The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Help with high alt. calibration on Edelbrock 1405

silverstreak · 02-16-2010, 09:21 PM

The step up spring controls the point at which the power circuit comes into play, or when the metering rod starts to rise up out of the primary jet. If you notice a bad hesitation just as you accelerate (but your accelerator pump is OK) then you need to switch to a stiffer spring. Try the one you have now, the go from there.
The best advise I can give is get a wideband Oxygen sensor to use as tuning aid. Ever since I got mine, I won't tune a carb without it.

02-16-2010, 09:21 PM	#2
silverstreak Registered User Join Date: Mar 2009 Location: USA Posts: 255	Re: Help with high alt. calibration on Edelbrock 1405 The step up spring controls the point at which the power circuit comes into play, or when the metering rod starts to rise up out of the primary jet. If you notice a bad hesitation just as you accelerate (but your accelerator pump is OK) then you need to switch to a stiffer spring. Try the one you have now, the go from there. The best advise I can give is get a wideband Oxygen sensor to use as tuning aid. Ever since I got mine, I won't tune a carb without it.