well my motor took a crap last weekend, heres what happened. i was racing an evo, and as soon as i put it in to 4th it back fired real loud then died. when i turn it over it doesnt eved fire at all. i checked spark and fuel, and there both there. i pulled a couple plugs and they look like they were running lean. my fuel system should support what i have done, and my tune is from mad z28 so it should run prety rich since its a base tune.

heres what i think it could be
bad opti but there is spark at the plugs

hole in the piston, when it turns over it seems to turn unevenly like theres no comp in a cylinder

brocken ring. i think it should atleast try to start if that was the case.

im gonna do a compression test as soon as i get my hands on a tester. if anyone has had this problem, or has an idea please let me know

 

It sound like it will probably be broken piston rings but another possibility is something off in the timing, chain off by a couple teeth due to broken gear, no way to know till you at least do a compression check, good luck with it and I hope its nothing major. If you can though do a timing light check while cranking it to see how your timing looks. To check your fuel are you checking for preassure or checking for pulse at the injectors? a good possibility is low preassure or bad pulse to give you that backfire.

 

If it has spark and fuel, it is lacking compression. I would look for bent pushrods or maybe it jumped a tooth on the chain causing valves to stay open. Start with the comp. test...Good luck