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How-To: Bypass Charcoal/EVAP canister VIII/IV

Old May 12, 2017, 12:33 AM
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How-To: Bypass Charcoal/EVAP canister VIII/IV

So I was reading this thread:

I was looking on what needed to be done to Bypass or Remove the Charcoal Canister to remove weight. How ever, I wanted to keep EGR because my logs show with it running, I gain around 2 to 3 MPG using it. Of course it is tuned for my set up. So I didn't like the outcomes and solutions suggested in that thread. So I decided to customize a solution that will work with or without the EGR. Here is what I came up with:

EDIT:So the Purge Valve will need to be tuned with this setup. Will post it up, once I can play with it. Right now, no codes on fresh ignition, but if car has been run for a while, and then shut off, and then restarted any time within 2 hours, and CEL/DTC P0441 shows up. Which is an Error in Purge.

OLD SOLUTION:Good / New method: Remove everything in this diagram except 15, 4, and 12. connect 4 and 12 with a 17mm barrel (one is 16.5mm and one is 17.5mm). Cap the hose for connection #3 with a 12mm cap. Note that if you do not do this there will be limited access to your fuel system via connection 2.
Bad / OLD method: Remove all of this diagram after hose #7, and plug hose #7 with the check valve from the front of the car.

Optional: Remove the hard line (#7) that runs from the rear of the car to the front of the car. Note: you will have to un-bolt the fuel brakets along the underside of the car and the line does not weigh very much.

Optional: The check valve might be useful if you will be removing the charcoal canister as it will allow vapors out while letting nothing back into the fuel system (at connection #2 above). Unfortunately it is much smaller then this connection and the valve may become stuck closed and clogged if left open to air in a dirty environment, but this may be better than whatever clogged it having limited access to your fuel system. Please note the check valve is represented backwards in the image shown above, as well as some of the other FSM diagrams.
MY Solution: So I have a Question and a Theory:

Since it looks like in the photo below, both 11 and 12 connect as an input to the charcoal box, and 7 exits into connection 9(solenoid), which is connected to an over glorified air filter(Numbered 8), which then has two exits (3 and 4) which connect to 15.

Why can't I put a check valve in connection 11 and 12, and then tie them both together and input them both into connection 9(solenoid) and then utilize the over glorified air filter(Unit 8) as normal? I am trying to keep the EGR for fuel economy, and just want to ditch the charcoal canister. My EGR is tuned with everything else. This keeps the periphery bits and ecu settings close to stock on the setup allowing the purge valve to work, of which, I have the ability to tune as well. Just wish to ditch the charcoal like I said.
DO NOT PUT A CHECK VALVE IN THE EGR HOSE!!!! My first attempt set off an "EGR LOW FLOW" DTC. I know why. There is a plastic check valve behind the block on the Intake Plenum. It is very low pressure, and has very minimal output. IF YOU PUT THE CHECK VALVE INLINE A THE REAR IT CAUSES TO MUCH BACK PRESSURE ON THE ORIGINAL CHECK VALVE. LEAVE THIS ON OUT. I HAVE EDITED MY FIX, WITH PICTURES.

So how do we go about this.

(1) Ft. 3/8" or 7/16" Fuel Line. Local Auto Parts Store $2.00
(1) Ft. 5/8" Fuel Line. Local Auto Parts Store $2.00
(1) Heater Hose "T" 5/8" Hose; 5/8" Hose; 3/8" Hose. Local Auto Parts Store $7.50
(2) 5/8" Hose Nipple with 1/2" Pipe Thread. Local Auto Parts Store $5.30 x 2
(1) 1/2" Check Valve with both ends 1/2" Pipe Thread. Had to go to Local Kenworth/CAT/Diesel Store $21.25
(1) 1/2" Pipe Thread Union. Kenworth/CAT/Diesel Store $3.50
Various Pipe Thread Tape.
Various Zip Ties

Various 12mm Sockets, extensions, and Ratchet
Hammer or Manipulator
Pry Tool, Screw Driver, or Persuader
Hack Saw or Saws-all
Razor Knife and Dikes
Jack and Jack Stands

Step 1:
Jack Car up, and rest on Jack Stands

Step 2:
Disconnect electrical connection to the Purge Valve. Disconnect Hoses 1, 2, 3, 4, 7, 11, 12 from car. Try to save them for they are reusable, and some of the formed corners will come to an advantage later.

Step 3:
Unbolt Charcoal Canister and Assembly from bottom of car utilizing 12mm Socket.

Step 4:
Locate the divide between Charcoal Canister and Air Filter Assembly.

Step 5:
Utilize Hammer or Manipulator, and Pry Tool, Screw Driver, or Persuader to start wedging it apart.

Step 6:
Once you can notice the tiny weld points start to stretch, cut welds with Hack Saw or Saws-All.

Step 7:
Once you have two parts, the Air Filter Assembly is what we want to keep, and it should be bolt-able back to the car with the factory two mounting points.

Step 8:
Cut a 2" section of 5/8" hose of and connect to the Purge Solenoid.

Step 9:
Utilizing the 5/8" Tee, shove one of the 5/8" Nipples into other end of 5/8" hose connected to purge valve. Zip Tie or clamp. Check orientation of Tee union so that the 3/8" Nipple is pointing to the output of EGR nipple or connection 1 on underside of car.

Step 10:
Utilizing the hose that made connection 7 to 9, cut your self a right angle piece out of it. Leave your self a good 1 and 1/2" on either side of the 90 degree bend. Shove this hose on to the other end of the 5/8" Tee and orient it the same direction pointed at connection 2 on underside of car. Zip Tie or clamp this connection.

Step 11:
Bolt Air Filter Assembly and current mock up of hoses up to the bottom of the car. Plug in Purge Valve connector.

Step 12:
Build or Make Check Valve Assembly for Fuel Tank Breather. Use Pipe Thread Tape to seal all connections. The 1/2" Check Valve will be about 4 to 5 inches in length.
Blow through to get orientation of flow.

Step 13:
Checking orientation of flow with check valve, connect output of check valve into hose you just connected to the Air Filter Assembly. Connect and Zip Tie or clamp.

Step 14: Cut and Connect 5/8" Fuel Line to finish the connection to the Check Valve you just installed. Cut 3/8" or 7/16" Fuel line and connect EGR output to 3/8" nipple.
Clamp or Zip Tie Both ends of those connections.

Step 15: Marvel at your work. Lay there and admire yourself.

Step 16: Crawl out from under car, Start car, and check for leaks.

Step 17: Assuming no leaks, Jack car up, pull out Jack Stands, and then let car down on the floor.

Step 18: Crack open Beverage of choice, and cheers your tools. You completed the project. Atta Boy... or Girl.

Last edited by Raceghost; May 16, 2017 at 10:54 PM.
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Pirana (Feb 19, 2019)
Old Mar 11, 2019, 01:04 PM
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Came accross this as I had some questions...

my my egr and canister have been removed from the car.

and I always wondered if this could cause my ethanol to go “stale” attract water prematurely du tot eh gas tank vent

should I look into adding a check valve to that open vent?

i have the other line blocked off with a “cap”


I’ll have to get a picture of what I am talking about. May help.
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