TXsilverado

iTrader: (18)

I drove the s10 about 250 miles over the weekend. it has an extremely lean spot at 2k rpm with the converter locked. like 17 AFR and the engine starts to miss. it clears up by 2300 rpm. what do I need to do to clean this spot up?

speedtigger

iTrader: (16)

If this lean condition happens under a bit of a load, go 1 number higher on the power valve and try it again.

89gmcs15

iTrader: (7)

I forced mine to have a lean condition while I was learning the carb tuning of individual parts. I think it went way lean at the transiting between idle and main circuits at right around 2k on my combo. It turned out that was a direct result from me changing the high speed air bleeds to too large. Not sayin that's your fix as I was WAY large on the size to get a direct reflection of what it changes. I'm just sayin that had a effect on that rpm range and a lean condition.

The power valve is a good thinking too if it's doin it only under a load and not cruising or slightly accelerating. Right?

Pop N Wood

iTrader: (1)

If it does it while cruising then go a size or two smaller on the idle air bleeds.

2K is right around the point where it transitions from the idle to the main circuits.

89gmcs15

iTrader: (7)

I could have been wrong on the bleeds I changed. But that's what I experienced when I went too large

TXsilverado

iTrader: (18)

unless you consider my converter locking a load. i have my converter locking at 50mph. once the converter locks at 50, the rpm drops right at 2k rpm. if i hold the throttle steady and just cruise that 2k rpm, the truck will start to hickup from being lean. if i slowly speed up it richens up by 2,300 rpm.

so the high speed bleed is the consensus. i may just get a full bleed kit to add to my carb tuning arsenal. at this point i only have a holley jet kit.

TXsilverado

iTrader: (18)

i also have an extreme rich condition at throttle tip in from a stop. would the high speed bleed also help this? i think the extreme rich condition comes from the transition slot opening. how do i slow down the fuel fed to that transition slot?

Pop N Wood

iTrader: (1)

You were talking about the high speed bleeds. I said to adjust the idle bleed. Larger bleeds should lean out the circuit at the top of it's range.

TXsilverado

iTrader: (18)

ok, so my plan at this point is to reduce the idle feed restrictor to try and get rid of this huge rich spot off idle when the transition slot comes in. then reduce the high speed bleed to try and get rid of this 2k rpm lean spot. sound about right?

Pop N Wood

iTrader: (1)

The air bleeds even out the mixture for a given circuit. Bigger bleeds, leaner mixture at the top of the band for that circuit. They can also affect when the carb transitions from one circuit to the other.

Reduce the IFR and you will lean out the mixture just off idle. You will also make the carb increasingly lean as it approaches the transition from the idle to the main circuit. If you then reduce the high speed bleed, you might move the main circuit down so it comes into play before 2K, but my guess is you will just start running rich at high RPM.

And my guess is you will just make your lean hole before 2K worse.