funky popin noise when cold help

[broncoman6524]

ok im pretty sure this has something to do with the carb. When its cold, it idles fine. put iit in drive and idle its fine. accelerate lighty, its fine. get on it, it stumbles and makes a popping, push harder and it would go away. Its startin to piss me off. i fiddled with the two main screws on the front of the carb, with the vacum gauge hooked to it and got them to about 18ish lbs of vacuum each side. It helped but it didnt fix it. the choke is set at dead zero.

Its a 350 edelbrock 1406 carb,and performer intake.

THANKS WHOEVER TELLS ME WTF IS WRONG lol

 

[mtnman210]

could it just be that it's COLD. you said it only does it when it's cold. what about after you've been driving for a while.

Mine will do the same thing especially once outside temps drop(here in so cal around 40-50 in the am). I can drive it but if I get on it right away It'll pop and backfire and if I don't let off stall it. I need a good 15mins of warm up and then some easy drive time before I can even consider the motor warmed up.

 

[broncoman6524]

thats waht i figured. but the thing is that it didnt do it like 2 months ago. It wasnt realy a problem, but it got worse and worse.

 

[1985_K5_Silverado]

Perhaps your step-up springs are a little too weak, and aren't letting the metering rods lift soon enough. Are the step-up springs the stock (yellow 4"Hg) 1406 springs? If so, you might try the orange (5"Hg), pink (6"Hg), or plain (7"Hg) springs to get those rods up a little quicker. The spring assortment (5 pairs, EB #1464) is only about 5 or 6 bucks.

 

[broncoman6524]

um im not 100% sure what your tallkin about...lol when you look down from the top of hte carb, are you tlakin about the springs under the little triangle lookin thingys on either side of the barrels?

 

[1985_K5_Silverado]

Yeah, these springs. The carb manual (get it from their web site on PDF if you don't have it) explains the tuning process. Don't torque on the cover screws too hard!

 

[1985_K5_Silverado]

To quote the manual:

CALIBRATING THE POWER MODE STAGING


The Step-Up function, which moves the Metering Rod to the Power Mode, is controlled by the Step-Up Spring. The base calibration has a spring which "stages" rich at 5" Hg. If your vehicle has a mid-throttle driveability problem that is encountered as the throttle is gradually opened, but then goes away upon further opening, it may be possible to eliminate the lean spot by using a stronger Step-Up Spring. The available Step-Up Springs are listed in the following chart along with their respective "staging" point.

It is best to select a new spring on the basis of vacuum readings, but in the absence of a gauge, try the strongest spring (highest vacuum rating) to see if the problem goes away. If the drive problem is cured by the strong spring, try the next weakest spring as well. If the strong one does not help, then the calibration problem is related to the A/F metering stage of either the Cruise or Power Modes. Use the Calibration Reference Chart to help select another combination.

 

[broncoman6524]

alright thanks bud. ill get the springs from discount and then see what happens lol