my friend has a 95 z28 he said he was doing about 90 and let off the gas. well as soon as he did it back fired and blew a little bit of black smoke and the car died. now the car wont start im tring to help him to get it started any help where to start looking? thanks guys

 

Pull either number 8 or number 7 plug and put your finger over the plug hole to see if air shoots out when you crank it over. If so, look for spark on those plugs. If you also have spark, hook it back up and try squirting fuel directly in the intake and crank it over.

No air coming out of the plug hole would probably be from a disabled valve train which there could be several reasons.

No spark is probably from the rotor that is opti-frigin. No pun intended. Confirm by checking spark at the coil. More than likely you lost spark and this is probably why. The rotor either came off or shattered.

 

Blown rotor would be my first guess...

 

car has no spark at the coil

 

First thing to do is clean the coil real well and look for telltale white marks in the black insulator body usually near the laminations. Look also for cracks indicating it could be firing to the side of the laminations rather than from the terminal.

If ok, check the pink/black wire and also the white/black wire at the ICM for the presence of 12 volts with KOEO. Use the black wire going to the ICM as ground when checking the other 2 wires for 12 volts. If not there first check the #11 fuse (10amp) underhood fuse panel. If still not there let us know.

If good, check for the presence of the IC signal on the white wire going to the ICM. To do this, set the meter to AC and have someone crank it over while you check from the white wire to ground. The signal should be 1 to 4 volts AC, not DC.