When my car heats up it slowly starts to cut off why?

Question

i have a 89 caprice that i pulled the factory 305 out of and replaced it with a 350 with a 600 4150 holley. ive checked all fuel lines,filters,regulator,pressure,floats,... idle mixture,spark plugs,pcv,any idea why this could be going on?

Answer 1

HI

What kind of shape is the 350 in?

A high mileage motor well run OK cold and as the oil warms up and thins out they start running bad at tolerances get lose. Try a bigger radiator.

Good Luck

Tim

Answer 2

what do you mean cut off?....do you have a catalytic converter? if so disconnect it and see if this issue goes away....is the choke on the carb set correctly?

Answer 3

I've seen that happen when the exhaust passage in the manifold that passes under the carb to heat up the mixture when it's cold, gets clogged with carbon. Or somebody put some tin foil in those 2 passeges to keep the air cold. Could be.

Answer 4

DID YOU MESS WITH THE FLOAT LEVEL? IF YOU DID NOT , THEY MAY BE STICKING . IT WILL IDLE WELL THEN UNDER A LOAD, IT WILL CUT OUT DUE TO A LACK OF OR, OVER FUELING. THE 1850 SERIES 600 CFM CARD IS A GOOD ONE. IF YOU HAVE THE "SMOG VERSION" OF THE 600 CARB, I SUGGEST YOU HAVE IT TUNED TO THE CAR. THAT IS-- IF YOU DONT KNOW HOW TO DO IT YOURSELF.  IF YOU DO NOT KNOW HOW, DONT TRY ! YOU'LL ONLY MAKE IT WORSE. CHECK THE ELECTRIC CHOKE TOO . MAKE SURE ITS NOT HANGING UP OR STICKING . TRY RUNNING IF FOR A FEW MINUTES WITH THE CAR CLEANER OFF AND SEE IF THE CHOKE BUTTERFLY IS OPENING AND CLOSING PROPERLY. YOUR CAR ALSO HAS A COMPTER AND IF YOU HAVE A BAD O2 SENSOR IT COULD SENDING A BAD SIGNAL TO THE ECU.  GOOD LUCK WITH IT