Cold choke misfit...

[Peer81]

Hello everyone, here i'm again with another problem.
I have this vette almost 2 years and want to solve the little annoying things.

Here is one.
When a start my vette (cold) the rpm goes to 1200 (normal choke rpm was around 900 i thought..) I don't touch the gaspedal and just let the engine spin around idle. After around 2.. 3 minutes the rpm raises itself to 1500.. 1600! I still do nothing, then after around 5 minutes (total of 8 minutes) the rpm raises again to 2200! The rpm will stay at a regular 2200 till a press the gaspedal and then it drop's instantly to 550 rpm and stay's there.
Well i know it's a choke problem because it only happends when the engine is cold. But the choke on a 81 is Computer Controlled..
Anybody any idea how to solve this problem?

Greetings Peter.

 

[MoeJr]

Hi Idle cold should be between 1800-220 rpm. The gradual upswing you describe could be a weak choke pull off or too lean a choke setting. Also believe 81 has a tps as part of the carb. This is another piece to look at. Car should idle around 750 rpm in park fully warm and 600 in drive. I never liked having my carb cars idling so low in drive. My 77 Pontiac Grand Prix is set to idle at 700 in drive. Just my .02

 

[DDLS3]

Peter,

Your 81 has an electric choke, not computer controlled. 12 volts are applied to a bi-metal helix which heats up and opens the choke plate, which then allows the throttle to be kicked down. What you have described is GM specification almost exactly, in other words it is pretty much working like it is supposed to. If you want your choke to kick off a little quicker you will need to rotate the black choke cover a notch or 2 toward the lean side. If your choke is original then the cover is riveted and likely won't move. You can drill out the rivets with a 1/8" drill bit and replace the rivets with small sheet metal type screws if you want to adjust it. If you want to lower the high idle, the high idle adjustment is located on the choke rod latch mechenism on the right side of the carb.

 

[Peer81]

Oke, so my choke is oke after all. I found it a little bit weird to see the engine to into 2200 rpm without touching the gaspedal. Personaly it's no problem for my, but i just hate thing that aren't correct on my vette. But this is the easiest way to solve a problem Thankx for the answers!

Greetings Peter.