Vannin' Home Forums Chevy General Discussion Van keeps losing all power randomly?

Anyone got any ideas? 78 g20 with stock 350. Runs great except that randomly, one of two things will happen. I'll come out to it and it won't start. Starter motor sounds fine. Has a new alternator and battery and belts. It just won't start. Then I'll come out to it 15 mins or an hour later and it'll start right up.

Then the really irritating one: when driving at low speeds, particularly when making tight low speed turns like a u turn, it will just cut off. Loss of power to the engine but not to the lights etc. Again, if I wait and keep trying to start it, it will start again just like normal. Sometimes 5 mins later, sometimes 20, sometimes 2 hours later.

The only thing I can figure is a loose wire somewhere. At some point someone put a security system in it which is not currently hooked up. Any ideas?

Battery cables & ground straps ...

In a points distributor, a bad condenser will cause a no start. I know GM had HEI long before 78. Not sure if there is one in there or not.

Check for spark when it's not starting.
Plus the basics, like frscke1 said.

I know on the later models, there is somd kind of funky failure in the column.
Good Wrenching Nomadgames!

I'll check. It doesn't lose power to the lights or dash or starter tho. Just to the engine.

There is a broken or corroded wire or connection somewhere .... it might look good outside but inside not so much. Start it up go under the hood & move some wires. Check the wiring at the starter.

It may be your fuse box ...

Get a multi meter start pokin around

Will do.

It could be your ing switch .... is the key on the column or dash ? The column has more chance of error than the dash type.

Get a spare coil. When it won't start, check for spark at the plug. if none, wiggle/retighten all wires associated with the coil. If still nothing, swap the coil. THe internal windings can do funny stuff.

Also check for corrosion any where there is a connector.

I’ve chased similar gremlins all over a vehicle only to figure out some moisture got into a group of connectors and corrosion gave it an intermittent problem. Clean the connections and apply dielectric grease.