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Old March 11th, 2018, 12:29
ljobbins ljobbins is offline
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renix charcoal canister vacuum

I tried searching for an answer but I couldn't find anything. I am looking for a reason why I have no vacuum to my charcoal canister.
A couple weeks ago I experienced a significant amount of pressure in my fuel tank and since then I checked to make sure the vents are not clogged, then the lines to the canister and it was all good. Then yesterday I checked to see if I even had vacuum at the airbox(source for the hose to canister) and I had zero vacuum. The engine was warm and I went from idle to full throttle with zero vacuum. So that would explain why I got over pressurization because the canister is not sucking the fumes out. But why would I not have vacuum from the airbox?
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Old March 12th, 2018, 17:39
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Ecomike Ecomike is offline
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Re: renix charcoal canister vacuum

Vacuum does not drive it. When the gas tank pressure builds to certain limit the check valve/vents on the gas tank open and vent gasoline vapors to the caron canister. Focus on that line and the carbon canister it self. When the engine is running it sucks outside air into canister, through the canister and out to intake manifold at least on Renix 87-90. OBD-II 96 up may have a solenoid to open the CC ventilation route? Check the firewall label drivers side for the Vac plumbing layout
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Old March 13th, 2018, 14:05
ljobbins ljobbins is offline
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Re: renix charcoal canister vacuum

How’s it suck air? And I don’t understand how the vapors would travel to or through the canister and to the intake if there is no vacuum. If there is no vacuum then pressure building up too fast wouldn’t be able to vent fast enough thus my problem a few weeks ago with overpressurization in the tank.
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Old March 13th, 2018, 14:06
ljobbins ljobbins is offline
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Re: renix charcoal canister vacuum

Explain further if you can please.
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Old March 13th, 2018, 14:36
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Ecomike Ecomike is offline
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Re: renix charcoal canister vacuum

When the engine is off, and the gas warms up during the day as temps rise, gas vapor pressure rises in the gas tank. Those vapors push their way to the carbon canister (into lets call it port #1) where they are adsorbed by the carbon.

When the engine is running the intake vacuum sucks fresh air into the canister (Port #2, it has no hose or nipple on the Renix rigs), and the gasoline de-sorbes from the carbon into the air drawn in from out side (port #2) and then flows out port #3 into the vacuum hose to the intake manifold where the gas vapors are used as fuel.

There should one hose going to the gas tank, one hose going to the intake manifold. On newer rigs there MAY be a third hose going to a solenoid valve/check valve that lets in fresh air when the engine is running (not sure what they did on newer rigs, but I have heard mention of a "Purge valve")

Got any photos of yours and the Vac lines?
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Quote=8Mud: "Go ahead and put up the best fence you can build, I'll bet on some Mexican with a few dollars of nails and a pile of scrap lumber."
34 MPG , '85 2WD Cherokee Pioneer with custom installed, 64 hp, 2.2 L Nissan SD22 Diesel 5 spd Manual; & 4 Renix XJs, '87 Wagoneer 4.0, 4WD, 89-Cherokee, 4WD, '87 Cherokee 2WD, & '89 Cherokee Pioneer 2WD, all 4dr. #2091
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