Alright its a SES problem fallowed with other problems. First off the codes are P0430 and P0440.

When the SES light first came on it was still running fine. I took it to advanced auto zone and they said bank 2 efficiency was low. So with 84423 miles on it I just thought it was the spark plugs and wires. So I got new ones but I havnt put them on (these things a ***** to change). But then the car starting hard. Itll crank for awhile and then itll start and you'll smell gas.

So while all of this happening I eventually run out of gas. So I go to fill up. Stick the gas nozzle in and try to fill up. The gas sprays everywhere! It wont let me fill up! its like something is stuck in there. so now im freaking out. I take it back home thinking someone has stuck something in there and is gonna screw up the whole fuel system. I get a coat hanger and stick it in there and go down a little bit and boom! a blast of pressure and gas drenches me. I didnt know it at the time but I now know our gas tanks are pressurized around 56-60psi. After this happens I think that maybe it was the pressure that wasnt letting me fill up. Well I was right. It filled up fine.

After this the car was running fine. No more cranking hard (maybe a little longer but hard to notice) and runs fine. SES light is still on though. Well I take it in to a local shop and have them look at it and tell them my story. They give me the codes (P0430, P0440) and see if theres kinks in the hose from the gas cap to the gas tank and check the fuel pressure. No kinks but fuel pressure is at 52psi so a little low but nothing big. prolly from the pressure blast I got. but anyway they dont know what to do since I brought it to them when it was fine.

So I dont know what to do. Im pretty sure itll just keep repeating. So what do you guys think? Ik theres something in the gas tank that regulates things (not the fuel pump). That could be it and ik itd help to change plugs. So what do you guys think? Thanks

 

well to make the codes go away (this works on my jeep...never got a code on my trans am) just take off the negitive side (black) of the battery and leave it off for a minute, this will reset your computer. then drive it for a bit and see if it comes back...as for the gas thing...u have a breather hole at the top of your gas tank...at least you should. is that clogged?

 

P0430 is most likely a bad passenger side cat. What year is your car? GM extended the warranty on the 00-02 LS1 F-cars to 10 years/120K.

P0440 is an EVAP code, large leak. Not a fuel pressure issue, first thing to check is the seal on the gas cap.

Visit gearchatter.com and see what the descriptions/diagnostics are for your year.

 

Its a 2000 Z28

 

P0430: bank 2 catalyst inefficient. This has nothing to do with engine performance, so a tune-up won't fix it. The converter on the passenger side has failed. Take it to the dealer to have it replaced free of charge.

P0440: general evaporative emissions system fault. One of the few DTCs I cringe seeing on a GM - all other manufacturers use much more specific evaporative emission system DTCs. If you're building pressure beyond a couple of psi in the tank, you obviously have a problem. Either the vent valve or purge valve is not working.

 

I'll take it to the dealership abou that converter. And you are sure its one of those valves?

 

About as sure as one could be diagnosing a car over the internet.

The only 2 components in an OBD-II evaporative emission system that could cause a pressure buildup is either an inoperative canister vent valve, or canister purge valve. And just because a valve is inoperative, does NOT necessarily mean the valve itself is at fault.

Take care of the converter first. Clear all the DTCs if the dealer does not do it for you. (MAKE SURE YOU TELL THEM YOU DO NOT WANT THE EVAP. CODE CHECKED!!) If the DTC returns then look into it.

 

Alright thank you I'll get on it and then let you guys know whats up

 

On my girlfriends '98 Cavalier P0440 went away after getting a new gas cap, even though the original looked fine. Got tired of clearing the code every week.

 

Where can i find a vent valve? I've been looking online and cant find anything. i found the purge valve though. its around $35

 

Vent valve is on top of the gas tank. It may or may not be available separate from the charcoal canister.

Don't throw parts at the problem.

 

I thought the vent valve was near the pass through wiring connector? Or is the canister vent valve something else?

http://shbox.com/1/fuel_pump_wiring.jpg

 

That is a picture of an OBD-I setup. That has a pressure vent to atmosphere. OBD-II cars have a solenoid vent.

 

Yeah I don't have one either, posted the pic because a guy on LS1tech was asking what it was on his '98, said he had one. Just before they changed the tanks so maybe that's the difference. OP stated he has a '00 - my bad.

 

oh ok so If its the vent valve that i need to buy. its called a vent valve solenoid? cause thats the only thing i have found