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Honda Civic Si sudden valve knock

I have a 2003 Civic S1, 78,000 miles. While driving on the interstate the car started to hesitate and the check engine light came on. As I pulled off the engine stalled. I could not restart without a jump and when it did start I had a bad knock the sounded like a valve(s). The car will not run at idle speed, have to take it up to about 750 rpm or it will die. The battery is also dead. Oil fine, & temps normal. Belt looks good. Never had any noise before. Had not gone 20 miles before this happened. Any ideas. Could a voltage issue cause the car to get out of time?

It’s more likely you’ve slipped a cog on your timing belt. Don’t try to start it lest you lose more “cogs” on that belt and bend some valves. You may already have. THAT’S an expensive fix.

I believe the Si has a timing chain, and if that 's true valve timing is unlikely to be the problem.

I’d install a new battery and see what happens.

You didn’t say you heard any knocking before it stalled. The dead battery may have caused the hesitation and stalling.

After you get it running you should have the charging system tested. Trying to charge a dead battery is really hard on the alternator.

Yes, I am leaning towards electrical issue. The noise I hear could be clacking injectors due to low voltage. I confirmed that the Si does have a timing chain, these almost never go bad. I’m not running it until I can get it checked out. Do you know where I could easily check voltage output with my meter?

With the engine at a high idle and all accessories off the battery should have 13.8-14.5V.