Welcome to the Corvette Forums at the Corvette Action Center!

Engine stalling after warmup

eoseitz01

Active member
Joined
Feb 2, 2015
Messages
31
Location
Marysville
I'm currently building a new engine for my 74, but I'm wanting to figure out this issue before I swap engines in case it's not the old motor.

When I start up the car it runs fine. I can take it up the road a few miles no problem. However, once it warms up it wants to stall when you stop or turn. I have to use the hold gas and brake approach to get it back home.

Before I started my engine build I changed out the fuel filter, carb and rotary cap/button. It still does it. Could it be a bad vacuum advance? I'm using the distributor on my new engine so I hope it's not. I also noticed a hissing sound coming from the brake booster area when I shut it off. I changed out the hoses and the check valves. I also changed the check valve on the valve cover because it looked old and crumbly.

Any ideas?


Sent from my iPhone using Tapatalk
 
the hissing will be a vacuum leak. Below the brake booster will be an Evap cannister. Check this and the hoses to it for leaks.
If a vacuum leak is large enough it can cause issues with your idle.
 
Pinch off or disconnect and plug the vaccuum line to your brake booster and see if the problem goes away, if it does you need a new brake booster. You should not hear any loud (very audible) hissing with the engine off. Good luck with it. :)
 
Well the evap canister doesn't appear to be connected. The hose to the fuel line is there. I plugged it back in, but the carb line is nowhere to be found. Which port on the carb does this go to? I have two on the front. One is plugged and the other goes to the vacuum advance. I'm guessing it can't be leaking if it's not there.

I replaced the hoses, check valve and grommet to the booster. I still hear a hiss when I shut the car off.

I can pump up the breaks with the car off. When I start the car, hold the break and shut it off, the pedal comes up after about 5 seconds. I'm thinking it should be 30 or more. Sounds like it's probably my booster.

On a side note, when I was checking my break booster I noticed the mount under it is about half rusted. Is this a body mount or part of my frame? What issues will this cause?


Sent from my iPhone using Tapatalk
 
Engine runs much better after plugging booster. Shifts normal again too. Will a break booster off any other vehicle fit or is it corvette specific?


Sent from my iPhone using Tapatalk
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Back
Top Bottom