Hello, I've got a 2000 Express with a gasoline V8 which has sat for 3 weeks, and it is showing alarming symptoms when I try to start it.

When I crank it, it chugs a few times and then begins to make something like a "clank" or "clunk" noise. At the same time as the clunk, the motor stutters and the dash lights dim. The noise is evidently coming from the engine, and it visibly lurches in the engine bay.

Here is a video: https://drive.google.com/file/d/1Ezl...w912fZ_0J/view

Does anyone have any idea what could be causing this? Thanks for the time.

 

I would try turning the engine over by hand, using a breaker bar on the crankshaft, and see if you can feel anything. You could also try taking out the spark plugs and peeking into the cylinders if you can see anything. You could also watch the starter motor as you crank and see if there's anything weird happening there.

 

What should I be looking/feeling for?

Are you thinking of hydrostatic lock or water in the cylinders as a possibility?

 

I don't know. That's why I would be looking for clues.

 

whatever it is i would stop trying to start it till you take the plugs out and stop holding the starting on for so long.

 

It sounds like a bad starter solenoid. Engaging and then not then clunking back in as you continually crank it. The clunk coincides with the pulleys moving and then not.

The fact that it does not fire could be many things.
I had a 2002 and when the spark plugs were very old the increased gap caused a weak spark and very hard cold starting. Also the points under the dizzy cap get corroded and impede spark.

Try cleaning the cap and rotor, and check your plug gaps.....Close them up a bit if needed, then try again.

I also had an issue with my ignition key, and yours may be not making clean contact when trying to crank....

 

sounds expensive

 

Thanks everyone for the advice. Ignition was the issue - I pulled the distributor and found corroded contacts, and the spark plugs measured wide. I replaced cap, rotor, plugs, and fuel filter, it started easily and runs well now. I'm relieved it was a simple fix.