Is the evap system that crucial that it cannot be simply corrected with a vented gas cap? Is it worth keeping? Right now if i don't have to run an extra line underneath the car I'd like it, so that's why i ask, is it actually worth keeping around? I've got all the parts and the only expense to me is the lines, and then i can wire it into my pcm. Past that it's just time to me, so please let me know if i should keep it or let it be gone.

Basically I don't want to lose MPGs if it's such a simple system to implement. Also, is getting a vented gas cap as simple as walking into Advance Auto and asking for one? Thanks in advance.

 

I run the EVAP system to make sure I dont smell gas like with a vented cap. You will have to keep the EVAP solenoid anyway unless you program it out.

 

I'm running a '94 Harness and PCM with a manual transmission/94 Fbody tune as my baseline, so i'll be tuning out the egr, vats, and at least air in the PCM. Killing one more code in the PCM won't be hard, but how bad is the smell of a vented cap? I mean is it going to contantly smell like I have a gas leak or what? Anyone found a smaller evap canister to run? Thinking about relocating a canister to the back somewhere and just have a vaccuum line run back to operate it.

 

If your keeping the Third gen tank, keeping it is 5 times easier then deleting it. Just hook up the vacuum hose from the canister to the purge sol. with the factory line. Its that simple.

 

Alright, I guess I'll run the new lines, seems like it'll work out for the better, I like not smelling gas, bad enough after i fill up i can't part on steep grades or my gas tank will start to poor out the spout lol. Thanks for the input guys.

 

I didn't keep mine. It was easier and made a ton more room in the bay for my CAI and relocated battery (relocated to pass side like a camaro). CAI now sits where the batt did originally.

 

Yea i'm going LT1 with a 4th gen radiator bottle so battery has to stay on the passenger side of my bird, so i've got room for my intake, but just figured, i've seen enough muscle cars at shows, and the only fuel i smell usually was from their exhaust cause they hadn't a clue how to tune a carb because so-n-so put it together for them. Never really noticed that much of a smell with vented caps of older cars, but i've seen all the cars drptop70ss has and i'm sure he's seen enough vented caps in his day to make a reasonable judgement on the amount of smell with his swapped LT1s.

How much of a smell of fuel do you get Thirdgen89GTA?? And did you swap to a vented cap? Just curious what the little vent in the back was for if the evap system seems to do the same with letting go of excess fuel pressure/vapors.

 

No idea. I occasionally smell a little gas odor, but that could be due to my leak #8 primary as well. Otherwise I almost NEVER smell gas. I kept the vent on the rear of the tank, but the front line is gone.

I'd post a pic of my bay, but its DIRTY and messy. I need to do a better job with the PCM wiring harness.

 

Yea, my harness will hopefully come out clean and neat, in the process of looming that up as we speak. Should work out pretty nicely and concealed.

 

I have had vented tanks that were fine outside, but when parked in a garage smelled pretty bad. Also depending on air flow I have had the smell come back into the car at speed if the windows were down, especially in the summer heat. The evap system is pretty simple to run and there is no real gain to be had removing it so I use it. You can always try leaving it off but you may not be able to find a vented cap that will fit your tank, I dont think vented caps have been used since the 60s. I know my 70 chevelle has a vapor canister and non vented cap.

 

Hmm, excellent point, thats why i was curious if i could just walk in and ask for one if they were made as universally as most caps. And yea, seems easy enough to keep, just figured i'd throw it out there. Next will be to see if the '94 pcm can control my '88 evap purge solenoid to make my life that much easier. Thanks guys.

 

for the record third gen vented gas caps are on ebay for less than 20 dollars. the previous owner on my car removed the canister so i chucked the whole setup in favor of the vented cap. filtered the vent line off the tank and done.

~Steven

 

Well thats just my concern is I keep my car in a garage most of the time which is right below my house, so if fumes are going to fill the garage when i park it, then the fumes will also make their way upstairs where i don't want them, so I'm kinda narrowed to keeping the evap system, which like i said wasn't a big deal, just didn't understand why we have a pressure valve/vent in the back and needed the evap system to vent fumes when the pressure becomes too much into a canister. Thanks for the insight, but I think i'm going to be using the canistor in a remote location somewhere in the front end.

 

The whole reason behind an evap system is to re-route raw fuel vapors (HC) too the manifold so the are burned and hopefully all turned into CO2. The reason behind the factory vent is so the tank doesnt implode when the sol. pulls a vacuum on the canister, or bubble out on a really hot day. All tanks have some kind of vent.

 

What if I swapped in the 4th gen tank? Would that eliminate all the evap stuff under the hood?

 

Im not sure, I kept my 3rd gen tank so I couldn't tell you. I just used the purge sol. on the LT1 and hooked up the hose coming from the canister to that. Then the other hose coming off the purge sol. goes too manifold vacuum.