DoubleV

What could make a CCC car suddenly run so bad it will often stall, about 2-3 minutes after a ( very ) cold start? If the throttle is blipped while running rough ( or you restart it because it stalled ), the problem just goes away and dosn't return untill the next cold start.

There are no codes, the carb is rebuilt, and everything else SEEMS to be just fine.

Totally at a loss here.

P.S. During this 2-3 minute period of running fine, I'm not doing a thing ( not even reving it ). It's just sitting there warming up then BAM, it runs like crap.

DoubleV

So have I stumped the collective knowledge of these forums or what?

Aldakoopa

I dunno. My car runs like crap consistently. XD

naf

iTrader: (7)

My '85 would do something similar occasionally when cold started. Idle fine at high idle for a few seconds (certainly less than a minute) then slowly die off. On restart it would run fine with no other symptoms. It was an occasional annoyance and curiousity but I never got the urge to look into it because of my dislike for cold weather.

Since the motor swap to a 350 it hasn't displayed this symptom. I can tell you it was not caused by the AIR system (removed because of broken/corroded tubes), the EFE (gone too) or the air cleaner (replaced with an open element). My first GUESS would be to look at the charcoal system. Disconnect it and see if it reoccurs.

Air_Adam

Is the choke set properly? Is it opening all the way? How fast is it opening? What is the fast idle and normal idle set to?

DoubleV

Yes.

It does once it's warmed up, but this problem is occuring well before it's warmed up. It's happening about 2-3 minutes after a cold start. Car's still in open loop.

Haven't actually timed it, but it's opening at the same rate every other carb I've seen opens at.

Don't remember exact settings but they are set at appropriate levels.

To recap, I pump the gas a couple times, start car ( it's on fast idle and idles fine ), I put it in R and back out of the garage, I put it in P, open hood ( already have air cleaner removed ), stare at engine purring like a kitten for 2-3 minutes, out of nowhere engine starts sputtering and often dies.

If I get to the car in time to give it a quick rev before it stalls, it magically goes back to idleing fine and the problem doesn't return.

If the car stalls, I restart it and everythings fine.

Naf, I'm not running the vapor cannister.

GXR11

did ya have the issue before the rebuilt carb went on?

DoubleV

No but this problem didn't start until recently and well after the rebuild. Carb is definatly rebuilt correctly. New AC Delco MC solenoid, good TPS, rich/lean stops to spec, float to spec, no leaks, no throttle shaft play, etc. Carb is a very nice low milage one too.

Yeah, it could use some tweaking for smoother idle ( once it's warmed up in closed loop....it's fine when in open loop ), but that should have nothing to do with a sudden stalling out of no where ( which fixes itself with a quick rev or restart ).

Could it be a glitch in the ECM ( unlikely but...). Float sticking and the car running out of fuel ( blipping throttle un sticks it )? These are just wild shots in the dark because I can't think of anything else that would cause such behavior.

Damon

Is it cold out where you are? Do you run an open element air cleaner or is the hot air Thermac system defeated on your stock air cleaner?

If so, it could be carb icing. It's where the throttle plates get cold (from the fuel atomizing/evaporating as it passes them- and evaporation is a cooling process, remember) and cause the moisture in the air to condense and freeze around them, choking off airflow and stalling the engine. It takes a few minutes of running for enough moisture to condense and freeze on the throttle plates before the problem pops up. And if you run it long enough to get everything under the hood fully warmed up the ice will again melt and the problem will go away. There's a "middle time" from maybe a couple minutes to 10-15 minutes where it can be a problem and cause stalling when you come down to idle.

The good news is it does no permanent damage and is a "self-fixing" problem when the weather warms up.

DoubleV

Yes it is usually very cold when I start the car and I usually have the air cleaner removed ( and hood up ) when doing so since I always end up removing it anyway to tinker.

Perhaps I will keep the original air cleaner/setup on and see if that helps.

Thanks for your suggestion. I never really thought about carb icing since I've never experienced it before. Hopefully that ends up being the issue. I'll know for sure when the weather warms up.

Air_Adam

What intake do you have? Does it have an exhaust crossover?

DoubleV

I'm just running a stock aluminum intake and no the crossover isn't blocked off but I did remove the vac line going to the EFE valve during the summer ( with no change from what I could tell ). I did this to see if I noticed any difference without it since I'm gonna be going with headers in the future.

mjk1210

what kind of cookie?

DoubleV

You chose that for your very first post? Yikes.

Besides, no cookies will be distriputed until the problem is properly diagnoised. I will not be able to tinker with my car for a couple weeks.

mjk1210

Thanks for noticing.

casperlord

What kind of carb is it?

If its one of the rebuilt Rochester Quadrojets, ive had a few winter problems with a few different ones.

I had the problem that you described quite well and it turned out my choke would not open and close right. A bread tie to keep them open constantly, and the problem went away. I got another 5000 miles before I got sick of that carb...

You might want to check the choke and make sure its opening and closing right.

rodsatheart

iTrader: (1)

Chance are that when you first start the car the choke butterfly is 100% closed and after a short time it starts to load up and will die out especially if you put it under load by putting it in gear to back out. When you pop the throttle or start it back up the butterfly has opened up a bit allowing the air fuel mixture to lean out a bit.
Quick fix is to adjust the choke so the butterfly is open just a bit. Might have to experiment with it some to find out where the engine wants it.