Hesitation When Accelerating

[jhv48]

Being a vacuum secondary AVS Holley, most likely you’re experiencing a momentary lean condition because the secondaries aren’t opening fast enough.
Easily cured. My guess is when rebuilt, the secondary spring was replaced with a stronger spring than your car needed. Jump over to this site and it will show you how to replace the spring to a lighter one.
https://documents.holley.com/199r9934-3rev4.pdf

[patrickt]

It's easier than you think to not get the spring put in right or to make a hole in the vacuum thing or screw it up another way. It's one of the more irritating simple tasks on older engines.

[eschaider]

Originally Posted by jhv48

Being a vacuum secondary AVS Holley, most likely you’re experiencing a momentary lean condition because the secondaries aren’t opening fast enough.
Easily cured. My guess is when rebuilt, the secondary spring was replaced with a stronger spring than your car needed. Jump over to this site and it will show you how to replace the spring to a lighter one.
https://documents.holley.com/199r9934-3rev4.pdf

Secindries that open too quickly do not enriched the mixture, they lean the mixture because they introduce more air w/o the appropriate increase in fuel volume.

The spring in the secondary vacuum diaphragm retards the opening of the secondaries. Increasing spring strength slows the opening event. Decreasing spring strength speeds up the opening event.

If the secondaries are already opening too fast, installing a lighter spring will only aggravate the problem.


Ed