2017 Express S4 EFI--possible fried EFI system?

[nickdalzell1]

Customer just got a Express S4 EFI variant Ezgo (never knew EZGO made EFI???) and he claimed to have installed a radio, the radio worked, but he left it on and drained the battery.

He had attempted to 'boost' the battery with some ancient 1960s era 40 amp charger set to, well, 40 amps maximum. "I thought it'd get it off the trailer fast" he said. It did run, he got it off the trailer alright, then it stopped running after a loud pop he claimed was a backfire.

I was sent to evaluate it on a field service call. Got there, he had already put a new battery in it assuming the old one damaged. The radio does nothing (for a Kenwood, it looks very cheap) and the lights and turn signals work. There's a 'check engine' light under the seat that stays lit while cranking and with the key on, but I think it's just an oil warning light. I can't detect any burned wires, but it just cranks. no action from the fuel pump or ignition. no spark, no fuel.

Did he fry the injection system? Are the parts matched so you have to replace everything at once like an EX40? He said he had a warranty I suggested he go back to where he bought it from. I asked when he put the battery in if he got any 'big effing sparks' indicating problems, he said no. He assumed (incorrectly) that the radio not working was related to the cart not running. Since he did the radio DIY, I assumed the radio and/or use of that oversized charger overloaded something important. I can't find any sign of a computer or diagnostic OBD style port. I'm only familiar somewhat with EFI yamahas (which do have a computer/diagnostic) but never knew EZGO had an EFI anything.