We chose not to go with the evap system on my new 3800SC swap as it would be too complex having to use the solenoid controlled EVP canister, and the PCM needs a fuel tank pressure signal for the evap system to work properly. Thefore we scrapped the ide of getting the evap system functional.
Now the question becomes; what do we do with the gas tank vent tube. I am inclined to just terminate it at the air filter housing or hang it high with a breather on it's end, This way any fumes would be put back into the engine or just vented. Any other engine swap folks care to explain how they've handled the evap function.

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87GT 3.4 Turbo- 0-60 5.2 seconds
2006 3800SC Series III swap in progress
Engine Controls, PCM goodies,
re-programming & odd electronics stuff
" I'M ON THE LOOSE WITHOUT THE JUICE "

I will be doing something simmilar, and also to clean up the enginebay. It seems that just capping off the lines at the surge tank is a bad idea and that some venting is needed. Since the surge tank (87-88 fieros?) is at the right side I am thinking of putting some breather close to the tank, sealed to some flexible hose directed away from the (hot) enginebay and brakes. That way the filter stays high and clean while having some flexibility to the location of the 'outlet'....no idea if that will work
would like to see some solutions too...!

quote Originally posted by Dennis LaGrua: We chose not to go with the evap system on my new 3800SC swap as it would be too complex having to use the solenoid controlled EVP canister, and the PCM needs a fuel tank pressure signal for the evap system to work properly. Thefore we scrapped the ide of getting the evap system functional. Now the question becomes; what do we do with the gas tank vent tube. I am inclined to just terminate it at the air filter housing or hang it high with a breather on it's end, This way any fumes would be put back into the engine or just vented. Any other engine swap folks care to explain how they've handled the evap function.

My experience with OBD-2 PCMs is they will still operate the EVAP purge solenoid in the absence of the fuel tank pressure sensor and other related devices so long as the trouble codes for those devices are switched off in the PCM programming. I have done many such swaps and reprograms and in all instances the EVAP purge solenoid still operates as it normally would.

If you choose to remove the EVAP system from the car, as you may or may not already know you can't simply cap off the gas tank vent line -- the result would be a pressure buildup in the gas tank as the fuel is heated (either due to ambient temp changes or running engine). If you installed a breather filter on the vent line that would be ok, but a possible side affect could be a raw gas smell coming from the car as fuel vapors escaped from the vent when the fuel is heated.

I think you would be better off just installing the EVAP purge solenoid and charcoal canister and then just have the trouble codes turned off in the PCM programming for the other missing EVAP sensors and devices (don't forget about fuel level sensor codes if there are any).

-ryan

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power corrupts. absolute power corrupts absolutely.

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you would wire the purge to a switch...