idling issue (bring on the flaming)

[McGyver]

well i have seen it posted here before and i know it has been covered but for the life of me i can not find it after about 15 searches. sorry

i have a 95 sierra with the stock 1.3 and stock carb and at the moment have a problem with it idling at around 2000 to 2500rpm, now i think i remember something being said about vacum hose leaks or carby leaks etc but im just not 100% sure. if anyone can point me in the right direction that would be great.

[lay80n]

Check your auto choke isnt staying on. Otherwise check for vacuum leaks.


Layto....

[McGyver]

this might be a stupid question but how do you check for vacum leaks i watched a mate do it this one time with a spray bottle of what im guessing a highly flammable liquid, and he sprayed around untill it started reving higher. is that what you mean?

[Fatz2326]

and how do you check your auto choke
Thanks

[PCRman]

this might be a stupid question but how do you check for vacum leaks i watched a mate do it this one time with a spray bottle of what im guessing a highly flammable liquid, and he sprayed around untill it started reving higher. is that what you mean?

CRC clean-R-carb works well as it tends not to flood the area so you can pin point your leak easier. But you have to be confidant that it is a gasket or manifold leak rather than a lose vac hose or similar.

[lay80n]

Check your vacum hoses to see if they have come off, or are cracked/loose. You can spray the manifold flange and carby section with carby cleaner and see if the idle changes. Personally i woud check the auto choke, as your description matches that. Then take the intake hat off the carby and check the choke plate to see if its open at normal opperating temp. It should be eitehr open or close to it. Also check if the two coolant hoses entering the carby top are teh same temperature, if they are not you have a blockage somewhere. If you want you can back off the choke adjustment screw when the car is up to temp and see if it changes. If it is the auto chock you can either just disconnect it, or clean it out.

Layto....

[Fatz2326]

Lay mate,
Can you point me to where the auto choke is and/or how to disconnect it:P

[Jacked]

in the yellow pages under automotive - repairers

[Adsport]

lol.


there will be some wiring going to a round box on the side of the carby, thats the auto choke. inside there is a heater element that uncoils as it expands while voltage passes through it when your ignition is turned on. this in turn rotates the rod that the choke plate is fixed to.

[Eff]

this might be a stupid question but how do you check for vacum leaks i watched a mate do it this one time with a spray bottle of what im guessing a highly flammable liquid, and he sprayed around untill it started reving higher. is that what you mean?

The real McGyver would be able to fix it with 2 pieces of string

Eff

[McGyver]

the problem is my pocket knife is blunt and i have not had time to drop in to the hardware to get some duct tape. thanks for all the help everyone sounds like the choke because i only have the problem once the car has been running for a while.

[sheps]

the best thing i did to my crappy carby was to pull heaps of
bits off and when the motor stopped i put that bit back on.
runs like a dream. even though i removed every thing to do with the choke and cold idle i have no problems starting it when cold.
i call it a simplified sierra carby and it works for me.