HAC Valve

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Sep 16, 2002
Threads
136
Messages
1,778
Location
Tucson, AZ
I thought I understood that the high altitude compensation (HAC) valve advances the timing as the elevation increases.

Does anyone know if this timing advance is all at once or gradually?

I drive from 2500’ till about 8000’, there is one spot at about 6000’ where it seems like the 40 begins to have more power.

The engine in my truck is from an ‘86 FJ60.

It has a lot of the stock stuff that came on that motor, including the electronic distributor, charcoal, canister, igniter, and HAC.

Thanks -

Rocky
 
Back
Top Bottom