What should my idle speed be?
08-12-2010, 06:37 PM
#1
Member
Thread Starter
Join Date: Nov 2009
Location: Springfield, Oh
Posts: 153
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 Camaro RS
Engine: Was L03 305 TBI...now BB 454 :)
Transmission: 700r4
Axle/Gears: 2.73
What should my idle speed be?
Ok, I've done some research but haven't found much of anything. I want to know what my idle speed should be at start up, and after it warms up to operating temperature. I have an L03 305 and that idles around 1000rpm. Sometimes more recently it's been 1500rpm. It worries me that it's idling higher than when I first bought it.
08-12-2010, 06:40 PM
#2
Supreme Member
Re: What should my idle speed be?
When it's fully warmed up it should be around 600 RPMs. Less in gear.
When it's cold it depends on how cold but 1100-1200 on first startup is pretty normal.
Before you go looking for engine problems, verify that your tach is reading correctly (look at the RPMs from an scan tool, if you have access to one) to verify that the reading on the tach is close to the reading the computer is seeing. Stock 3rd gen tachs are notorious for going out of whack.
After that, vacuum leaks, bad throttle position sensor and a seized up IAC valve are the next usual suspects on the list.
When it's cold it depends on how cold but 1100-1200 on first startup is pretty normal.
Before you go looking for engine problems, verify that your tach is reading correctly (look at the RPMs from an scan tool, if you have access to one) to verify that the reading on the tach is close to the reading the computer is seeing. Stock 3rd gen tachs are notorious for going out of whack.
After that, vacuum leaks, bad throttle position sensor and a seized up IAC valve are the next usual suspects on the list.
08-12-2010, 06:47 PM
#3
Member
Thread Starter
Join Date: Nov 2009
Location: Springfield, Oh
Posts: 153
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 Camaro RS
Engine: Was L03 305 TBI...now BB 454 :)
Transmission: 700r4
Axle/Gears: 2.73
Re: What should my idle speed be?
Yea, it's idling like that now and it's 92 outside lol! That can't be good can it?!? I don't have access to such a tool to read the RPM's, don't know where I would either. It drops down to 700-800rpm when in gear. I'm new, so I have to ask. What's the IAC valve, and where is it? Same with the throttle position sensor. I appreciate the quick response to this thread!
08-13-2010, 07:18 AM
#4
Supreme Member
Re: What should my idle speed be?
Both are in the throttle body assembly. Idle Air Control solenoid (IAC) is a square 4 wire connector on the pass side/rear corner of the throttle body. Unplug the connector and then unscrew the IAC solenoid from the TB with a big wrench (1" or bigger, if memory serves). TPS is a 3 wire plug and it has a couple screws holding it onto the TB.
08-13-2010, 09:53 AM
#5
Member
Thread Starter
Join Date: Nov 2009
Location: Springfield, Oh
Posts: 153
Likes: 0
Received 0 Likes
on
0 Posts
Car: 1992 Camaro RS
Engine: Was L03 305 TBI...now BB 454 :)
Transmission: 700r4
Axle/Gears: 2.73
Re: What should my idle speed be?
Thanks again for the info! I'll have to check those out! Is there a way to see if they're working properly without having to buy new ones?
08-13-2010, 10:06 AM
#6
Supreme Member
iTrader: (128)
Join Date: Aug 2009
Location: Central California
Posts: 1,821
Likes: 0
Received 37 Likes
on
34 Posts
Car: 92 Camaro RS
Engine: LO3
Transmission: T5
Axle/Gears: stock
Re: What should my idle speed be?
Here's an article from the technical articles section that may help https://www.thirdgen.org/tpimod2 Also check out the TBI board, at the top there is a "new to TBI, check this out" thread that has lots of handy info. They're actually pretty easy to work with, you just have to find out how all the parts work together. Have fun! And do a search on the TBI forum for IAC cleaning. There's some good info there as well
Thread
Thread Starter
Forum
Replies
Last Post
someone972
Transmissions and Drivetrain
6
08-30-2015 12:52 AM
