1995 k1500 NEED HELP ASAP

[Mpiper97321]

Hello... So my 350 crate motor swap has went perfect so far..... Everything went as planned and motor is in. The minute the battery is connected, all of the check engine lights come on. No key is in the ignition. I have check engine, battery, e brake, abs and possibly one other. Any ideas??? Truck will turn over and sounds fine but will not run. All the electrical connections are plugged back in. No electrical modifications were made. Just a simple long block swap. 350 for 350.

[TallCans]

Check your grounds, there's a bunch. I just did a crate swap last week. My gauges were being weird and I had a qdc that was loose and a couple grounds off

[Mpiper97321]

OK thank you. I had one small ground strap that I couldn't remember where it went. It was coming off the passenger side firewall. I've just never seen warning lights on like that and am ignorant to electrical. I'll give it a shot