My 2002 Pontiac Sunfire won't start, not even with a boost. Any idea? No electrical input at all.

TDC is after the number one piston comes up on the compression stroke. So if you take the valve cover off, you should be able to watch the intake valve and tell where the cam timing is as the piston comes up. Keep in mind if cam timing is off you won't have much if any compression on most cylinders.

have battery and alternator checked first

These vehicles are prone to failures in the antitheft system. This will actually lock out the starter and/or injectors. Read thru this link, might be your problem.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

When the car is cooled off bang on the exhaust. It's possible you have a heat shield that is loose. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Have you check the fuel pump

check alternator, not holding charge,also change belt and belt tenisoner.this may be causing battery to fail. I had same problem on my car.

check the fan relay, its either shorted or stuck, look in the fuse box under the hood for the relay,, it engages but won't reset, if you have 2 of the same relays,, switch them and see if the problem quits,, if so, Just replace the bad relay

This link should help you alot. These things are hard to diagnose and expensive to fix. They are rather cheap to bypass tho. http://vatspasslockpasskeysecurityhelp.yolasite.com/

i had aproblem with my 03 sunfire when the key starts to wear out it has a security problem in the ignition switch you might need a new key.

the crank position sensor is located to the back of the engine to the left of the oil filter, it is right next to the oil filter on the back side of the engine. hope this helps. Please rate my fix as i strive to be the best. need more help, get back to me Thanks Ray