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Old 10-15-2012, 05:02 PM
75gmck25 75gmck25 is offline
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There are multiple problems that can cause an Edelbrock 1406 to bog. Often it can be fixed by simply changing the step-up springs so that it transitions to the power mode more quickly as the vacuum drops.

The stock Edelbrock step-up spring on the 1406 will transition from cruise to power at 5" of vacuum. This may create a bog because it goes too lean when the throttle opens and the rods pop up too late. Simply switching to 6", 7" or 8" springs will make it transition to the power step on the rod sooner, which often cures the initial bog. That transition bog usually cannot be resolved by adjusting the accelerator pump, which is the first change many folks try.

I added a wideband AFR meter to my truck and it was very easy to see when the Edelbrock went lean during acceleration, and also very easy to see how it improved by changing the step-up springs. In my case a switch to 6" springs resolved the problem

I also experimented with changing the jets and rods, but this was a much more gradual change in AFR. You could see the change on the AFR meter, but it was tough to feel by seat-of-the-pants.

Bruce
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