1993 rx7 FD LS SWAPPED cranks no start
 

Car drove just fine, would sometimes die if I let it idle at a stop sign. But only like once every few days. Now the Car cranks but won’t fire up

checked fuel rail, has good pressure. Don’t think it’s a fuel issue.

checked spark plug and a coil with a light tester and didn’t get spark.

All fuses are good according to my multimeter. Any ideas as too where to start? Where should I start testing for ground or power?

No spark can be a sensor problem, harness problem, problem with the power to the ignition coils, or possibly an ECU problem. Nothing about that would be RX7-specific, and with an engine swap you're probably better off running through the troubleshooting section of the shop manual for the year/make/model that matches the engine harness and ECU. Good luck, I drove an LS swapped FD once and it was a lot of fun.

Update: found that the injectors aren’t receiving signals either with a noid light test.

any ideas?

does this occur on both banks?

Here's a granny's link regarding wiring an LS1 into a 3rd gen

https://grannys.tripod.com/3LS18.html

I'd check for 12V on the respective pins of C100 and C101

Update;

swapped can shaft sensor, has to take off fuel rail and intake to do it. After putting everything back, I’m not getting my fuel pump to prime to get fuel pressure anymore. Still have original issue. Any ideas?

If not getting either spark or fuel, need to start working backwards toward the ECU. Do you know how the ECU receives power? There are endless ways the LS ECU and accessories could have been wired in.

I would start here: Starter Cut Relay Bybass and once bypassed, check power into the ECU with key on.

Start drawing a diagram of how the ls is wired in.