Hey guys,so the 350 in my cutlass is constantly dieing at low speeds or while at idle at a stop light.This is a california car originally with emissions stuff that i have now mostly removed and caped off. My questions is,is there some vacumm line or something that would keep the engine from cutting off at low speeds? at the moment it feels like im driving a stick,comming to a stop i have to put it in neutral,keep the engine reving above 1500k and so on.any help would be great.

 

Try removing the vacuum line to the brake booster and capping it off and see what that does. Mine was leaking like a sieve and my 455 didn't like it too much so I can only imagine how a 350 would react.
If that doesn't do it then check the timing. Other than that start looking for large vacuum leaks.

 

coil?

 

Would pluging off the booster affect my brakes?also if I cap it off do I need to cap off the booster and engine ends or just the engine?

 

Yeah, plugging off the booster WILL without ANY DOUBT AFFECT YOUR BRAKES, so don’t being doing 90 down the street. You probably will be required to use both feet to stop the vehicle.

Do you have a vacuum gauge? The easiest way to figure-out if you have a vacuum leak is by attaching the gauge to a vacuum port and watch if the needle swings randomly while idling. What is the measured vacuum at idle? Compression test is another cheap test you can perform to determine the condition of the engine. Just: 1) Pull all the plugs before testing. 2) Crank the same number of times on each cylinder and keep the throttle wide open while cranking.

I just rebuild my truck's engine. It also stalled out when I applied the brakes. Each cylinder’s compression was great and great vacuum pull too; but it idled very rough. It turned out that the problem was resolved when I pulled the Carb, torn it down, cleaned it, and reassembled it.

A lot of that CA smog crap actually helps idling, people yake-it for extra ponies. You didn’t state what yr olds your is.

Brake boosters are expensive and I've not seen one fail (yet).

 

Randy was only talking about checking to see if the booster is bad, not driving with out it. So to clear up things remove vacuum line to booster plug it up. Start car, if it is running smooth then the booster was the problem. If it is still running bad then its not the problem. Then hook it back up.

I have had three booster fail over the years.

 

He got it.

 

Hey, sorry to sound like a noob but I am. Its ironic to come on here today to ask the same question. My 70 Cutlass S with a 350 is doing the same thing and stalling out whenever i stop or slow down, getting the car started is a problem, i have to put it in nuetral and gas it to get it going. I did not play with any of the emission equipment on mine, if it even has any. What are some more possiblities that can cause this. I am going to check the timing tomarrow but what are the other possible issues. I thank you for your help in advance!

David

 

Fuel filter needing to be replaced.

Needing a tune up: plugs, plug wires, cap, and rotor.

Vacuum leak: intake gasket, carb. base gasket, bad vacuum line, or booster bad

Timing or air-fuel mix, just a few things it could be.

 

Everyone is a noob at one time or the other! Check the choke. An incorrectly set up choke can make starting almost impossible. Make sure you pump the gas pedal once or twice when the cars cold so that it properly closes the choke. If it is too far open (too much air when cold) it won't start. If it is too far closed ( not enough air) it will flood the engine and it will be hard to start. In either case you would have to gun it so the engine will overcome the lack/over abundance of air/fuel mixture. As for the roughness and stalling at lower engine RPM, make sure your idle speeds are correct using the recommended speeds and adjustment sequences.

 

Thanks for some of the pointers! I appreciate the help!

David

 

I took my 1970 out for its second maiden voyage tonight. I drove about 7 miles and when I slowed down to pull into a gas station, the engine stalled. I too had to keep the idle higher to avoid it from stalling whenever I slowed down or stopped at a red light on the way back home. Frustrating thing about mine is EVERYTHING is new (booster, carb, HEI, all hoses, etc.) and the engine was completely redone and buttoned up nicely.