https://www.nicoclub.com/archives/us...-database.html
Comprehensive FSM database.
IAT on the SOHC cars is separate and in the airbox. It does cause a CEL if the delta between it and the coolant temp sensor is too high but ECCS doesn't use it on the SOHC for fuel trims, so that's coincidental with your issue.
If you're curious about the IAT sensor here's more info;
https://www.youtube.com/watch?v=m6EhtMGRivA
Another vid of a rough SOHC. Have you checked your distributor timing? When you disconnect the MAF it throws the ECCS into limp mode, changing your fuel trims and timing both into open loop.
I'd start there. If you verify your dizzy is installed right at TDC, then get it running w/ MAF unplugged and check timing w/ a timing light, I'd go into checking the wiring harness. The first pic I uploaded from the FSM gives you wire colors. Disconnect the battery and the ECU and verify continuity between the ECU connector side and the MAF plug. I had a broken CAS wire once that would cause my SOHC to just randomly die when it went over a bump/pothole. I'd get no spark or fuel then tow it home only for it to run like nothing ever happened. Biggest PITA to diagnose ever. So basically you're going to have a multimeter set on resistance (ohms) and to verify continuity you want a low value when you connect each lead to both ends of the wire. NEVER TAKE A RESISTANCE READING ON A LIVE CIRCUIT.
I'm guessing it's your timing though.
*edit* Also, you need to adjust that TPS! you can't just slap it on. it has to be aligned or the engine doesn't know what the actual throttle position is.
https://240sx.org/faq/articles/throt...or_adjustm.htm
Yeah it's written for a DOHC but it works for the SOHC as well.
It's frustrating when people get half way through troubleshooting their car and decide to start a new thread on it. You lost all of your info from the old thread, stuff you did etc...
