could take the IAC motor out and clean it. It's the top driver side sensor on the TB. You could also cap off the line on the manifold and the line on the TB properly. Advance Auto sells 3/8" vacuum caps a dime-a-dozen.
Where are the crankcase gasses escaping? Is there a breather somewhere?
Our cars have tables in the PCM that allow the RPMs to hang at a certain RPM until a certain speed, but since it just started, I doubt it's tuning. Sounds like that "bolt" he put from the TB to the manifold is leaking by now and air is getting past the throttle body. This is causing the car to idle high and the IAC (idle air control) motor to close off to compensate. This takes a few seconds, which would explain the brief idle hang and the RPM's slowing down.
You could take the IAC motor out and clean it. It's the top driver side sensor on the TB. You could also cap off the line on the manifold and the line on the TB properly. Advance Auto sells 3/8" vacuum caps a dime-a-dozen.
Thread Starter
TECH Enthusiast
iTrader: (20)
Joined: Nov 2005
Posts: 538
Likes: 1
From: Frisco, Texas
yes the line from the tb to the intake manifold is like a complete uturn and has something shoved in it to shut it off....and yes i have a breather on the oil cap position ill take better pics after work today
Thread Starter
TECH Enthusiast
iTrader: (20)
Joined: Nov 2005
Posts: 538
Likes: 1
From: Frisco, Texas
Trending Topics
Thread Starter
TECH Enthusiast
iTrader: (20)
Joined: Nov 2005
Posts: 538
Likes: 1
From: Frisco, Texas
ok well i had enough time before work real quick
that one is capped with something in it like a piece of rubber
that one is capped with a screw? lol
the screw in the one to the tb from intake mani and you can also see that the bend is too much for the line and so it kinks and folds over
the bulge from the bolt and my overly priced snap on box
that one is capped with something in it like a piece of rubber that one is capped with a screw? lol the screw in the one to the tb from intake mani and you can also see that the bend is too much for the line and so it kinks and folds over the bulge from the bolt and my overly priced snap on box 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
wow are you serious! Get some F'in vacuum caps, its like 3 bucks at autozone for a package of them. It will seal them properly, i can almost promise you this is your issue.
Ditch that hose too and just cap those ports off too.
Ditch that hose too and just cap those ports off too.
