I bought this vehicle recently and have been experiencing a very high idle speed. I've read some threads concerning this topic and have a simple question to ask. How is the Carburator oriented in regards to the choke placement? In other words, is the electric choke located in the front, towards the fan or is it towards the firewall? I'd normally disassemble stuff to find out on my own but it's 3 below zero and I'd like to keep my troubleshooting time minimal. Thanks.

It's a 5 spd carburated 1989 B2200

 

the choke element is facing the firewall, if its that cold there the choke may be functioning properly, the idle should kick back down after the engine warms up. the choke operates a fast idle cam as well as the plate in the venturi which enrichens the fuel mix for a cold engine.
there is a wire from the choke element that connects to the back of the alternator. make sure that is plugged in and you should have voltage going to the
element when the engine is running.
you may need to remove (or lift up) the air cleaner assembly to inspect the element. becarefull not to break any vacuum lines.

 

thanks for the quick reply, the engine was idling high even after driving 25 miles to work so I suspect a problem. I did find the white coded vacuum hose had been removed and plugged with a screw, from the top of the air mixture solenoid so I replaced it. I don't know if that will cure the problem yet so I still might have to hot wire the choke to see if that is working.

 

It's been working ok most of the time since I last worked on it but it started to not idle down yesterday, on the way home. I again wiggled the wire behind the alternator but it still was idling high. At that point I removed the vacuum line to the top of the air mixture valve and then replaced it while the engine ran, it idled down upon reinstalling the vacuum line. So, I'm assuming that either I didn't have a good vacumm connection or that I have a leak somewhere. Does that seem like a reasonable assumption?

 

jeff its really hard to say whats reasonable or not. can you describe what you are calling the "mixture valve"
there is a vacuum line going to the choke pull off which slightly opens the choke plate when the engine is running.
your main concern is high idle correct?? have you verified that the choke element is actually recieving power from the
alternator while running?? using a test light would be fine.

 

the valve is called an air mixture valve in the vacuum hose diagram. it's over the passenger side wheel well and has a white and a yellow hose going to hose barbs projecting horizontally. the high idle speed has been intermittent but the weather here has been brutally cold which, I'm sure, doesn't help much.

 

ok, just checking.
is the air duct from the exhaust manifold to the air cleaner assy intact?? (this should have little effect on
choke operation, but it is needed to keep the carb from freezing)

another idea. ... remove the air cleaner lid and look into the carb, you will see the choke plate in the primary side of the carb (closest to
the firewall) is it really dirty?? if so, buy some carb cleaner spray and try to remove the gunk. start the engine periodicaly
so it doesnt flood with the cleaner. after everything is clean and dry, spray the pivots for the choke plate with WD-40 and also spray the linkage
on the firewall side of the carb. use a vacuum pump to make sure the diaphram for the choke pull-off isnt leaking, if it is replace it.

still dont know if the choke element is getting power from the alternator??