Wideband Tuning Holley Carb

[Vtec2V8]

I recently installed a AEM UEGO Wideband:
Engine:
350 SBC
280H Comp Cam
Holley Street Avenger
18 in HG at 900 Idle

Problem im having is when truck is at idle, the gauge is reading 17.4 to LEAN. seems no matter when i do i cant seem to richen the idle up at all. Mixture screws are rough 2 3/4 turn out. I havent been able to drive it yet, this is just warmed up and idling.

Is this normal for a carb to run lean at idle?

[Rickysnickers]

I have one of those carbs as well. I cannot get mine to run right either, but then again I hate carbs and don't really know how to tune them. During a search, I stumbled across this site. It might be helpful, https://www.hotrodders.com/forum/hol...ix-507033.html

[Dead Parrot]

For most applications, you want it lean at idle. If it is idling smooth(depending on cam,this can be a fairly loose definition for smooth), and making a good transition to moving throttle, then don't worry about it. In fact, lean it as much as you can and still have a smooth idle. No point in burning extra gas while not moving.

For a stock carb, the old method(before ratio meters were affordable) was something called lean drop. Adjust for max rpm/vacuum and then turn the mix screw(s) in(leaner) about a 1/4 turn(~50 rpm drop).

Remember, the IDLE mix screws are ONLY for idle. They have very little to do with anything once the throttle starts opening.

[andyh1956]

At 900 rpm you are prolly into main metering. Look at your boosters at idle & see if you have fuel dribble from them.
What power valve do you have installed on the primaries?
Does the Street Avenger use a power valve on the secondary?
Have you done the power valve blowout prevention mod to your carb yet?

[Captainfab]

I believe all of the Holley SA carbs come from the factory with PV blowout protection.

[mattfranklin]

There was a cool episode where the Roadkill Garage guys tuned a Holley by using a wide range exhaust sensor. It was season 3 episode 29 and they called it the "Tater Truck" because they bought it in Idaho.

Anyway, it was pretty cool how they systematically worked through tuning the jets, power valves, and so on. It is available on their closed paywall site. I've seen it pirate up loaded to youtube and dailymotion as well.

$5/mo to subscribe, but I enjoy it.

[GASoline71]

Originally Posted by Captainfab

I believe all of the Holley SA carbs come from the factory with PV blowout protection.

Yep... any Holley carb manufactured after 1994 has PV blowout protection already built in to it.

To the OP, if you're 2 3/4 turns out on your idle screws. It sounds like you have a vacuum leak.

Gary