Lsx.silverado

I have a 08 aluminum 5.3 with ls3 cam eldelbrock performer rpm intake and the gm MSD controller in my 82 Chevy short box. The carb I'm running is a Quickfuel slayer 600 vac secondary's. I'm running number 1 timing chip in the box haven't done a custom tune yet. For pump its a holley red and I got 6 psi of line pressure with the floats set half way up the glass. I got the air fuels half a turn out with 19pounds of press at idle.

Problem is I step on the gas and it hesitates and if I stay in it it will die. I usually feather the gas then ease into the throttle and she takes off. It doesn't back fire just pops a bit when it hesitates. I thought it was the pump shot so I swapped out the 31 squirter for a 35. I helped on acceleration but still stumbles off idle. I got a pack of pump cams but have yet to change them. If anyone has an idea what's causing the problem I'd like to know thanks.

Lsx.silverado

I also had an issue with the cam sensor plug when I was wiring the controller. I spliced in a new correct pig tail because the one it came with wouldn't plug in. Hope I got the wires right.

Pop N Wood

iTrader: (1)

The LS2 cam sensors have a smaller plug and are wired differently than the LS1 sensors. If you swapped in a new plug, then make sure you swapped the outer two wires. Won't effect the way the car runs but will make a difference when starting it. BTW, you could have pushed the pins out of that one plug and repined them into the other. No reason to cut anything.

I take it you set the idle screws until you got max vacuum.

If it doesn't stumble with slow throttle movements but does with quick ones, then that is the time to adjust the accel pump circuit. Sounds like you need more shot quicker. Holley lists charts showing the capacity and how quickly each color cam comes on. You might just try a bigger cam as well as nozzle.

Also make 100% sure the accel linkage is adjusted so even the slightest throttle movement causes a nice strong squirt down the throat.

Look through the stickies on this forum for carb set ups and timing curves. Your timing will affect the stumble too. That #1 chip is almost certainly not optimal.

Last bit of advice, invest in a wide band. You can mask that stumble with enough accel pump shot but to really get the transition circuits right you need to adjust idle feed restrictors and air bleeds. I don't know how to do that with out a wide band.

ZONES89RS

iTrader: (25)

My quick way to fix is a 50cc accelerator pump kit.

stevecritt

iTrader: (3)

What size squirters are you ruining?

stevecritt

iTrader: (3)

just read your runing 35. I would think that would be plenty for what your running. I'm runing 37s.

stevecritt

iTrader: (3)

I would also make sure you have your idle screws set just right for max vac at idle, that will affect things too. Like zone said maybe bigger accel pump.