I have an 86 Toyota Pickup 22r. I'm trying to find out how to diagnose the distributor vacuum advance to find out if it needs to be replaced or not. I tested both tubes with vacuum. The one closest to the distributor will hold vacuum but slowly lose vacuum. The one further away from the distributor will not hold any vacuum at all. Does this mean that the vacuum advance diaphragm is bad?
Your vacuum advance unit is bad, both sides should hold vacuum. I had to replace the vacuum advance unit on a truck i owned a few years ago, and the only place i could find one at was the dealer, and it cost me 200.00 dollars (no joke), you can buy a complete new distributor for less than that.
Yea man, you wouldn`t think that part would be so expensive, maybe 50-60 dollars tops, but i had to have it. It wasn`t until later that i realized that i could have got a complete new distributor for alot less.