Electrical problem

[Cshenker1121]

I have a LS3 with a GM performance ecm and harness.

This things been driven quite a bit and was turbocharged but we recently took all of the turbo stuff off, and when I was hooking the battery back up (red top optima) getting ready to pull it out of the shop, I hooked up the cables backwards and it threw sparks,I quickly disconnected them and I put them back in the right place and it started up.



This new problem I’m about to explain didn’t happen until I got it back from a shop. When I turn the key and hold it, the starter cranks then acts like it loses power, then cranks again and starts right up. Any suggestions on where to start looking?

[nokones]

How much compression are you running? My first guess it may be kicking back on you. Put a volt gauge on the battery and when cranking see what the voltage drops are. If it is not dropping below 10.5 volts than it may be kicking back on you unless the starter is having issues.

[Wayneburns]

How much compression are you running? My first guess it may be kicking back on you. Put a volt gauge on the battery and when cranking see what the voltage drops are. If it is not dropping below 10.5 volts than it may be kicking back on you unless the starter is having issues.

If it’s not the battery it should be from the kick