87 305 TPI, manual tranny

Ok, I posted on here about my charcoal canister leaking fuel,
https://www.thirdgen.org/techbb2/sho...hreadid=310294
Here is what I did to it so far. But now I'm having another problem and I thought they might be related so I'm making another post.

1. I adjusted the IACV and the TPS by the tech articles and it is idleing at around 750rpm now, which is alot better than 2500rpm.

2. I don't think its the canister that is giving me a problem, I took the fuel line running from the tank to the canister off and it is just pouring with fuel. From what I understand about this system is that it is supposed to just pull fumes off the top of the tank, correct? Why would I be pulling fuel? Is there supposed to be some kind of restricter in the fuel line between the tank and canister only allowing vapor that i might be missing? I checked the fuel pressure at the rail and it was spot on 40psi. So I plugged the line with a bolt and am bypassing the canister at the moment. And from what my uncle says, he has a 87 Buick GN, I can eleminate the canister altogether.

3. My new problem, I'm not getting any codes, but my car now runs like crap, like maybe I was missing, but when It idled high it was running pretty good. And also the tach was smooth, now it bumps up and down. Could bypassing the canister cause this? Any other ideas?

Thanks guys.

P.S. When I removed my gas cap it made a hissing sound, is that normal? Am I over pressurizing the tank, I thought my gas cap was a vented one and it wouldn't do that.

All these things sound interrelated, but I'm no where close to sure about this, and I'm sorry if I'm asking about to much at once. Just can't figure it out on my own.

 

If the fuel tank is over filled, heat and expansion can slug the EVAP canister with liquid fuel. Had any heat lately?

 

OH YEA, its in the high 90's here this past week.

 

Hissing from the cap is normal when you take it off. It IS vented, but it's designed to hold about 1 PSI of pressure before it vents nasty polluting hydrocarbos into the atmosphere. ABove that point it will vent, preventing damage to the gas tank, etc. This has nothing to do with overfilling, however. In short, it's normal, as long as you have the correct gas cap on there.

It's unlikely that the canister would be causing the "tach jumping" you describe. If you see the tach wiggling there's something electrical going on- something shorting, arcing, etc. The the pickup/module inside the distributor could be going south. Bad pickups and a jumpy tach are a common pairing.

 

I got to reading over the steps to adjust the IACV and TPS and I think I got ahead of myself and didn't disconnect the distributor wire on the firewall. I'm thinking this is why it is running like crap. What do I need to do now? Set the timing? I've read that stock is 6* and then I can advance it from there until I'm happy with it. Is that correct?

Thanks

 

What you're talking about relates to setting the ignition timing. That's a first step BEFORE you do the IAC and TPS, so yes, it can be important if your timing was pretty far off while you set the IAC and TPS.

Disconnect the "timing wire" that sticks out of the wiring harness above the heater box. Single wire, in-line, weatherpack connector and the wire is tan with a black stripe, if memory serves. Disconnect it, start the motor, set your timing to 6* BTDC (stock), shut off the motor, reconnect the wire and start the motor again to confirm no persistent check engine light. Then do another round through the IAC and TPS settings same as before.