|
Register or Log In To remove these advertisements. |
|
|
|
|||||||
 |
|
|
Thread Tools | Display Modes |
|
|
09-29-2018, 04:40 PM
|
#1 |
|
Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
|
Motor goes from lean to rich at idle.
Have a carbed 5.3 with LS1 cam, Brawler carb, edelbrock manifold. Put a wideband AFR on it this weekend and noticed my fuel ratio goes from 14.5 to 11-12 after the motor runs for a bit. Any input?
Thanks Jay |
|
|
|
09-29-2018, 05:06 PM
|
#2 |
|
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
|
Re: Motor goes from lean to rich at idle.
Cold intake plenum!
What does it do once the intake is hot? |
|
|
|
09-29-2018, 06:27 PM
|
#3 | |
|
Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
|
Re: Motor goes from lean to rich at idle.
Quote:
If I lean it out am I at risk of being too lean before the motor warms up? Electric Choke doesn't stay on long enough. Have it set at just closed when outside temp is 70 degrees. Last edited by Bobbed72; 09-29-2018 at 06:33 PM. |
|
|
|
|
|
09-29-2018, 05:33 PM
|
#4 |
|
Senior Member
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,796
|
Re: Motor goes from lean to rich at idle.
Adjust it at operating temperature (engine warm). The choke makes up the difference when it's cold.
__________________
I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
|
|
|
|
09-29-2018, 06:35 PM
|
#5 |
|
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
|
Re: Motor goes from lean to rich at idle.
Intake is cold when it goes rich!
The fuel vapour goes from fine mist to heavier fuel droplets (liquidizes).Heavier fuel doesn’t burn well and goes out the exhaust. Shows rich on your analyzer. When your intake is hot the fuel vapour stays normal. Try this test. When it goes rich shut off the motor for 5 minutes. The intake should warm up from heat soak in the motor. Hot air rises and heats the intake plenum. Should stay lean then. |
|
|
|
|
09-29-2018, 08:09 PM
|
#6 | |
|
Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
|
Re: Motor goes from lean to rich at idle.
Quote:
|
|
|
|
|
|
09-29-2018, 08:17 PM
|
#7 | |
|
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,512
|
Re: Motor goes from lean to rich at idle.
Quote:
|
|
|
|
|
|
10-01-2018, 04:26 PM
|
#8 |
|
Registered User
Join Date: Oct 2005
Location: Northern Arkansas
Posts: 1,127
|
Re: Motor goes from lean to rich at idle.
Did you set up the idle mixture using a tach or vacuum guage?
|
|
|
|
|
10-01-2018, 04:44 PM
|
#9 |
|
Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
|
Re: Motor goes from lean to rich at idle.
Vacuum gauge. Pulling around 20".
|
|
|
|
|
09-29-2018, 08:12 PM
|
#10 |
|
Registered User
Join Date: Apr 2017
Location: Hillsboro, OR
Posts: 80
|
Re: Motor goes from lean to rich at idle.
Have to revise my problem statement. Took it for a drive after posting and it was 13.5 at start. Motor cold and within a minute was 11 to 12.
|
|
|
|
|
| Bookmarks |
|
|
Hybrid Mode
