EVAP System Without Pressure Sensor
Thread Starter
Teching In
Joined: Mar 2018
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EVAP System Without Pressure Sensor I am trying to figure out a way to utilize a more basic EVAP system for my Jeep TJ LS swap. Am I able to run the EVAP system without the use of a gas tank pressure sensor? Is the sensor only there to make sure its not leaking or does it have something to do with activating the purge and vent solenoids?
The TJ does not have any port for the sensor so ideally if I can avoid using it and still have a somewhat functioning system. I do not live in a emissions check state so I am not worried about having it 100% functional as if its still on the truck, just want to keep fumes down when driving no doors no top.
The TJ does not have any port for the sensor so ideally if I can avoid using it and still have a somewhat functioning system. I do not live in a emissions check state so I am not worried about having it 100% functional as if its still on the truck, just want to keep fumes down when driving no doors no top.
How is the tank vented? I don't see any reason why you couldn't run a charcoal canister from a 70's 80's vehicle and connect your tank to the inlet side and connect the outlet side to the intake manifold to send the fumes thru the engine. I think Michael Yount? uses something like that on his LS3 Volvo if i recall correctly. Try and find his build thread on here or try contacting him through PM.
Thread Starter
Teching In
Joined: Mar 2018
Posts: 23
Likes: 2
How is the tank vented? I don't see any reason why you couldn't run a charcoal canister from a 70's 80's vehicle and connect your tank to the inlet side and connect the outlet side to the intake manifold to send the fumes thru the engine. I think Michael Yount? uses something like that on his LS3 Volvo if i recall correctly. Try and find his build thread on here or try contacting him through PM.
Talking with one of the facebook groups I supposedly could hook it up as if it were in a Silverado and just omit the pressure sensor and tune out the CEL for it, but the purge and vent will still work.
TECH Fanatic
Joined: Feb 2015
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Sensor not used for evap control just emissions leak check. You could run like factory as mentioned in fb group with pressure delete. If you wanted tank pressure mgt, tee into a tank vent line assuming tank connection does not include check valve.
Last edited by tblentrprz; Feb 27, 2021 at 07:48 AM.
I researched it a number of years ago and ultimately decided it was beyond the scope of the course. So PSI Conversions turned off the related (purge valve) functions in the ecu they set up for me. And as mentioned above, I plumbed the charcoal canister into the air inlet tube upstream of the maf sensor. Beta test going on 5 years without a hiccup.
I researched it a number of years ago and ultimately decided it was beyond the scope of the course. So PSI Conversions turned off the related (purge valve) functions in the ecu they set up for me. And as mentioned above, I plumbed the charcoal canister into the air inlet tube upstream of the maf sensor. Beta test going on 5 years without a hiccup.
Andrew
"So PSI Conversions turned off the related (purge valve) functions...." They turned off that function and I removed the valve and capped the connection. Where the charcoal canister previously connected to the purge valve -- I simply relocated that hose to a barbed nipple installed in the air inlet pipe upstream of the maf - so that anything pulled from the canister gets metered.
"Is your gas cam sealed or venter?" Hmmm....autotype I guess -- assume that means 'is your gas cap or tank sealed or vented'? All tanks are vented in some manner -- or the constant removal of fuel would eventually crush/buckle the tank. There is a vent in my filler neck that's designed to help keep the gas dispenser from overfilling the tank. The tank is also vented through the charcoal canister. Last - the gas cap will both let air in and pressure out if it exceeds the light spring in the venting mechanism.
"Is your gas cam sealed or venter?" Hmmm....autotype I guess -- assume that means 'is your gas cap or tank sealed or vented'? All tanks are vented in some manner -- or the constant removal of fuel would eventually crush/buckle the tank. There is a vent in my filler neck that's designed to help keep the gas dispenser from overfilling the tank. The tank is also vented through the charcoal canister. Last - the gas cap will both let air in and pressure out if it exceeds the light spring in the venting mechanism.
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TECH Resident
Joined: Apr 2007
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From: Montgomery (Lake Conroe,) TX north of Houston
Andrew and I have been discussing this very topic concerning my LS swapped Foxbody coupe. I've got the entire OEM Ford EVAP system out of my donor car (1991 Mustang GT) but we're trying to figure out how to make the Holley Dominator control it.
