Piston Slap: Stalling Stude’ requires second opinion?
I have a ’63 Studebaker Avanti which will start up, run for five seconds, and then shut down. I have changed filter and use gas preservative. Car will continue to start up and shut down, many times. Fuel pump is working (has an electric as well as a mechanical pump). Any thoughts? My mechanic has replaced the condenser several times recently, not sure why; would this do that? Or is the float not opening up the needle valve? Thanks for any suggestions.
Great question! By any chance do you have a fuel-pressure gauge on the fuel line, or one that you can connect to monitor the pressure as the motor stalls out? We need something like this to 100 percent rule-out a weak/failing fuel pump (or pumps). Or perhaps there is too much fuel pressure and the carburetor is flooding itself … but odds are that would be very noticeable.
Anyway, once the fuel pressure is confirmed to be within spec (usually 5 to 10 psi), we can consider an issue with ignition. Tell me what you think.
I am not a car mechanic, so don’t really have ability to do that. However, it seems to me that the chances of two fuel pumps failing at the same time would be like winning the Powerball. I can hear the electric one. I don’t think it is flooding out, no strong gas smell.
Perhaps my initial request to check for fuel pressure isn’t necessary, but that’s usually where I start. Voltage drop(s) can take both pumps out, but maybe the stalling Studebaker needs another opinion.
You can take apart the carb, give it a good clean, or a full rebuild. Or, don’t touch the carb yet and check for vacuum leaks (via smoke testing) or check the resistance of parts of the ignition system. Odds are it isn’t a vacuum leak, because it runs for a few seconds. The ignition could be an issue, especially if it’s been upgraded with non-standard parts that are either used (i.e., worn out when removed from the junkyard) or of poor aftermarket quality.
But, again, ruling out fuel pressure makes it easier to determine if whether you’re facing a fuel, spark or vacuum leak. And a drop in fuel pressure really feels like the first place to look.
What say you, Hagerty Community? Is fuel pressure the first thing you’d look for?
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