Help with 96 GTX died under WOT, started and died again

[artr]

I was debugging a no spark problem and changed the CDI to a spare I tested this spring and it started up. The battery was low from a lot of cranking trying to debug the no spark problem. Took it for a test ride and was running WOT and it was like the key was pulled from the post. I thought it might have moved because the lake was rough. Pulled the key, put it on, 2 beeps, started, idled a few seconds then died again. Only clicks when trying to start after that. Also said 12V low. Recharged battery, tested ok on load tester, put VOM on battery and watched voltage drop to about 8V when start pressed and solenoid clicked. Just tried removing plugs and turning flywheel by hand. Feels locked. What can cause this situation other than a seized engine. Can the starter fail and lock up the engine? What other things should be tried? Thanks.

 

[JeremyD615]

First, pull the pump and verify that the problem is on the engine side... You might get lucky and have a locked up pump rather than a seized engine.

 

[POPPS]

What do your plugs look, (if you have aluminum on a plug, then unfortunately you have a failed engine., top end).. Even with normal looking plugs, you can have a bottom end failure...(usually brass rotary valve gear). It is rare, but you could have a failing dess post.

 

[artr]

Plugs were normal. Removed jet pump just now and luckily it was locked. Can turn flywheel now. Thank you both JeremyD615 and POPPS for your quick response and helpful suggestions.