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89 evap/emissions help

C

chrslefty

NAXJA Forum User
Location
centeral phx az
ahhh...for every 2 steps forward = 1 step back ..
so i went to try and get my emissions done again..and i still cant get
the stupidf@#!N& thing to pass the gas tank pressure test ! every thing else is perfect .. but it (the tank)wont hold any pressure ?

this happened before .i tought that the problem was that when i
replaced the fuel pump i didn't get a good seal :it leaked profusely
when i filed it up ! so i dropped the tank and got the gasket on there
correctly and it no longer leaks any more ,and i also made sure that
the bottom was replaced on my evap canister and all of the lines were
hooked up .
so any thought on how to fix this ? or a way to cheat the smog police
so i can get my baby registered ? the hoa is getting pissed and calling
the city on me when ever i leave it in the drive way more than a day .

thanks for you help
chris
 
gas cap passed ,evap passed ..i think its just a visual on the canister.
the clamp one of the lines and pump air in to the tank and do a leak down test .that what it is failing.
chris
 
Just a couple of guesses, maybe the purge solenoid near the canister isn't sealing. Or the tank pressure control valve.
Where do they put the air in? If they are pumping back through the gas tank vent line, the tank pressure control valve could have popped. The gas tank vent steel tubing rusts through, the rubber connections rot.
If they are pumping air into the filler hole, the vent line has to be plugged near the tank pressure control valve. The pressure control valve allows the tank to equalize pressure (hot and cold).
 
Two holes in the gas tank I think. The other is where the filler pipe goes in. Maybe its not air tight any more?

First I heard of tank pressure tests. Hope they don't start those here.
 
wow hris, how are they testing up in phoenix? In Tucson they test the cap and pop the hood, half ass look in there. ( not like that bozo knows what he's looking at ) and then off to the tailpipe probe.
I would ask them what is causing that, they should be able to tell you what they are testing you on and your failing.
 
I discovered something new to me recently here in Houston, Tx on the emissions tests here. For OBD-II cars, 96 and newer, they do not do the tail pipe analysis and dyno tests. For OBD-I and older, like Renix they do the full tail pipe exhaust test with the dyno where they load the engine at various speeds and simulate climbing a hill under load.

For OBD-II, 96 and newer the Emissions test computer is connected to the the PCM (ECU) or on board computer and it checks for emissions codes, etc. If there are none, then they just look under the hood, test the gas cap, and their done.

Also, anything over 25 years old in Texas is entirely exempt except for the safety test. So 1981 and older vehicles are currently exempt here (for 2007).
 
From the 88 FSM
Evap.jpg
 
Wow, and 88 FSM still showing a carburator and only one fuel line.

There should be a return fuel line on there for the FI engine, and about 2 more vapor vent lines all the way from front to rear I think?
 
Ecomike said:
Wow, and 88 FSM still showing a carburetor and only one fuel line.

There should be a return fuel line on there for the FI engine, and about 2 more vapor vent lines all the way from front to rear I think?
Click to expand...

Nope thats all there is to the evap circuit, fuel return lines are not part of the evap system.

No carburetor bowl line, just a purge line.
 
Last edited:
AZRockRunner said:
wow hris, how are they testing up in phoenix? In Tucson they test the cap and pop the hood, half ass look in there. ( not like that bozo knows what he's looking at ) and then off to the tailpipe probe.
I would ask them what is causing that, they should be able to tell you what they are testing you on and your failing.
Click to expand...

dude i wish it was that easy ! i think that i need to find a different place ! but they are all the same . first they run you on a dino then you go forward and the hook you gas cap and plup into you tank and they pop your hood and pinch off a line and the machine dose the rest . thoes basterds wount tell me shit!i know that they are doing there job but they could trough a bone every now and then ! ill get it done tough !

hows the drive shaft working for ya?
 
Is there an electric or pneumatic (Vaccum) solenoid in the purge vent line that closes (normally closed) when the engine is off and opens when the engine is running? If so it could be stuck open!
 
Hey Chris, I am having the same problem. But my question to all is this...how is the tank supposed to hold pressure when there are two pressure relief valves on top? Those valves run to the canister. Then the canister runs to the air intake. There is no way that that system should hold pressure. I have failed twice now. I passed the emissions but keep failing that stupid pressure test. I took it to a shop, they said something atop my tank was leaking vapor, the grommets they thought. WRONG. I replaced those and still failed. I am Sofa King mad right now !
 
langer1 said:
What mike said one line controls a shutoff valve, it's closed when the engine is not running and opens when it is.
Click to expand...

John, can you elaborate? Sorry to be so dim-witted. Are you talking about the vapor vent hoses? Is there a shutoff valve in line with that system? If so, can you explain where? I haven't seen it, and there's no reference to it in my Haynes...? Either way, thanks for taking your time to help.

Also, I removed the canister. When I blow into it, air comes straight out the other hoses. Is that where the solenoid would be? My guess is no, there are no electronics running to the canister.
 
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