failed FUEL EVAP TEST on CA smog test

[eerrrrr]

1991 240sx w/98 ka24de. only fuel mod is a 255 pump.


so i guess CA pass this law where they check our fuel evap system in dec 07. well i failed that (passed everything else though). i took it home and checked the fuel evap lines (according to the FSM, its the lines that go into/out of the carbon canister). i traced it back to the fuel tank also, but dont know where it connects to because it is no longer visible. both hard and soft line looks good, but maybe its something hard to see. i didnt notice anything wrong with the lines, no loose lines, no cracks, no nothing. so i was just wondering how the hell i would test this? smog diagnose will be 112.00. any chance when the dude replaced the fuel pump, he had to disconnect some of the fuel evap line? any help would be great.

[brndck]

try replacing the lines to/from your carbon cannister. they're just vacuum lines so it should be cheap. and maybe use hose clamps where they connect to the fittings to make sure you have a good seal.
cali smog is lame.

[Neejay]

Wow, I hope they don't start doing that here...I just removed mine.

Do you have a FPR since you got the 255 fuel pump installed?

[johngriff]

How exactly did you fail? The lines are clogged most likely.

When installing the fuel pump, the evap lines don't go close to the sending unit, so it probably didn't get messed with. I think there is a way to clean the cannister, but I can't remember offhand.

[eerrrrr]

i failed because they detected a leak. they do a low pressure test to see if the vapor lines have a leak. and if they do, then u will fail. according to the smog tech, he say its a huge leak, enough for me to be a gross polluter. its a small part listed under the FUNCTIONAL TEST. i did a quick search, and this is what it is:

http://www.atestonly.com/index.html

so yeah i dont know what else to do. is there a way i can pump smoke into the gas tank to detect a leak, because this test can be done when the car is off also.

[pbcstylez]

wait was this the gas cap test? (sorry if i sound retarded its been awhile since i last smogged anythign)

[tknbkthrsdy4anfg]

Originally Posted by pbcstylez

wait was this the gas cap test? (sorry if i sound retarded its been awhile since i last smogged anythign)

Nope, they test your car now.

[drftwerks]

no its a new thing they are doing, actual leak test, at least a .0060 hole

[GSXRJJordan]

^^^ My first instinct was gas cap also... I'd replace it anyway.

Like John said, try replacing the vacuum lines to and from the canister first. Changing fuel pumps wouldn't mess with the evap system, unless possibly the o-ring wasn't put back in correctly.

[eerrrrr]

yeah its on the car like theyve all mentioned. they stick a thing in the gas tank to replace the gas cap and pressurize the tank to allow the fuel vapors to enter its path to the cc.

does the carbon canister sposed to have a big tube connected on the bottom that vents to the frame? if so how come it dont show on the FSM.

[johngriff]

yeah thats the end vent for it

[eerrrrr]

damn i just need to find a way to put smoke into the lines and ill know/find the leak. anyone recommend anything? im sure thats how they'll diagnose it too.

[brndck]

ya but its effing expensive.
http://www.redlinedetection.com/
we had one at the smog shop i used to work at. if you know anyone who works at a smog shop they might be able to hook it up.

[bo2o]

ya its new. new to the smogger too, and cost alot for that machien.

i remember with the car on you can blow smoke in areas and you can kinda tell wen the smoke is being pushed or sucked in...

there should b away to bypass this system. just havnt found out... mayb you can pump the tank and juss pinch all the lines or sumthing.... haha

[eerrrrr]

yeah thats what i was thinking about doing. there are 2 soft lines at the end of the hardlines, one from the gas tank, and one to the cc. i was planning on capping off the line from the gas tank. if i still fail, i know its something back there instead of up front. but i dont want to do this cuz i get a free retest. if i dont pass the free retest, ima have to pay another 50 or so bucks for smog test, and the diagnose also.

ok nevermind about capping off the lines. i just looked at the vid of how u use that smoke pro thing for the evap and i dont think i can just cap off the lines. it first checks for the flow of it first. if i cap it off, there would be no flow.

[frankist]

it only checks for leaks, the canister has nothing to do with it, we clamp off of the lines before it hits the canister, make sure your fuel evap lines going back into the tank arent leaking, and that all clamps are tight.

[eerrrrr]

so when u "clamp off the lines before it hits the canister" did u plug it up or did u just tighten previous clamps on there. if u did clamp it off, did u pass the test?

[frankist]

when you evap test, you use locking pliers to clamp off the line right before it hits the canister up front or where ever it is depending on the car. so pretty much you have to make sure you dont have any leaks from the gas tank to your evap line.

[frankist]

up front for your car. msg lenth wooo.

[eerrrrr]

do u guys think doing this will help me pass? if it dont pass, ill know that its somewhere in the back maybe? ive been reading lots and it seems like detection of a leak is due to loss of pressure when pressurized. so if this helps keep pressure (blocking path with something), would it be a way around the test? i need SMOG TECH helps.

[frankist]

that would be one method of pinpointing whether it be the tank or the lines, but your best bet, is to use a smoke machine. rent one or just go to a shop. =) fix the problem

cheers.

[eerrrrr]

im trying to avoid going to the shop because it cost 112 just for a diagnose. they said ill be charged 1.5 hours. if i had a way to put smoke in the lines i would, but i dont. i was planning on renting a fog machine and doing something with that, but i dont know where to rent one at.

that idea up there is an attempt to "cheat" passing smog.

[drift freaq]

Usually the big offender is your vapor return line from your filler neck. If I remember correctly my smog guy was telling those crack on a lot of cars.Until now it was not a big deal. My smog guy was also complaining about this new reg. because it cost him a lot of money to purchase the fuel evap test machine.
Somone in the Sacremento got this idea that this would help reduce emissions . Meanwhile diesel trucks and ships are spewing more particulate matter here in socal than automobile.

[eerrrrr]

ill check that this weekend. i have till next friday until my free retest is expired. its too early to find a way around it huh?

[eerrrrr]

damn i check the whole vapor line back to the fuel tank. everything "looks" good. from my view, all rubber hoses were in the right places and where clamped in good. the hard line looked good also. the line from the fuel neck looks good also. i guess im just going to have to bring it in to them because i have no way of testing the lines with nitrogen....

[mr.lonelys12]

i dont know if this is a good idea but you could try pumping propane into the system and use a propane sniffer thing to detect where your leak is at. that might help?

[burnsauto]

when they did the fuel pump...was the o ring replaced with a new one..or the old one cut and made to fit. that could be your leak..

[eerrrrr]

i dont know. i guess ill take the pump out and see.

[91redMS13]

how did they actually do the test? Did they actually put an air test thru the tank?

[eerrrrr]

that link i posted tells u what they do. they pressurize the tank with a non-combustible gas (nitrogen is what a lot of ppl use--or anything that wont cause an explosion under pressure with fuel vapors--shop air/regular air contains oxygen so it will explode under pressure mixed with the fuel vapors). i guess that thing is hooked up to a gauge which replaces the gas cap and lets in/tells them the pressure. if the pressure holds for x amount of time, then it passes. if pressure drops, then there is a leak. your leak depends on the speed of dropped pressure. there is a max pressure u can drop. im still not sure if the machine knows if its going through the evap system. im not even sure if they can test for that.