Charcoal canister purge

[stevem]

If I remember correctly from my mechanic years and schooling back in the early 90's the charcoal canister was purged to the engine by a temperature operated vacuum switch. I know today it is done by computer operated valve. I thought it was supposed to purge when the engine was warm and it was hooked to ported vacuum because the vapors would richen the mixture and you wanted a higher engine speed. Anybody try a set up like this?

Merry Christmas!!!

[CraigS]

Most cars also had some engine rpm or car speed or engine load input. The idea was that, as you mentioned, you can't just suddenly dump that purge flow in at idle for instance. So the older setup needed to have the engine accelerating moderately to absorb the purge. Newer systems also had more sophisticated valves so they weren't just closed or full open. They could either be partially opened or they could be pulsed at different rates to vary flow. I think you could get a similar effect w/ a momentary switch to open the valve and do it manually using the above guidelines.

[stevem]

Found some info online on Toyota's system for carbs. Just a temp switch that opened above 125 I think and then hooked to ported vacuum.

[CraigS]

That might work. Closing below 125 and then using ported vac to handle the parameters that I am used to w/ modern efi systems could do the trick. if you end up w/ some stumbles you could put a restrictor in the hose.

[stevem]

Any idea where to find a temp operated valve like that? I assume the canister themselves are somewhat universal.

[CraigS]

Can you figure which year and model Toyota you found that info for?