cold idle speed
Thread Starter
|
Tuned
Joined: Mar 2015
Posts: 272
Likes: 0
From: Texas
cold idle speed
OK so I'm having trouble with the idle speed on my 79 f150 with a 460. when i first start the engine when its cold and let off of the gas pedal it dies out but if i keep my foot on the pedal just a little bit it'll stay running then when it warms up i can let off of the pedal and it will idle just fine. what could my problem be??????? i read somewhere that it could be a bad accelerator pump. if it helps any I'm running a holley 4180 4bbl carb. oh and i do have teeny tiny gas leak looks like from around the front my carb between the throttle body and the intake manifold
Posting Guru
Joined: Aug 2010
Posts: 1,761
Likes: 8
From: Knoxville, TN
Accelerator pump only has to do with throttle transients, not idle.
Cold idle is a function of the choke adjustment and the cold idle adjustment - that's where you should start. The instructions for Holley's rebuild kit include adjustment instructions - you should be able to find them online.
Fuel leak is a problem though ... might be the o-ring on your idle mixture control adjustments or something like that if it's coming from the front bottom. Or that could be at the accelerator pump and running down. A rebuild kit would include all the relevant O-rings, gaskets, etc.
Cold idle is a function of the choke adjustment and the cold idle adjustment - that's where you should start. The instructions for Holley's rebuild kit include adjustment instructions - you should be able to find them online.
Fuel leak is a problem though ... might be the o-ring on your idle mixture control adjustments or something like that if it's coming from the front bottom. Or that could be at the accelerator pump and running down. A rebuild kit would include all the relevant O-rings, gaskets, etc.
Thread Starter
|
Tuned
Joined: Mar 2015
Posts: 272
Likes: 0
From: Texas
Fuel leak is a problem though ... might be the o-ring on your idle mixture control adjustments or something like that if it's coming from the front bottom. Or that could be at the accelerator pump and running down. A rebuild kit would include all the relevant O-rings, gaskets, etc.
Posting Guru
Joined: Aug 2010
Posts: 1,761
Likes: 8
From: Knoxville, TN
Idle mixture adjustments were covered with hardened plugs on these, and need to be drilled out to rebuild/adjust that, but if the anti-tamper plugs are in place, your problem is likely elsewhere - those are press-fit and I don't think fuel would leak around them even if your O-rings were starting to go.
The choke adjustment and cold idle speed adjustment aren't a function of idle mixture, so you don't need to worry about the anti-tamper plugs there either - those adjustments are entirely accessible.
The choke adjustment and cold idle speed adjustment aren't a function of idle mixture, so you don't need to worry about the anti-tamper plugs there either - those adjustments are entirely accessible.
Posting Guru
Joined: Aug 2010
Posts: 1,761
Likes: 8
From: Knoxville, TN
Thread Starter
|
Tuned
Joined: Mar 2015
Posts: 272
Likes: 0
From: Texas
Idle mixture adjustments were covered with hardened plugs on these, and need to be drilled out to rebuild/adjust that, but if the anti-tamper plugs are in place, your problem is likely elsewhere - those are press-fit and I don't think fuel would leak around them even if your O-rings were starting to go.
The choke adjustment and cold idle speed adjustment aren't a function of idle mixture, so you don't need to worry about the anti-tamper plugs there either - those adjustments are entirely accessible.
The choke adjustment and cold idle speed adjustment aren't a function of idle mixture, so you don't need to worry about the anti-tamper plugs there either - those adjustments are entirely accessible.
Posting Guru
Joined: Aug 2010
Posts: 1,761
Likes: 8
From: Knoxville, TN
They're hardened steel ... if you go through the plugs with an easy-out, as the instructions suggest, you're likely to fail. Most people drill a hole in the casting just behind the plug and push it out from the back. If you search online for how to drill out the plugs on a 4180, you'll find some pictures.
Thread
Thread Starter
Forum
Replies
Last Post
daveinva
1973 - 1979 F-100 & Larger F-Series Trucks
11
Nov 8, 2018 08:15 AM
cstephens
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
6
Feb 18, 2018 07:49 PM
El Padrino
1973 - 1979 F-100 & Larger F-Series Trucks
4
Feb 12, 2014 07:23 PM
marioc956
Fuel Injection, Carburetion & Fuel System
9
Apr 6, 2007 07:54 PM
