My 1988 LFX F40 build. (Page 41/68)
Daryl M JUL 21, 01:59 PM
Next question,
I am running fuel lines from the tank. I assume the fuel feed and return go to this LS swap filter I got from Jegs, but I am not sure about the tank vent. I'm wondering if it goes to the device hooked to the intake , (see photos)? This is standard on the LFX motor, but I'm not sure what it is or what it does. Any help is appreciated.
Thanks,
Daryl
ChuckR JUL 21, 04:41 PM
The tank vent should go to the filler neck just like stock. This makes sure theair when fueling has a place for the air to escape, once that is blocked off when tank is full, is what makes the gas station pump automatically shut off from the increased pressure.

[This message has been edited by ChuckR (edited 07-21-2020).]

Daryl M JUL 21, 11:28 PM

quote
Originally posted by ChuckR:

The tank vent should go to the filler neck just like stock. This makes sure theair when fueling has a place for the air to escape, once that is blocked off when tank is full, is what makes the gas station pump automatically shut off from the increased pressure.




ChuckR
That is not the vent I am talking about. There are 3 lines coming convergence from the fuel pump/fuel gauge sender on is fuel supply to the engine, one is the return to the tank, the 3rd is a tank vent, right? That 3rd line is the one I am curious about.
ChuckR JUL 22, 07:31 AM
Yes that is the line I am talking about as well. It goes to the small vent line on the filler neck.


This is the Fiero Filler neck, the vent line from the tank goes to the small line on the filler neck.



This is the impala filler neck, it too has the vent line on the filler neck. so I am guessing that the vent line still would go to the filler neck and not to the EVAP.

I am not sure how to incorporate the EVAP system in this way, possibly do an EVAP delete? Or possibly try to Tee off the vent line? If you do not use the filler neck vent line it will need to be sealed off so that it is not a vapor release point / spill point.

[This message has been edited by ChuckR (edited 07-22-2020).]

ChuckR JUL 22, 07:58 AM
Delete

[This message has been edited by ChuckR (edited 07-22-2020).]

Daryl M JUL 22, 10:13 AM
ChuckR
I realize that there is a vent on the filler neck, but there is another vent . According to Guru, it goes to a charcoal canister. What I am trying to determine is where it goes from there and if the canister can be deleted and the vent can go directly to the device pictured. I think it is called a purge valve. The second photo shows the vent I an referring to. The first photo is the purge valve.
Will JUL 22, 10:29 AM
On '87's and '88's, the vent from the fuel tank is supposed to go to the expansion tank between the right frame rail and the right quarter panel. IIRC, there's another connection on that volume that goes to the filler neck vent and/or purge system.
ChuckR JUL 22, 10:32 AM
Yes that is the solenoid purge valve for the EVAP system, it does go to a canister.

I am not positive but the vent line should go in to this, have one line go to the EVAP solenoid, and one line go back to the filler neck vent. This is a guess, but the system needs to be closed. Or like I said above do an EVAP system delete, and when you have the ECU tuned have it ignore the EVAP codes and run the vent straight to the filler neck.
Daryl M JUL 22, 03:09 PM

quote
Originally posted by Will:

On '87's and '88's, the vent from the fuel tank is supposed to go to the expansion tank between the right frame rail and the right quarter panel. IIRC, there's another connection on that volume that goes to the filler neck vent and/or purge system.



Thanks for the info Will. Before deciding fieros were going to be my retirement hobby, I hadn't done much mechanic work since I was a teenager 45 years ago.
Rickady88GT JUL 22, 04:38 PM

quote
Originally posted by ChuckR:

Yes that is the solenoid purge valve for the EVAP system, it does go to a canister.

I am not positive but the vent line should go in to this, have one line go to the EVAP solenoid, and one line go back to the filler neck vent. This is a guess, but the system needs to be closed. Or like I said above do an EVAP system delete, and when you have the ECU tuned have it ignore the EVAP codes and run the vent straight to the filler neck.



I wish California had common sense laws regulating engine swaps,...but they don't.
I had to incorporate the evaporative system vent and purge on my LS4 swap. Basically I used a Monte Carlo evaporative system in the Fiero. Regardless of what the original Fiero had, it is now more like a 2006 Monte Carlo than a Fiero. No reprogramming necessary. For what it's worth, reprogramming is illegal on California engine swaps. Tuning is ok, as long as it does not interfere with emissions equipment. The car will still have to pass a smog inspection visually and run on the rollers with the diagnostic cable hooked up and tail pipe sniffer. Along with a fuel tank and cap pressure test.
It would be difficult to program the computer to cheat the inspection.