1988 Formula Firebird 305 TPI.

I’m suspecting that line from the gas tank to the evap canister is clogged. I’ve taken off vent valve and put a vacuum pump to the line to the tank. It’s holding vacuum indicating to me that it is clogged. Shouldn’t there free flowing air going from the tank to the canister?
I’m going to disconnect the line from the sending unit and see if it holds a vacuum there. Y

Car sat for 19 years.
Replaced tank, sending unit, pump
Having stalling issues, excessive pressure at tank, hard to fill.

 

You could disconnect that line under the vehicle at the transition from the in-tank unit to the body lines, With that frees, you could be more aggressive and use compressed air to try to clear the line without risk of inflating the tank or blowing other lines off.

 

Vader,
Thats what I did this morning. It was definitely clogged. I filled the tank. I was able to fill it at full blast.

It did not however fix the stalling issue. Still stalls at prolonged stops and sometimes putting it into gear. I’m just frustrated at this point.

I’ve replaced so much stuff.

MAF, iac, distributor, plugs wires, set tps. Hooked vacuum gauge up to brake booster hose, good vacuum.

Thanks for replying.
Dan

 

I've been down this path more times than I care to remember. This is likely an EVAP issue. Does it happen right away or after it's been running a while. Is it worse when it's hot?

 

i was able to blow out the line from the evap to the tank. Car sat for 19 years.

I adjusted the idle this time with the engine warm. Set the tps voltage to .54 volts. It hast stalled yet. It almost did when I left the car running to go inside and open garage door. That takes a few minutes. When I put the car in reverse it almost stalled but caught itself. I talked to a local mechanic that had a 92 Camaro. He told me after any adjustments to disconnect the battery both terminals and wait to reset the computer. All this did the trick. Start cold it goes to 1200 rpm then settles at 800