Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Mike Strober on February 09, 2023, 02:37:31 PM

Title: 1941 Cadillac
Post by: Mike Strober on February 09, 2023, 02:37:31 PM
I have a 1941 Cadillac and at 50 mph the motor shuts down. I have checked the fuel bowl but it is full when it shuts down. As soon as I let off the gas pedal the engine reignites. Any help with this technical issue is greatly appreciated.
Thank you-Mike Strober
Title: Re: 1941 Cadillac
Post by: wheikkila on February 09, 2023, 04:51:04 PM
Good Afternoon
Have you checked the fuel pressure? Along with how much fuel it pumps. Once you are sure about those items. I would check the exhaust next. If it is stopped up it will do the same thing. Let us know what you find on the fuel.
            Thanks Wayne 
Title: Re: 1941 Cadillac
Post by: LaSalle5019 on February 09, 2023, 06:19:25 PM
Very likely the fuel pump. It is hard to tell the difference in float bowl levels between running and not.

Questions:
Does hat vs cold engine affect this?

If you do a hard acceleration vs gentle does it affect what speed it dies at?
Title: Re: 1941 Cadillac
Post by: Bill Ingler #7799 on February 10, 2023, 12:15:18 PM
Check your fuel line for any crimps or bends that would cut the fuel delivery to the fuel pump. Also could be a blockage in the connection at your tank and the fuel line.
Title: Re: 1941 Cadillac
Post by: harvey b on February 10, 2023, 04:42:49 PM
Does it starve for fuel if you drive it hard,or does it quit when it hits 50.Try and run it in second gear and rev it higher to try and use up the fuel in the carb,if it doesnt stall i would start looking at your ignition system,a weak coil or condenser could attribute to this as well,Is the engine revving high when you are at 50 or is it sort of coasting?.Also check the timing and point gap too. harveyb
Title: Re: 1941 Cadillac
Post by: Ron Parker on February 13, 2023, 10:09:50 AM
You may want to run a compression test. A stuck intake valve can cause this. Ron Parker
Title: Re: 1941 Cadillac
Post by: toybox on February 13, 2023, 11:38:56 AM
More info is needed. When you say it dies , does it stumble or back fire and then die , or does it just stop like you turned it off?   Running out of fuel is normally like a hiccup or two and then dead where as if it just stops dead would indicate ignition problems.      Tim
Title: Re: 1941 Cadillac
Post by: Chopper1942 on February 22, 2023, 11:49:56 AM
I wouldn't worry about a valve sticking.  If a valve is sticking you would have a misfire issue.  An intake sticking open would cause backfiring in the intake manifold.  An exhaust valve sticking open would only cause a misfire. To check for a plugged or restricted exhaust, connect a pressure gauge that reads pressure and vacuum.  Hook the gauge to a manifold vacuum source. With the engine idling, snap the throttle to wide open.  The vacuum will drop to 0.  If it shows more than 1lb of pressure, you have some restriction.  If over 2lbs, you have a serious exhaust restriction. It really sounds like you are having a fuel delivery problem.  Check your fuel pressure at the carb fitting and then check the volume.  About pint in 30 seconds is good. Next reconnect the line to the carb and then disconnect the line from the fuel tank at the fuel pump.  Hook a vacuum gauge to the fuel pump inlet and start the engine.  You should see a high vacuum reading, usually 15-20 inHg.  If reading is low, you have a fuel pump problem.  The pump may be able to build pressure, but if the vacuum is low, it can't deliver enought fuel.