93 4.0 overheat

[honey678]

I have a 93 4.0 that I swaped into an 83 CJ-7. It didn't pass the N/O (nox) smog part of the test- (I live in So Cal) it was double the max. All other test results were well below limits. It's running hot, but not overheating. New 195 thermostate from Jeep, new computer- replacement form Jeep, New cat. Cj rad W cj fan. No problems w rad before swap. New heater core. The Smog ref in Riverside said it didn't pass the nox test is because it's running to hot. The Idiot sweep gage displays far right side of the green on the freeway, & mid range driving around town. What to do?-Mike

[CanaMark]

I do not understand what the last sentence means. You should replace the O2 sensor on the exhaust pipes. As for overheating, you got everything replaced that I would have. Maybe before running the air test, let the jeep sit for a few hours before you get it tested. You need a shroud around the fan blades, it acts like a vaccumm, mine doesnt have one, but I hardly ever idle, but if I do idle I can idle for like a good 8 minutes before I start to overheat. You might want to consider installing an electric fan.

[myjeepsux420]

The temp of the engine is the direct result of the the failing emissions. You could also try to source a cooler plug? That might cool things off a bit. You could try to pass the test with the engine cold, but then you risk having high HC. Good luck! California emissions suck!!!