The weather around here has been getting really cold in the mornings and of course a new problem has come up. I have a chokeless holley 650 w/ mechanical secondaries sitting on a GM 330hp crate motor. In the mornings when i fire it up it idles fine, right at 600. I normally let it sit for 5 min to warm up in the driveway but lately its been dieing after about 3 min. the idle just seems to fall off until it is too low to run anymore. If you just barely put your foot on the gas you can bring the Rpms back up to 600 and it idles fine, as long as you don't let off. This morning i set the idle up when it started to dive but in the afternoon when the weather is a little warmer the idle's at 800 (too high for me). Any suggestions?

You simply need to install a choke... mechanical or electric. That's what the chokes job is...
That's why the factory installed one... When the choke and fast idle circuit are set up properly the engine (when cold) will run a little faster at idle until it warms up and then returns to normal idle. http://www.chevelles.com/forum/smile.gif

I'd sugest an electric (Holley) choke.

------------------
FastSS396Man
Brian

Fastss396 (http://chevelles.com/showroom/fastss396manflqtr3.jpg), Fastss396 (http://chevelles.com/showroom/fastss396manflqtr2.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manrrqtr3.jpg),
Fastss396 (http://chevelles.com/showroom/fastss396manint1.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manint2.jpg),Fastss396 (http://chevelles.com/showroom/fastss396mantrunk2.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manfrchassis.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manexh.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manengine1.jpg),Fastss396 (http://chevelles.com/showroom/fastss396manrchas1.jpg)
69' SS396 Chevelle
L78 396/375hp
M-21 Close Ratio
Cortez Silver
10 year Resto
It's brand new again!
02' Harley FatBoy, Diamond Ice pearl.

I forgot to mention, the problem does not go away when the motor reaches operating temps. It seem to be directly related to the outside temp. I can be driving around in the afternoon and it seems to run fine but when evening/dark rolls around it starts to do this again. I can't be running with a choke on everytime the temperature drops below 45 degrees.

You probably have what is known as carb icing. Without a choke and the manifold air heater the comes with closed air cleaners and if you don't have a heat riser in the right hand exhaust pipe, I don't see any way to get rid of your problem.

------------------
Leo Paugh
Maryland Chevelle Club #017
A.C.E.S.#3731
progress has little to do with speed, but lots to do with direction.
Maryland Chevelle Club (http://www.clark.net/pub/chevelle/mcc.htm)

How cold does it get there?
How warm does it get there?
What is your operating temp?
What temp is your thermostat?

If you're in a snowy region, or the temp doesn't get much higher than 60 or so at it's peak, you might wanna try a higher temp thermostat.

Lately the highs have been in the 50-55 range.
Lows in the mid 20's-30's.
Operating temp is at 165 with a 195 thermostat.
No snow here (Cali)

I think your opperating temp is too low. With a 195* thermostat your op temp should be 185* to 200*.

You may be haveing more than 1 problem. A cold start problem and warm up should be fixed with a choke. As mentioned earlier.

You could disconnect the choke in the summer if you wish when it's not needed.

Engines need enough heat at op temp for the rings to seal up properly in the cylinders and for all other adjustment to come into specs.

You should also check for vacume leaks. This could be causing variable changes in RPMs. This could also affect higher RPM performance too.

I don't know? Just some ideas.

Brian
SSMan

[This message has been edited by fastss396man (edited 01-26-2002).]