ENGINE RUNS BETTER WITH THE CHOKE PARTLY CLOSED?

grumpyvette

grumpyvette

Administrator
Staff member
the (choke) is used to temporarily richen the f/a ratio, making the engine easier to start on cold conditions, restricting the flow rates , with the choke, typically increases the vacuum signal the venturies see and richens the effective f/a mixture ratio, as it tends to draw more fuel. if your running better with the choke partly closed richening the jets usually tends to solve that. BUT ITS ALMOST 100% INDICATOR YOUR CARB NEEDS A RICHER A/F RATIO
now obviously the type of jetting and the float settings, adding differant boosters, discharge nozzels,fuel pressure levels, accellerator pump settings,the type of carb, engine size, cam timing or other factors might come into this in some applications



http://www.2carpros.com/how_does_it_work/choke.htm
"Carburetor Choke Operation
A choke is used in conjunction with a carburetor. It is a valve that opens and closes and used to restrict air flow. The restriction enriches the fuel/air mixture to aid in the initial startup of the vehicle. The choke creates a stronger vacuum to pull more fuel from the jets and into the air/fuel mixture. When the engine warms up the choke slowly releases and stays in the wide open position."


choke_closed.jpg



http://www.carcraft.com/techarticles/116_0508_carburetor_showdown/index.html

116_0508_boost05_z.jpg

IVE ("wasted" A ton OF CASH GAINING A GREAT DEAL OF EXPERIANCE)
I guess I would not know 1/100th of what I know without having done that though!:rofl:
 
drop back to the basics
any trouble codes?
is the battery fully charged?
does getting a battery jump help"
any blown fuses?
do you have spark at the plugs?
do you have good fuel pressure"
is there water in the fuel?
what do the plugs look like?
OLD POST

"throwing parts at a problem is wasted money, if you don,t ..know whats wrong,
.................. lets start with the basics, use your head, some questions won,t apply to YOUR problem

whats the COMPRESSION TEST reading for each cylinder?

HOW did you adjust the valves?

is there water or crud in the gas or fuel filter?

CAN you post detailed pictures of EACH spark plug?

whats your FUEL PRESSURE?(does it stay steady as the rpms build?)

HAVE you verified the throttle blades in the carb and linkage fully open?

how are the carb FLOATS SET?

what air filter SIZE and is it clean?

whats the TOTAL IGNITION ADVANCE?

whats the VACUUM READ AT IDLE?

whats the VOLTAGE at the COIL?

AT WHAT rpm does the advance reach MAX advance?

WHAT is the exhaust back pressure reading? (IDLE and 4000rpm under load)

HOW did you determine true TDC or did you just assume the timing tab and damper are correct?

What color is the ignition spark?

what is YOUR OHMS reading on the plug wires?

whats your spark plug gap?

CARB JETS? METERING RODS?

HAVE you REPLACED the cap and ROTOR?

ANY indication of a MISS or BOG?

HAVE you tried a DIFFERANT CARB?

have YOU verified EACH cylinder is firing?

have you VERIFIED the FIRING ORDER IS CORRECT?

HAVE you VERIFIED the LASH/PRELOAD on the rockers RECENTLY, and are you sure the cam is not worn?

are you SURE the trans fluid and rear differential are filled to the correct levels?

whats the engine temp after it warms up?

whats the trans fluid temp?

"

read

http://members.shaw.ca/corvette86/Component Location View 86.pdf

http://www.digitalcorvettes.com/forums/showthread.php?t=54543

http://www.digitalcorvettes.com/forums/showthread.php?t=54543

buy

http://www.obd2.com/scantool/scantool.htm

http://www.amazon.com/gp/explorer/B0002KKIAK/2/ref=pd_lpo_ase/102-7445206-4788911?

or (depends on year)

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=46030


YOU REALLY NEED THIS


KNOWING WHAT YOUR DOING IS IMPORTANT, TO GETTING GOOD RESULTS!
no one knows everything about all models and years so it helps to have the correct procedures and info in a handy referace source,now you can get by with a HAYNES or CHILTONS manual, or something similar, but for detailed info, OWNING the CHEVY SHOP MANUAL FOR YOUR SPECIFIC CAR IS ALMOST MANDATORY!
I get asked frequently, "how did you know how to do that?"
well, EXPERIANCE plays a big roll, working on similar cars and engines helps, and the INTERNET is a good resource... but theres ALWAYS a big need for DETAILED REFERANCE MATERIAL, SPECIFICALLY MATCHING YOUR PARTICULAR CAR and if you have not yet invested in a SHOP MANUAL for the year make and model of you pride and joy muscle car your either not serious about your hobby, or most likely NOT A SERIOUS HOT RODDER! I constantly see guys SCREWING up installations, or adjustments,if you don,t know exactly what your doing, you need to either let the dealer do it and PRAY his mechanics are experianced and can read, OR..if your like ME, you would rather do it yourself and KNOW its been done correctly...
if your not aware, heres where to order them....

1-800-782-4356

http://helminc.com/helm/homepage.asp?r=

your average shop manual may cost $100-$150 ONCE! but youll easily save far more than that in reduced time and screw ups in under a years time or in many cases on one job vs having the dealer do the work!
 
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