Vented tank or pressurized with LS1?
Thread Starter
Teching In
Joined: Oct 2006
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Vented tank or pressurized with LS1? Do I need to run my vent to a purge solenoid and maintain some pressure in the tank to keep the ECM happy? There are only 4 wires coming out of teh factory fuel pickup assembly that I am using (from 2002 F-body) and I'm using an ECM from the same vehicle. I think the wires are: fuel pump power, 2 for fuel level and a ground, so I'm planning on running the vent line to atmosphere.
Im trying to come up with a solution as well. When I swapped into my 87, I built in the 4th gen evap lines and parts and figured it would work. Well...it wont work without the fuel level wire going into the PCM...and the aftermarket gauges wont work unless you disconnect the fuel level wire to the PCM. So...after I confirm that the EVAP system doesnt work now, I need to figure out what I can remove.
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
Originally Posted by 95GreenZ28
So you can vent it somewhere else besides going into the EVAP line? Sorry to bust into your post but I have been wondering the same thing. Then just haves the codes deleted?
Thread Starter
Teching In
Joined: Oct 2006
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I had Wait4Me Performance modify the ECM, but I'm not sure exactly what they did concerning Evap system. I've been running the tank vented to atmosphere since I put the car together and I'm already tired of smelling gas. I may try running a charcoal can and leave the purge solenoid fitting open. Does anyone make an aftermarket charcoal can?
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Originally Posted by jwbbuck
I may try running a charcoal can and leave the purge solenoid fitting open. Does anyone make an aftermarket charcoal can?
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Originally Posted by ghettocruiser
Im trying to come up with a solution as well. When I swapped into my 87, I built in the 4th gen evap lines and parts and figured it would work. Well...it wont work without the fuel level wire going into the PCM...and the aftermarket gauges wont work unless you disconnect the fuel level wire to the PCM. So...after I confirm that the EVAP system doesnt work now, I need to figure out what I can remove.
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
I would not vent the tank to the atmosphere if you can help it. The rate of fuel evaportaion will be higher in the summer and condensation will get into the tank easier during the winter.
Re'
Thread Starter
Teching In
Joined: Oct 2006
Posts: 27
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I don't have the purge solenoid and vapor pressure sensor controls in my ECM and I would prefer to not use the solenoid. I'm not sure how the EVAP system works on a non-computer vehicle. I assume the system purges only a low engine vacuum (WOT) and that the valve allows high tank pressure to bleed off when the fuel tank pressure gets high due to heat. I would not to avoid a potential vacuum leak and plumb the purge hose somewhere forward of the throttle body. Sound like a decent plan?
tanks were NOT just vented to atmosphere before EVAP systems. Pre-EVAP cars DO have a vent in the fuel cap, BUT it has a check valve in it so that air can come IN to the tank, but fuel vapors can't get OUT. This keeps your garage from blowing up, and causes the big WHOOSH you hear when you remove a properly-working fuel cap on an old car.
Launching!
Joined: Aug 2003
Posts: 252
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From: Down along the strand in NJ
I've installed the cannister in mine with all of the controls except the tank pressure sensor. What I did there was to in stall 2 resistors in series(2.2k & 1k), the 2.2k is connected to C2-46 and the 1k end to ground and with the middle tap connected to C1-64 the PCM is happy.
Hi 67pete
We're almost done with our swap of an LS1&T56 into a 1985 BMW E30 see
http://youtube.com/watch?v=2DbI3m6vs4Q
for our video of engine stuffing. So now its on to the wiring integration. We plan on using the fuel sender from the '99 donor Camaro, but not the fuel tank pressure sensor. We will use the evap canister, but are not sure about the evap vent valve. We will have the purge valve on the engine operational. We are hooking up to the stock harness connectors C220 and C230 for functions not directly on the engine. Did you go directly to C1 and C2 with your resistors, or to C220 & C230? Got any tips?
We're almost done with our swap of an LS1&T56 into a 1985 BMW E30 see
http://youtube.com/watch?v=2DbI3m6vs4Q
for our video of engine stuffing. So now its on to the wiring integration. We plan on using the fuel sender from the '99 donor Camaro, but not the fuel tank pressure sensor. We will use the evap canister, but are not sure about the evap vent valve. We will have the purge valve on the engine operational. We are hooking up to the stock harness connectors C220 and C230 for functions not directly on the engine. Did you go directly to C1 and C2 with your resistors, or to C220 & C230? Got any tips?
Launching!
Joined: Aug 2003
Posts: 252
Likes: 0
From: Down along the strand in NJ
I installed the evap vent tube back into the fill line on the high side, you probably could vent that out into the air...~
The resistors are in the harness near C1 & C2, as I'm slowly weeding out all of the wires I am not using.
The resistors are in the harness near C1 & C2, as I'm slowly weeding out all of the wires I am not using.
Originally Posted by ghettocruiser
Im trying to come up with a solution as well. When I swapped into my 87, I built in the 4th gen evap lines and parts and figured it would work. Well...it wont work without the fuel level wire going into the PCM...and the aftermarket gauges wont work unless you disconnect the fuel level wire to the PCM. So...after I confirm that the EVAP system doesnt work now, I need to figure out what I can remove.
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
A few threads on venting the tank, but nothing seems like solid solutions. Im about to redo my set up...and Ide like to leave the evap stuff out of the equation.
So...in a nut shell...Ill be watching this thread. haha.
Justin
all you need to do is put a resistor inline to the pcm so that it thinks the fuel tank is half full and your evap systems will work. let me know what year harness and pcm your using and i can be of more assistance
Originally Posted by fast98
all you need to do is put a resistor inline to the pcm so that it thinks the fuel tank is half full and your evap systems will work. let me know what year harness and pcm your using and i can be of more assistance
My harness and PCM and motor and fuel tank are all from a 99 Z28.
ANY help you can give me on that would be great!
Justin
You can also install a filter breather valve on a vent line from the tank. This will allow the tank to release pressure and prevent it from pulling too much vacuum. The valve will release under a certain vacuum or pressure. There is a filter on it to prevent contamination. This has been installed on my car for 6 months. I never have a fuel odor in my garage. This is the same valve that is listed in the tanksinc. install instructions. It is a gm part used on the side tanks for large trucks. 10033125 It's around $22.
TECH Apprentice
Joined: Jul 2006
Posts: 301
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From: Kansas City
Originally Posted by Rodder
tanks were NOT just vented to atmosphere before EVAP systems. Pre-EVAP cars DO have a vent in the fuel cap, BUT it has a check valve in it so that air can come IN to the tank, but fuel vapors can't get OUT. This keeps your garage from blowing up, and causes the big WHOOSH you hear when you remove a properly-working fuel cap on an old car.
It almost seems like its building LARGE amounts of UNSAFE Pressure in my old 1978 Caprice Fuel system, is this ok or hard on the Fuel system at all toe be Pressurize with such great amounts of Pressure ?
Should I remove the plug from the Purge Valve and will it help relieve some of the undue stress/pressure that is getting put on my 29 year old Fuel system ?
I have a 1978 Caprice 2 door coupe with a 98 LS1 Swap btw.
