WONT FAST IDLE WHEN COLD

[jaco963]

hey everyone, Im new to this forum, but i just got a new stock carb and everything is working fin except it wont fast idle when closed the choke closes when its cold and i have adjusted everything it says to in the pdf manual except the automatic electric thermostat for the choke.. any ideas would be greatly appreciated:)

[Petros]

there is a fast idle adjustment on the bell crank next to the throttle cable. The normal idle screw is a larger screw that uses a flat screwdriver next to the carb housing, the cold fast idle is on the throttle shaft and is a much smaller flat screw (it will move with the throttle plate, the normal idle screw does not).

Scrfew that one in, it should cold fast idle at about 1500 rpm. If it makes no difference when you screw in the fast idle screw than there is something wrong with the linkage on the choke or the choke itself does not close when cold.

[jaco963]

yeah i have done the procedure of adjusting it the rite way in the pdf manual so ill check out the linkages on the body rite now. thank you for the reply

[jaco963]

so all the linkages look rite and its about 85 degrees outside the choke is about half way closed i dont think thats rite?

[Petros]

choke has nothing to do with outside air temp, but rather engine operating temp. IT should be fully closed when cold (you have to open and close the throttle to reset the choke when cold), and opens as the engine warms up, and fully open after about 7-10 min of running. IT should fast idle when cold at about 150O rpm, and than drop down in steps as it warms up. Warm idle should be about 800 rpm, I have to idle a bit higher since I have a highly modified engine.

You might also check on vacuum leaks, sometimes it will make the car idle improperly if there is a vacuum leak, these cars area prone to vac leaks because of all the vac lines. inspect all the lines, and if you find nothing use carb cleaner while it is running and spray it on all the intake and carb gaskets, vac lines and vac operated equipment. It will slow the engine down when you spray it at the location of a vacuum leak.

Good luck.

[jaco963]

ok so in the manual it says, to set the fast idle shut off egr system by removing the hose from port m on the tvsv then plug it, then slightly hold the throttle open the close the choke completely then let go of the throttle and it should hold the choke closed. Dont touch the throttle after that....did all that and it was idling at 1100 it says it should be 3000 so i set it...shut it off tapped the throttle, to reset the choke and still nothing it wasnt to hot and i did let the engine cool, I even tried it this morning at about 50 degrees? still cant figure it out:/

[jaco963]

ok i got it finally it fast idles and breaks the fast idle when it gets warm! A vac leak-_-

[dlb]

congrats!

[Petros]

A vac leak-_-

Hah! always suspect a vac leak when it does not behave the way it should. All those hoses and vac operated parts gives lots of opportunities to cause a leak.