ok...what do I do with the two lines that went to the TBI on the duke...I have a 3800sc from a buick Riviera. I did the search function but he has the evap system I don't... you know the two hard lines on the trunk wall? can I just put a u tube from one to the other lol?
I just finished my 3800 and would like to know this info too since it is starting to warm up outside. From what I gathered one needs to go to vacuum. Don't know other than that.
I read you can delete the canister and put on a vented gas cap too
If you do pretty much any engine swap and wish to retain the Fiero's EVAP system and keep it functioning, you'll probably need to install the EVAP purge solenoid that came with the donor engine that you're swapping into your Fiero. On the stock Fiero engine, the throttle body had a ported vacuum signal that controlled the Fiero's charcoal canister's purge function, mechanically. Newer engines usually lack these ported vacuum sources, so you will need to wire in an EVAP purge solenoid to control this function. The purge function is needed so the charcoal canister can be purged of stored gasoline vapors so it does not become saturated (which will quickly occur if it is not regularly purged). As the fuel heats (by daytime warming or by the engine running and the fuel circulating thru the fuel rails), the fuel vaporizes in the tank and this excess vapor must be dealt with - otherwise it would just leak out to the atmosphere causing a raw gas smell or could even create a dangerous situation if the car is stored in a sealed garage. Below is a vacuum diagram of how to hook up a computer-controlled EVAP purge solenoid to the existing Fiero charcoal canister.
-ryan
------------------ OVERKILL IS UNDERRATED Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com
ohhh I see so just tee together and put on evap solenoid and run line to the little thingy that has one big nipple and two little nipples ? so no electrical connections? I still got the egr stuff I removed from the 3800SC just cant remember what it looks like
Yes, there will still be an electrical connection - to the EVAP purge solenoid you'll need to install.
Even though I disabled the EVAP related codes in your custom PCM tune I made for you, the EVAP purge solenoid will still function if you wire it up to the PCM.
So what do most guys do ? Do they bother hooking up a canister ? I've looked at many pics but don't see any canisters.
I don't know what most guys do. I can tell you that every swap I do in-house leaves here with a charcoal canister and functioning EVAP purge solenoid if it is required.
The job of the charcoal canister is to store raw gasoline vapors generated by fuel heating (which is normal operation while the car is running and fuel is circulated thru a hot fuel rail on the engine). Heating the fuel causes it to vaporize and expand in the tank, so you have to vent the tank so excessive pressure cannot build. Without a charcoal canister, these vapors would have to be vented to atmosphere, which can create an annoying raw gas smell or a potentially dangerous condition if the car is parked in an enclosed garage.
The charcoal canister can only store a certain small volume of gas vapors and it must be purged periodically. Stock Fiero engines used a ported vacuum source on the throttle body to open a valve on the canister to purge it at part throttle operation. Modern engines no longer have ported throttle body vacuum sources so a computer-controlled EVAP purge solenoid will need to be used to take over this function.
You should not run a canister without having some means of purging it and you should not plumb constant vacuum to the canister to continuously purge it (as this can cause engine running problems). So, the rule of thumb is if you are going to do a 3800 swap into a Fiero, add the EVAP purge solenoid to the stock Fiero charcoal canister as I showed above and everything will work properly.
Thanks Darth Fiero. Is the purge solenoid only vacuum controlled or is it electrically assisted ? If electronic where do you connect the wires ? Should a new canister be purchased or is there a canister that you recommend along where to place in the engine bay with the 3800SC ? Thanks for your time.
Any 3800 SC from 92 on has a purge control function in the PCM. The wiring for the control should be in harness. The power feed can come off the same circuit as the charger bypass solenoid. The purge control solenoid should have been mounted between the intake and one of the valve covers on the donor engine on series II. If not someone through it away. On Series 1, could have been mounted on the canister. It is simpler to use the controlled set up rather than all vacuum. The PCM is expecting it. You will need to have the vent function and tank pressure monitor functions edited out of your PCM programming, but leave the purge function on. I had mind set up just like the diagram shown earlier with the stock Fiero canister and had no problems with it. If you are careful, you can pop the top off the cap of the vacuum control on the Fiero canister. You then can remove the plunger from the rubber diaphram under the cap. Replace the cap with the diaphram to seal the cap and plug off the top vacuum port. This will allow the canister to vent with only having to have 1 larger vacuum hose. You can use a vacuum single port canister, but most are too big for the Fiero bracket. The solenoid will be controlling the vacuum so you won't need the plunger under the diaphram to be opened by vacuum. Make sure the vacuum source is full vacuum, not boosted pressure. On top right next to the throttle body where you would also connect brake vacuum. If unsure, go to a pick and pull and find a Series II SC and look at the vacuum lines. Snag the solenoid and hoses if you are missing yours.
[This message has been edited by cmechmann (edited 03-26-2015).]
Thanks Darth Fiero. Is the purge solenoid only vacuum controlled or is it electrically assisted ? If electronic where do you connect the wires ? Should a new canister be purchased or is there a canister that you recommend along where to place in the engine bay with the 3800SC ? Thanks for your time.
You can reuse the stock Fiero charcoal canister with an engine swap, assuming it is in good working condition.
The purge solenoid is electrically controlled by the ECM/PCM; but yes, it also has vacuum lines going to it (see the vacuum diagram I posted earlier). The purge solenoid will need key-on 12v + power on one wire and the other wire gets connected directly to the ECM/PCM.
You can relocate the Fiero's charcoal canister if it is in your way for what you are doing in your swap. I commonly move them to the hidden area just ahead of the right rear tire (meaning the inner wheel liner for that tire has to be removed to access the charcoal canister). Relocating the canister means you'll need to reroute the fuel tank vent line to its new location, as well with rerouting the vacuum line that leads to the EVAP solenoid and then on to the engine. You can mount the EVAP purge solenoid near the charcoal canister wherever you put it, but keep in mind it does rattle during operation so you might want to mount it to a rubber strip to isolate it from the chassis so you can't hear it from inside the car.
[This message has been edited by Darth Fiero (edited 03-27-2015).]
Darth, you wouldn't happen to have any pics of a relocated canister would you? I plan to move mine on my stock 2.8 while the tank is out, I just think it's an eye sore. Thanks!
I might as well start doing this too i think I still have my evap canister and purge valve I just have had it venting to atmosphere the past 10 years. Sometimes I get a gas smell but what is more prevalent is the exhaust smell without a cat.
This picture shows the two pipes coming off the canister joined together:
Then the pipe goes to the 3800 purge solenoid: (Which is disconected at the moment beacause it makes too much noise in operation! But in this post, Darth Fiero suggests fitting it on a rubber mount; may well try that!)
Then the pipe goes to the appropriate inlet on the 3800 throttle body: The thing I indicated on this photo is a Toyota Supra PCV valve. It's necessary as my motor is turbo. The Supra PCV valve is often used in these kind of applications because it can take boost without leaking past.
Hope this helps.
------------------ "Turbo Slug" - '87 Fiero GT. 3800 turbo. - The fastest Fiero in France! @turboslugfiero https://youtu.be/hUzOAeyWLfM
