Hesitation and sputtering when cold at low RPM's...ideas?

[jrhone]

This started a few weeks ago and is getting more and more prominent. So when cold and at low RPM's the car sputters and tries to stall...also hesitates bucks a bit then goes. When fully warm...everything seems fine and performance is actually very good. When cold, performance is good once it gets to 300 RPM or so...below that it hesitates, and sputters a bit. So to me it sounds like...it could be...

1. Needs tune up, cap/rotor/plugs. Car blows off carbon and buildup on plugs and other components after being run for a while.

2. Vacuum or intake leak. The car warms up and seals up the leak...

Its been about 9 months since a tune up, so its probably due. Its got Pertronix, no points. The fact that it runs great when warm would lead me to believe the carb is adjusted fine....and not to look there...also timing is ok...So other than those 2 areas...anything else to look at?

[Slackey]

Hello I just had a very similar problem. I solved it by replacing the condenser. Apparently there is something known as cold condenser where the metal laminations inside the condenser contract in the cold causing ignition problems.

See article attached.

http://books.google.co.uk/books?id=M9gDAAAAMBAJ&pg=PA182&lpg=PA182&dq=cold+condenser+oldsmobile&source=bl&ots=F6VaTZDtAu&sig=ILtbrB6jFhignGT1bhTzmHfShAA&hl=en&ei=Rn8fS7KDCYiu4QaQ_JD0Cg&sa=X&oi=book_result&ct=result&resnum=7&ved=0CCUQ6AEwBg#v=onepage&q=cold%20condenser%20oldsmobile&f=false

I know someone will pop in and tell you to never use a cigarette lighter under the bonnet but whatever. I warmed up my condenser one cold morning to test this theory and the problem was gone. Worth a shot i think. Cheers.

Sorry, just realized you have pertronix. Does that mean no condenser?

[c.d.iesel]

....carb anything BUT fine.

It's a choke and idle circuit thang

choke and Cold High Idle Step cam

must be working for cold start and Warm-up period.

with stone cold motor, choke closed, and High Idle

cam on it's highest step the motor should be reving at 1800 ,...2200

rpm after 10 ...15 seconds of running on it's own.

With a gentle tap on the gas pedal (if it's a water or electric choke)

the High Idle cam will drop to second step, and after 3 ,,, 5 minutes

the High Idle cam will drop to 'off' and now run on the base idle adjustment set screw. All this depends on condition of parts, cholke,

clean idle jets with proper sealing o-rings, correct HOT idle mixture

adjustment, correct valve adjustments, and have the ignition timing

"BALL" mark set in the window at 1400 rpm. every step

here must be met or your just pissing the motor off with maladjustments.

NOT cap, rotor, or plug wires. do throw in a set of new spark plugs

just because it's christmas.

p.s. - I love your camera 'rig' wish I had one on the sidecar!

instead of just a carboard throw-a-way kodak and duct-tape.

back to yer cold start / Warm-Up misfortune,

any gas motor needs additional enrichment for cold start,

and controled decreasing enrichment in a time frame that matches

the building motor temp - gradually leaning it out, leading up to fully

warmed and operation temp. that window is only 5 ...10 minutes of running time from first firing cold. (which is why we have evolved

to digital, fuel injection, with strict warm up, emission controled

motors today) you either have a Manual, Electric, or Water&Electric

choke - or - missing bent inoprative choke parts to play with here

you need to tell us what you have to proceed further.

and maybe unstrap the camera from the rig and point it at the carb

(both sides) so we can see what you have)

and read this from the great folks at PIERCE MANIFOLDS :

http://www.piercemanifolds.com/Carburetor_Set_Up_and_Lean_Best_Idle_Adjustment.htm

[fwardell]

c.d. is exactly right. My Weber 32/36 with manual choke had similar problems. Checked plugs, points, wiring, etc. - all fine. Timing was right on. Then noticed that manual choke cable had slipped in its bracket. Readjusted it, and all's well in the cold, infact, it's starts instantly when cold.

[jrhone]

THX guys, its a Weber 38/38 with electric choke.