Planning to swap in a 3800 and deleted the purge solenoid....what do you do with the fuel tank vent line?....

Use the stock Fiero charcoal cannister with its vent line to the fuel tank and feed a vacuum line from the engine to it. The EVAP system is more matched to the car then the engine so just run the Fiero system. Dan

I'm doing an engine swap as well, and really wanted to clean up the engine compartment. I got rid of the cannister and all the plumbing. I ran the tank vent line up into the engine compartment and put a fuel filter on the end of it (stops crap from getting in and also minimizes fuel smell coming out). I'll tuck the filter up out of the way somewhere when I'm done. To be really safe, if you are concerned about rolling the car over and having fuel run out the vent, run it up and then back down low. I've done this on 2 other kitcars and it works fine.

Rick

Don't get rid of EVAP system! Saves gas. Stops a possible fire hazard or explosion.
See cave. Emissions

Do what FIEROFLYER said.


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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

[This message has been edited by theogre (edited 08-20-2009).]

quote Originally posted by theogre: Don't get rid of EVAP system! Saves gas.

I'm curious how it saves gas. If you hook it up without any solenoid, then the tank vent goes into the cannister and a vacuum line goes from the cannister into the throttle body or intake somewhere. From there the fumes go to the air filter and out into the air. What am I missing?

The raw fuel goes into the atmosphere and contributes to the green house effect. Your Canadian, check out the Montreal Protocal.

My understanding is that the fumes are burned by the engine through the vacuum lines...not released into the atmosphere by an air filter
I also believe that with a 3800 the air taken in through a vacuum line wouldn't go through an air filter in the first place...feel free to correct me if I'm wrong

Edit for clarity

[This message has been edited by GraterFang (edited 08-20-2009).]

quote Originally posted by Kekipi: The raw fuel goes into the atmosphere and contributes to the green house effect. Your Canadian, check out the Montreal Protocal.

Since we've just had one of the coldest July's on record, I'm sure that anything I do to warm things up a little will be appreciated.

I'm only offering a way of getting rid of the cannister if you want to clean up the engine compartment a little. If you don't like it for some reason, don't do it. Any car still using a carburetor (and there must be millions of them) basically vent the float bowl into the air cleaner can and then through the filter into the air. This is when the car is not running of course. I don't remember the old carbureted cars, without charcoal cannisters, catching fire or exploding more often than cars do now. In fact since cars now have 10X the amount of tubes, hoses, wire, sensors, ect, under the hood, there is more to go wrong and catch fire; I see more car fires now than when I first started driving (OK, I'm old!).

The fuel is burned by the engine, but I'm talking about when the car is off. If you hook up a vaccum line to the intake anywhere I think it has a path through to the air cleaner.

As far as saving gas, I doubt it is even measureable. How much gas could the charcoal cannister absorb (in fumes) with the car sitting for a few days? Maybe a teaspoon full of liquid at most?

Again, it is just an alternate way of doing things. I'll do it with my car since I don't want the ugly cannister. Am I polluting more than I should? Perhaps. But most of us are driving these old cars without cats anyways so.....what's that saying about casting the first stone?

Rick

quote Originally posted by couldahadaV8: The fuel is burned by the engine, but I'm talking about when the car is off. If you hook up a vaccum line to the intake anywhere I think it has a path through to the air cleaner.

I may be wrong but I believe many EVAP systems have a valve that by some various means (electric or mechanical) is only open when there is vacuum. I don't exactly recall but I think even the fiero EVAP system had this.

The canister vent valve is to release pressure built up by pumping gas.
Delete it and you will be able to pump about half a pint before it will shut off.
Don't do it.

The purge valve release's pressure that is built up while your driving.
It releases it into the intake tract/intake to be burned off in the engine.
This valve is normally closed,and only commanded open by the pcm when needed.
Your engine commands this,and know's when it does not happen.
There is a pressure transducer in the tank that tells the computer what's going on.
The computer know's when there is as little as a .020" hole in the system,and will flag it.
At keyoff,engine not running the purge valve will be closed,and yes it does need a certain amount of vacuum to enable.

Pressure buildup in the fuel tank isn't just dangerous,it will cause driveability problems and i've seen it cause fueling issues
on return system's and closed systems alike.

It also keeps these nasty fumes (emissions) from getting into the air that my kids and your kids breathe.
Don't be too surprised if you have those same fumes floating around your car while driving.
Mini truckers regularly delete these when they bodydrop/bag trucks and move their tank/fuel cell into the bed.

Most have issues from not doing it correctly.
If you do it,make sure you switch to a vented type gas cap,as yours is built for a sealed system.

Offhand,an OBDII vehicle will run it's evap tests either on a cold start (first thing in the morning) or after it has registered a
change in the sending unit of a certain percentage.
There also must be a a certain minimum amount of fuel in the tank for the cold start test to run.
So don't keep the car running while getting gas,the car will sometimes run the test during (from reading the fuel change) and flag the light.
Oh yeah,and it's a federal felony to remove those components.

Hope some of that info helps.

[This message has been edited by DefEddie (edited 08-20-2009).]

I just finished a v8 swap,I first had removed all the evap system including the exp tank.After reading about it on this forum i decide to reinstall all the evap system including the exp tank.
Mine is ran as follows
Line from exp tank to cansiter
canister to pvc valve
Vac to partial vac on carb
I think this is the correct way,Someone be sure to tell me if im wrong
So far its been fine

If you run the line from the expansion tank to the canister, will it use the canister as a filter or will it build up pressure?

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DefEddie... it's a federal offense to do a lot of things in this country, most of which are never prosecuted. Disabling EVAP in the OBD-II computer and using the Fiero's vacuum controlled system is perfectly valid. I didn't see anyone talking about plugging the hole.

couldahadaV8... carbs =

Kekipi... Rainbows, bunnies, trees...

There really is no good reason to not run an EVAP system of some kind. There is nothing to be gained by removing it. Just like the EGR, it serves its purpose rather transparently.

[This message has been edited by carbon (edited 08-20-2009).]

Seeing how the line from the exp tank from the factory came to the cansiter i think it still builds pressure.
Its going from you gas tank to the exp tank to the canister.
My understanding is the 87 's had the tank for extra fuel?
Im not sure so i put all mine back on,lol

Fiero has EVAP. Since 1973 all U.S. car has it.

quote Originally posted by couldahadaV8: What am I missing?

Look it up.
> Fuel tank can lose allot of vapor vs carburetor.
> Some carburetor did EVAP. Ford/Holly carburetor 2.5l cast iron did it for one. (Pinto/Bobcat, other.) Keep carburetor fuel vent close and not a EVAP purge to fuel bowl.
> Can lose a gallon in a month or two if weather gets hot. Some cars and most truck are worse.
> EVAP Canister can hold allot of vapor. Activated carbon, IE charcoal, make it work.
> Since 1973 no U.S. fuel cap will let out vapor. Keep it shut or EVAP won't work. (And if OBD2 then EVAP fail test.)

In old GM system 2 vacuum lines, 1 manifold and 1 port, connect purge valve. 1 line open valve and 1 line purges it. "Burn path" thru TBI/TB in Fiero and other.


Some solenoid system are purge valve control ECM/PCM only. But! OBD2 may be EVAP test too. Check if it has DTC "P" (P0455 P0442 etc) code. They test if it leak or gas tank cap is open.

quote Originally posted by GTCONVERSION: My understanding is the 87 's had the tank for extra fuel?

no. 87-88 mini tank is only for expansion. Fuel liquid should going in main tank. Should... Mini tank keeps liquid from EVAP Canister. Liquid fuel + EVAP = dead charcoal. Poison charcoal mean get a new EVAP canister. Really bad could cause a fire. Fuel leak out everywhere.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top of every forum page...)

[This message has been edited by theogre (edited 08-21-2009).]

Thanks Orge
So i have mine hooked up correct then?

Think so.
Main tank---mini tank---EVAP
Mini tank 2 line. Low line to main tank. Upper line to EVAP

OK Thanks

Get a Grand AM Charcoal canister. (Passenger side behind the front bumper) It has only two ports, one for the engine (electrical solenoid), one for the tank. Cleanest way to do a swap. IMO