no1kicker

iTrader: (4)

I am swapping a 5.3L into a 91 Trans Am which was TPI. I am using a 99-02 f-body pcm and sensors. I want to keep the charcoal canister functional.

The PCM has a pin for canister purge and also canister vent, but it seems like it relies on input from the fuel tank pressure sensor to work. I was wondering if anyone had a solution to keep the canister. Do I need to use the LS1 fuel tank pressure sensor?

bczee

iTrader: (12)

You are correct on the sensor on the fuel tank.. The PCM will need that imput to activate the EVAP.

you can try mounting the sensor one in the sender plate with a rubber gromlet ..

Another post said that they just used one of the vent lines with some rubber hoses and clamp the sensor into the hose and connected the harness.. and the rest of just installed as it should be.

I just used my Chevelle Canister, did away with the LSx EVAP setup. used the vacuum port to the canister and it was setup as normally would be for my Chevelle.

jslezak83

Greg, hows that swap coming along? For my S10, I'm going to use the factory canister as BCZEE described. The 1st gen S10 canister is the same size as your F-body one, except there is no purge valve on top. On these trucks, there was just a vacuum line to the throttle body. Maybe that might help ya in finding a solution.

classic79

What or how does the evap work on the lsx motors. I looks like it is a a vacuum source in the intake, put there is an plug on it.

If going like jslezak83 says could you still use the ls evap port and line or just cap that and route to the intake tube after the airfilter or another ported vacuum source.

flame

iTrader: (13)

I'd have to check to be 100% sure but on my swap the canister purge is functioning without the vent solenoid or pressure sensor. The pressure sensor and vent are used to test for leaks but as far I know they are not used for purge operation at all. I'll have to check my logs at home to see whether the purge is commanded during cruising. Somebody above said about hooking it in without the purge solenoid which would work but then the A/F would go rich because the pcm would not know about the extra fuel going in.

69 Ghost

I have a thirdgen sending unit/pump setup in my car and I was planning on using the evap. If you put a tee in from the top of the tank to the pressure sensor then to the evap cannister you will have the same setup as the 4th gen.

no1kicker

iTrader: (4)

Thanks for the replies guys. I think I am going to try and not use the pressure sensor, and maybe get an S10 canister to make things easier.

The swap is coming along well, I'll create a thread here when I'm done. This wiring harness is taking forever. But I am going to leave the EVAP wiring out.