the engine shut off mid cruise ???


The Grumpy Grease Monkey mechanical engineer.
Staff member
quote....Nice cool day in AZ and I took my car out for a short drive. Never had a problem before, but today the engine shut off mid cruise. It almost felt like it was out of gas, but it wasn't. It would crank, but wouldn't fire so I was stranded on the side of the road for about 5 min. Finally, it started again and I took it easy driving the 1-2 miles back home.

When I got home I gunned/raced the engine and it died again. I checked the jets in the carb to make sure it was getting gas and it is. It cranks normally, but wouldn't start for about 5-10 minutes again. Then it started and ran perfectly. I gunned it up to 5,000rpm and its working perfectly. Starts up like nothing ever happened.

Does anyone have any ideas what could be going on?
My first thought was fuel, but fuel is coming through jets in carb. HEI ignition, that is working perfectly. It was running great and just cut off. Started after 5 minutes and now starts great every time. Will take it out again tomorrow, but so far I can't repeat the weird engine shut off. It's a 63 impala SS convertible. Mildly built 383, HEI, mechanical fuel pump, all new parts.

obviously you'll need to isolate the cause , of the engine cutting off,
to a flaw or failure in the ignition or fuel delivery issues first

Id check fuel level in carb, and fuel pressure fluxuations,
as I think that's a bit more likely than ignition issues from what you describe
as it sounds a bit like the carbs either flooding or running low on fuel,
maybe due to sticking needle fuel valve or defective fuel bowl floats
but be aware ignition modules in HEI distributors , and ignition coils, do fail,
lack of the correct thermal grease under the ignition

Arctic Silver 5 High-Density Polysynthetic Silver Thermal Compound AS5-12G - OEM


also fail
and can act like that intermittently:swearing: be damn sure you use the correct thermal heat transfer grease,
under any new ignition module you replace let-Ne...

or fuel pressure variation issues high/ low at times, a fuel pressure gauge on the dash ,
connected to the carb inlet port, that you can watch,


and a fuel pressure regulator with return line, thats easy to adjust is likely to help

related info threads

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Rick said, HEI modules are notorious for quitting when hot once they have some miles on them. It's common for them to cause the engine to shut off when hot. Let it cool and it will usually start. Repeat that cycle and it won't run as long the second time and will take longer to start again.
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I use dielectric grease for that very reason when installing modules .