High Idle?
Thread Starter
6th Gear
Joined: Feb 2012
Posts: 6
Likes: 0
High Idle?
Hey all my 79 L82 has an abnormal idle. At least I think it is my first car like this. It idles between 1500-2500 rpm but it stats there for quite a long time. Even when its warm and I take it out and its completely warm it still idles high usually if I put it in park and tap the gas it will idle down to normal. Any ideas? Thank you.
Melting Slicks
Joined: Aug 2010
Posts: 2,487
Likes: 10
From: Palm Beach Florida
St. Jude Donor '12
First thing to check is ALL Vacuum hoses. Make sure they are ALL connected, and none have cracks or holes. Make sure the timing is correct, then from there adjust the idle screw. I have a 77, but I believe your idle should be 550 - 750 RPM.
Safety Car
Joined: Jun 2004
Posts: 4,371
Likes: 223
From: Beecher Illinois
Is the choke releasing? There's a thermostatic spring in that round area on the pass side of the carb. Broken spring? but not likely. There's a stepped cam connected to the choke that the fast idle screw rides on. That may be why it idles down sometimes when you blip the throttle, the stepped cam rotates to the next step.
And there's a FAST idle adjusting screw, pass side front of carb, kinda hard to see.
Also, make sure the Air Conditioning switch isn't "on". There's a fast idle solenoid on the carburator that kicks the idle up, but not as high as yours. Pull the elec connector off of it. Driver side front of carb.
And there's a FAST idle adjusting screw, pass side front of carb, kinda hard to see.
Also, make sure the Air Conditioning switch isn't "on". There's a fast idle solenoid on the carburator that kicks the idle up, but not as high as yours. Pull the elec connector off of it. Driver side front of carb.
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
You may not have a problem. On a cold start (engine temp, not outside air temp), the fast idle is supposed to kick in and assist with getting the engine up to temperature quickly.
The fast idle is supposed to kick off with a tap of the accelerator pedal.
Based on what you have posted, your fast idle and fast idle kick off appear to be working like they should.
The fast idle is supposed to kick off with a tap of the accelerator pedal.
Based on what you have posted, your fast idle and fast idle kick off appear to be working like they should.
Advanced
Joined: Jan 2011
Posts: 91
Likes: 1
From: Flemington NJ
I'm in the process of having my carb rebuilt (1980) - I had an inconsistent idle as well. The rebuilder showed me how the worn throttle shaft bushings can affect idle quality. Just another item to check if you end up removing the carb.
Melting Slicks
Joined: Sep 2004
Posts: 3,225
Likes: 667
From: Northeast
You dont say whether it is a 4spd or auto, original or ?, but a 79 L82 should have a cold idle of 1300 rpm when you first set the choke. On a 4spd it's 1600rpm. It should not be 2500.
After about 30 seconds you should be able to blip the pedal and the revs come down a few hundreds. Blip again later and it should bring the idle down to 700 in drive or 900 in neutral for a 4spd. This info should be on the sticker on the firewall (driver's side).
After about 30 seconds you should be able to blip the pedal and the revs come down a few hundreds. Blip again later and it should bring the idle down to 700 in drive or 900 in neutral for a 4spd. This info should be on the sticker on the firewall (driver's side).
