Can you remove the Evaportive Emission Control system on a 78?

[78ZCARBLUE]

Can you remove the evaporative emission system with no adverse effects on the engine?:bulb: Thanks in advance for your help:)

[sblake01]

What's the reason you'd want to remove it? In states that require emissions inspections, you'd run into problems there. In reading the description of the system in the FSM, clogged lines and/or removing the system could lead to things like gas fumes and/or insufficient delivery of fuel to the engine or vapor lock to name a few. If it's working, I'd leave it alone.

[78ZCARBLUE]

Some of the lines were damaged in a wreck so I was looking at removing the entire system instead of restoring the damaged lines. Also my state does not rquire emission inspections. Thanks

[sblake01]

I'd fix it. It ties in with the fuel vapor venting system and the EFI is 'calibrated' to run with it hooked up and functioning properly. These cars run bad when the carbon cannister is clogged or has a dirty filter. It would take a bit of re-engineering to remove the entire system and everything else work the way it should. JMO.

[TomoHawk]

I had mine off for a while, and I don't think the fuel tank or expansion tank like it much. You get a LOT of pressure on the fuel tank, and it pings a lot from the pressure..

Stephen,

Is there any more information about why the engine won't work well with the cannister off, or why it's 'calibrated'?

thxZ

[sblake01]

Well, that's why I put the word in brackets. It's not really callibrated per se but it's designed to run with the evap system intact. By that I mean that the mixture, the fuel pulse, etc. are all set through the various sensors to work with the fuel vapor that is drawn into the intake from the cannister purge line. The more throttle you give it, the more vapor is drawn in. Since it designed to work that way, I don't know what you'd do to compensate for that function if it wasn't there.

[TomoHawk]

From the diagrams, the purge line goes directly to the intake, and the purge valve tees off the vacuum line to the distributor (or into the BCDD.) The former is unmetered air, and the latter isn't. Perhaps it works out to be "balanced" in some way. Otherwise, the AFM or (AFM bypass) should probably be adjusted, but we won't mention that here, because that's 'secret voodoo' stuff... More research needed probably.

txZ

[sblake01]

Yeah, I've done some experimenting with that myself. I have a exhaust analyzer so I'm not afraid to mess with the AFM adjustments. A couple of years ago, I did some tinkering and actually got the car to run half way decent without the evap hooked up but the fuel/expansion tank pressure you mentioned was actually kind of scary, the fuel economy decreased, and no way would it pass smog. I came to the conlcusion that I should just hook it all back up and set the AFM back to how it was. I've not researched it any further.

[78ZCARBLUE]

I will go ahead and repair the Evaportive Emission Control System plumbing and hook it back up. That why I like this site so much! you can always get sound advise from the members, Thanks so Much!!