VikingTrad3r

red = removed, plugged at tb.

yellow = connected, po did this.

in my quest to get this car running right id like to know if this would affect normal idle operation???

VikingTrad3r

here is plug at tb.








plugged at the tb. this is supposed to run down to the cannister.

Joe C

I hate when people start screwing around when they have no friggin idea what they're doing - . it's obvious from your diagram, the PO had no idea, and his mod doesn't even make sense. I love the screw in the tubing thing - . my suggestion - return everything to normal factory configuration. it looks like the previous owner tried to eliminate the canister from the system - not sure why unless it was throwing some code or something. not that it's correct, but it would make more sense to disconnect the vacuum line at the TB, and plug both ends. if returning to normal factory configuration, and it starts throwing a code, repair as needed. I don't know for sure, but I doubt it would have any impact on idle quality as long as there no vacuum leak at the TB.

one thing I would suggest is to replace all the vacuum and emission lines in that diagram. you have to remember those rubber lines are 30 years old. most of mine were deteriorated, dry rotted, and overall in pretty bad shape and in need of repair and/or replacement.

aklim

I'd remove the system completely but OP, you are already having problems, lets not do this till you are out of the woods. Poor GM manufacturing quality which is why mine fell off the car a long time ago. That's my story and I'm sticking to it.

All it does it take fuel tank fumes to be burnt up in the combustion chamber, IIRC. One more thing to leak, one more thing to fall off.

VikingTrad3r

wait a sec....idea brewing here....if the air that is supposed to supply the INlet to the cannister is METERED air through the MAF and then out the base of the tb into the T and over to the cannister......THEN if there is no metered air going into the cannister...but if the pvc vac line (which serves also as the cannister vac line) is still sucking ...when the purge solenoid opens...then that is unmetered air into the system. if the purge solenoid is stuck open, then it would be sucking air in there.

anybody know what the conditions are that make the purge solenoid at the cannister open?

Joe C

OK VT3, don't try to second guess or re-invent the wheel. first of all, there is no air supplied to the inlet of the canister, and is not metered thru the MAF. basically, the system is vacuum controlled. it operates under certain conditions, and takes fuel vapors from the tank and directs it to the intake manifold. the purge solenoid is ECM controlled, and only operates when the engine is up to temp, operating for a specific time, above a specified road speed, and above a set throttle position. here's info from the FSM - again, my suggestion, make sure everything is configured and operating to factory spec.

if you have a FSM, and you should, everything is covered under section 6E3-100, driveability and emissions - evaporative emission control system (EECS).

Joe C

question: is the purge valve electrically connected? the purge valve is normally open. if not connected, and with the PO's mod, manifold vacuum would constantly be pulling fuel vapors from the tank.

WVZR-1

A few weeks ago the OP had questions regarding the lines to the tank. This morning I was going to suggest removing everything that can't be "confirmed" as OE and start fresh. I believe that's the best move for the OP.

I believe the OP needs to remove the intake and reseal the top-side and start fresh. He's many questions (threads) that seem to HINT it would be in his best interest. A serious study of the FSM and an inventory of the components on the car and start so to speak fresh

Joe C

- everything seems to be a bit helter-skelter. I would definitely establish a good, solid mechanical base line, and consider a fresh OE start!

aklim

If it was introducing unmetered air into the system, you wouldn't get IAC counts of 30. You'd be getting 0 since the ECM has checked and it found that you have more air than needed so it is going to close off the metered air leak which is the IAC.