Evap Canister routing?
07-28-11, 08:36 PM
#1
Evap Canister routing?
I read before I removed mine that everyone doesnt have issues and that they just leave there lines vented and they dont have a hissing gas cap.
But that wasn't for 98+ that come with returnless fuel systems so setup might be different?
Just FYI I'm GTE and have my fuel return line dumping right before the tank with a fitting in the filler neck. Anyway my issue is now that I have it removed and the lines are vented my cars acting up. Under light throttle or if I let off the gas and come back on the gas lightly my widebands reading 17-18 a/f's for a couple seconds then goes back down to normal 14.7-15.6
Only thing I can think of is that I need some sort of pressure in my tank to make this setup work. Mid throttle and WOT are awesome. Its not the biggest issue but I'm **** when it comes the things running perfect. I even tried increasing base fuel pressure to 50psi but that only really affected wot #'s.
Any help would be great
But that wasn't for 98+ that come with returnless fuel systems so setup might be different?
Just FYI I'm GTE and have my fuel return line dumping right before the tank with a fitting in the filler neck. Anyway my issue is now that I have it removed and the lines are vented my cars acting up. Under light throttle or if I let off the gas and come back on the gas lightly my widebands reading 17-18 a/f's for a couple seconds then goes back down to normal 14.7-15.6
Only thing I can think of is that I need some sort of pressure in my tank to make this setup work. Mid throttle and WOT are awesome. Its not the biggest issue but I'm **** when it comes the things running perfect. I even tried increasing base fuel pressure to 50psi but that only really affected wot #'s.
Any help would be great
07-29-11, 11:01 AM
#2
*Update put canister back in and it still doing it... Only other thing I did when I removed it the first time was add a bigger fuel filter (300zx) and turn the boost controller up a couple turns, this doesn't make sense.
Now I'm leaning towards fuel pump dieing? or maybe injectors? Hard to say because mid/full throttle are perfect.
Now I'm leaning towards fuel pump dieing? or maybe injectors? Hard to say because mid/full throttle are perfect.
07-29-11, 01:26 PM
#3
my car used to run lean exactly like yours when excessive pressure built up in the tank (AEM settings have the canister purge off by default), mostly noticeable at idle really. If I popped open the gas cap, mad pressure would come out almost spraying fuel, and the AFR's at idle would return to normal.
when I corrected the settings all was well, and later when I deleted it I just vented the line with a fuel filter inline and there was no change, but no pressure can build up in the tank now so afr's are very consistent.
Im not so sure about returnless systems, or what you have changed it to, but if you have an unnormal amount of pressure when you open the gas tank, then something is wrong and pressurizing the system, and in my case it was the extra pressure causing it to run lean, not rich. also make sure you capped off that vacuum hose that goes from the canister to the intake manifold. hope that helps
when I corrected the settings all was well, and later when I deleted it I just vented the line with a fuel filter inline and there was no change, but no pressure can build up in the tank now so afr's are very consistent.
Im not so sure about returnless systems, or what you have changed it to, but if you have an unnormal amount of pressure when you open the gas tank, then something is wrong and pressurizing the system, and in my case it was the extra pressure causing it to run lean, not rich. also make sure you capped off that vacuum hose that goes from the canister to the intake manifold. hope that helps
Last edited by Ali SC3; 07-29-11 at 01:29 PM.
07-29-11, 04:32 PM
#4
Ali SC3 my car used to run lean exactly like yours when excessive pressure built up in the tank (AEM settings have the canister purge off by default), mostly noticeable at idle really. If I popped open the gas cap, mad pressure would come out almost spraying fuel, and the AFR's at idle would return to normal.
when I corrected the settings all was well, and later when I deleted it I just vented the line with a fuel filter inline and there was no change, but no pressure can build up in the tank now so afr's are very consistent.
Im not so sure about returnless systems, or what you have changed it to, but if you have an unnormal amount of pressure when you open the gas tank, then something is wrong and pressurizing the system, and in my case it was the extra pressure causing it to run lean, not rich. also make sure you capped off that vacuum hose that goes from the canister to the intake manifold. hope that helps
when I corrected the settings all was well, and later when I deleted it I just vented the line with a fuel filter inline and there was no change, but no pressure can build up in the tank now so afr's are very consistent.
Im not so sure about returnless systems, or what you have changed it to, but if you have an unnormal amount of pressure when you open the gas tank, then something is wrong and pressurizing the system, and in my case it was the extra pressure causing it to run lean, not rich. also make sure you capped off that vacuum hose that goes from the canister to the intake manifold. hope that helps
Ya I understand what your saying. And my Evap canister has 3 lines that are supposed to go to it but after the swap only the gas tank vent still went to it. Only reason why I re installed the canister today is because I read on some other cars the tank needs to see like a 3psi in there. So I guess I'll just remove it again and throw a filter on the end. Now my return line question was I wasn't sure if the return needed to be in the bottom of the tank (the fitting in fuel) would cause a little better pressure at the fuel rail. I bought a kit where you cut the filler neck on the gas tank and its got a nice fitting and you sandwich it in there.
So Now I'm not sure why I'm getting the slight lean reading at low throttle. Maybe it will just go away
07-29-11, 05:52 PM
#5
Ugh I dont get it. I just removed the Evap again and turned the boost down and its still doing it.. I just don't get how this randomly started happening.
All I did basically was change out the fuel filter to a bigger one (300zx) and added the cold air intake I mean if I come to a dead stop the rpm's will fall due to 17-18 af/rs, then it slowly picks up and idles 15.4-16.0. And part throttle only (feathering the gas) or just light cruising. it goes 17 ish a/f's car feel like it hits a dead spot for a second or 2 then the moment you start giving it more gas it will correct and back normal?
All I did basically was change out the fuel filter to a bigger one (300zx) and added the cold air intake
I mean if I come to a dead stop the rpm's will fall due to 17-18 af/rs, then it slowly picks up and idles 15.4-16.0. And part throttle only (feathering the gas) or just light cruising. it goes 17 ish a/f's car feel like it hits a dead spot for a second or 2 then the moment you start giving it more gas it will correct and back normal?
07-30-11, 10:03 AM
#6
Today I went threw it and checked all my flanges etc all tight, checked vac lines. I did find a bad line to the WG had a hole in it so I replaced that. 'Took it for a spin it started off ok then it was back to doing the lean situation on low throttle
. Then I disconnected the CAI I made, so it would be sucking hot air again, but it still happened.
It sounds stupid but the only thing I can think of now that is causing this is the bigger fuel filter I installed. Its atleast twice as big as the one I used to have..I might have to change it back since that's really the only thing left I messed with.
Heres a vid, towards the end you'll see what I mean
http://www.youtube.com/watch?v=EvFsrw3TwR0
. Then I disconnected the CAI I made, so it would be sucking hot air again, but it still happened.It sounds stupid but the only thing I can think of now that is causing this is the bigger fuel filter I installed. Its atleast twice as big as the one I used to have..I might have to change it back since that's really the only thing left I messed with.
Heres a vid, towards the end you'll see what I mean
http://www.youtube.com/watch?v=EvFsrw3TwR0
Last edited by SC51; 07-30-11 at 03:00 PM. Reason: added vid
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