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post #1 of (permalink) Old 09-28-2000, 08:19 AM
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Evaporator Canister Question

1990 YJ 4.2 6 cylinder.
I read that if you squeeze the main purge line on the
evaporator canister & the idle changes you have a bad canister, How do I determine which line is the main purge line? I squeezed all of them except the one from the fuel tank. When I squeezed the one off the back of the carb. the idle went down. Is that the main purge line?

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post #2 of (permalink) Old 09-28-2000, 09:15 AM
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Re: Evaporator Canister Question

[img]/wwwthreads_images/icons/smile.gif[/img] Yes.[img]/wwwthreads_images/icons/crazy.gif[/img]

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post #3 of (permalink) Old 09-28-2000, 10:05 AM
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Re: Evaporator Canister Question

At ilde the purge valve opens up and sucks the vapor out of the purge canister. However, if the canister is bad (full of gas) the carb will suck out the raw gas, flood the engine and it'll die. The canister destruction can be caused by the cansiter just going bad or the tank being overfilled with gas and the overfill goes straight to the canister. It would be wise to check the canister for liquids...

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post #4 of (permalink) Old 03-05-2001, 12:23 PM
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Re: Evaporator Canister Question

My understanding is slightly different---I was under the impression that at idle , there is no ported vacuum signal to the CTO valve . Therefore, there is no purge signal reaching the Evap Cannister from the CTO. Hence , even at idle , with steady manifold vac reaching to the Evap Cannister along the main evap cann hose line, the evap Cannister will not allow the vac from manifold vac to pull vapors from evap cann to the intake manifold . Once the engine is revved and ported vac appears above the throttle plate, then the ported vac signal is passed from the carb port to the CTO , and then it is passed to the Evap Cann Purge Signal Port . This then permits the ongoing manifold vac to pull vapors through from the Evap Cann to the intake manifold . Does this sound correct ?

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