In open loop all the time, causing it to run rich and crappy, some times it hits open loop and screams?

Tiny
GAGETGONEWRONG
  • MEMBER
  • 1992 NISSAN 240SX
  • 4 CYL
  • 2WD
  • MANUAL
Hello. I heard your guys are the best. Im in a conundrum, I have a 1992 240sx nissan. At first the car ran to cold I believe in open loop all the time, causing it to run rich and crappy, some times it hits open loop and screams. I do have a huge radiator with dual 10 inch fans. Today all of a sudden the car just doesnt start, I couldnt get it to start with the injectors connected, I unplugged them and it started and ran for a few seconds, burning off the flooded gas, I switched my ecu's from the automatic trans one to a manual one, then I unplugged the gas pump relay and I could get the car to run with my foot on the gas. I know the car is for sure flooding. The injectors must be dumping fuel. I pulled plugs and there are puddles of gas in the cylinders. My oil smells of gas too. This JUST started happening. My modifications, egr delete, intake manifold gut out with butterfly holes welded shut, aftermarket header, cold air intake, and full 2.5 inch exhaust. Rebuilt ka24de engine, with 185 compression all the way across. Any help would be appreciated. ANd I cant stress this enough when the car actually ran, like I said it ran cold, then the second it went from open to closed loop it just raises HELL!
Monday, June 20th, 2011 AT 1:24 AM

1 Reply

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
More than likely we have a temperature sensor issue. Is your temperature gauge working properly?

Either way we need to find out if the temperature sensor is giving the proper info to the engine control module.

Basically, if it is staying in an open loop then the module is not seeing that the engine is reaching the proper operating temperature.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

However, if the temperature sensor is okay, then we need to replace the ECU as this is going to be causing the engine to continue to run in loop.

I attached the info below on this system which shows how it reduces fuel as the engine warms up.

Please run through this info and let me know what questions you have.

Thanks
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Saturday, December 18th, 2021 AT 8:45 AM

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