• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Cold Weather Driveability Issue

T

tx65coupe

New Member
I'm having a slight cold weather driveability issue. It runs fine when its close to 50 degrees out or warmer. When its down near 40 and close to freezing the engine kinda hesitates a bit under mild acceleration. If I accelerate more and the secondaries open up, the slight hesitation goes away or is skipped all together. This is with the car at operating temperature.

I was thinking that it was the electric choke not opening all the way. It appears that that is not the issue. Is it possible that the air from the fan moving across the choke is causing it to cool down and close slightly while driving?

Does anyone have any idea as to what might be causing this?
 
I'd re-tune the idle circuit, at that temperature. Or just open each idle adjustment screw 1/4 turn and see if it gets better. Or raise the float level. Your engine needs more fuel when its colder.

Robert

EDIT: That's assuming your ignition system if functioning properly.
 
I do understand that it needs a bit more fuel in colder climates. It may need an adjustment, but I'm not sure that is the issue though. It runs rich in warm or hot weather. I still think it runs a bit rich in cold temperatures too. The exhaust smells that way at least, even after its warmed up.
 
I should have mentioned this before. The carb is an Edelbrock 1806 with electric choke. The thermostat is a Motorcraft 190 degree. When the car is warmed up, it is operating at that temp.

It has an open element air cleaner with a Wix filter. There is no heat riser or anything like that.

Should the choke be fully open when the engine is at operating temperature in cold weather?
 
It turns out that the issue was the choke. At least it appears that way. I took the car out earlier tonight since the temperature was around 40 degrees. It was having the slight hesitation under moderate acceleration. I should have said moderate not mild in the earlier posts.

I stopped and removed the air cleaner. Well, the choke was open. I rigged it to stay open and continued with the test drive. The problem went away. So, somehow while I'm driving the choke was closing. I'm not sure if it was from cooling off too much or something else.

When I got home, I adjusted it and backed it off some. Then I went for another drive and it seems better, but I'm thinking it needs to be backed off a hair more.
 
Don't you understand that if you'd simply wait until the weather was sporting mid 70's temps that you would not have this problem?
:thu
 
"cmayna" said:
Don't you understand that if you'd simply wait until the weather was sporting mid 70's temps that you would not have this problem?
:thu
Click to expand...

:eek:mg
 
"tx65coupe" said:
It turns out that the issue was the choke. At least it appears that way. I took the car out earlier tonight since the temperature was around 40 degrees. It was having the slight hesitation under moderate acceleration. I should have said moderate not mild in the earlier posts.

I stopped and removed the air cleaner. Well, the choke was open. I rigged it to stay open and continued with the test drive. The problem went away. So, somehow while I'm driving the choke was closing. I'm not sure if it was from cooling off too much or something else.

When I got home, I adjusted it and backed it off some. Then I went for another drive and it seems better, but I'm thinking it needs to be backed off a hair more.
Click to expand...

Did you wait until the "engine temperature" was back to 40*. Like said before your fueling is relevant to the engine temperature. More fuel when the engine temp is 40 and much less when it reaches operating temperature. You also may want to check and make sure the timing is right and the advance is working.
 
You must log in or register to reply here.
Back
Top