TheFerret55 Posted May 14 Share Posted May 14 Hey everyone, I’ve been trying to figure out what’s keeping my 1988 MJ stuck in open loop but I haven’t been able to find the reason. On my REM after it warms up it’ll show that the voltage is moving (when it’s cold it stays at 4.98v) but I keep getting an error code for O2 heater voltage low. I checked the orange wire at the connector with it running and it showed 13 volts, also I put in 2 brand new sensors to see if they’re the issue. On NickInTime’s website it says that it could be caused by the ECU being stuck in WOT mode, how can I check to see if that’s the case? Also here’s a video showing the numbers and the code. Link to comment Share on other sites More sharing options...
Ωhm Posted May 14 Share Posted May 14 What's your ST & LT Fuel Trim values? Looks like your running LEAN. Check your manifold bolts. Link to comment Share on other sites More sharing options...
TheFerret55 Posted May 15 Author Share Posted May 15 5 hours ago, Ωhm said: What's your ST & LT Fuel Trim values? Looks like your running LEAN. Check your manifold bolts. Yeah it’s given me a lean code as well. I’ll check the manifold bolts and see if they’re loose. It also has all new vacuum hoses so it’s all set there. If the manifold bolts are loose would that contribute to the O2 heater issue? Link to comment Share on other sites More sharing options...
TheFerret55 Posted May 15 Author Share Posted May 15 Just checked the manifold bolts and they’re all tight. I’ll get it running tomorrow and take a look at the fuel trims. If my manifold bolts are tight and there aren’t any vacuum leaks then what could be causing a lean condition? Link to comment Share on other sites More sharing options...
fiatslug87 Posted May 15 Share Posted May 15 What’s the Ω reading between A and B on the O2 sensor? Should be 5-7Ω. Link to comment Share on other sites More sharing options...
TheFerret55 Posted May 15 Author Share Posted May 15 25 minutes ago, fiatslug87 said: What’s the Ω reading between A and B on the O2 sensor? Should be 5-7Ω. When I checked the sensors they were both in that range Link to comment Share on other sites More sharing options...
cruiser54 Posted May 15 Share Posted May 15 Have you completed Tips 1 through 5 at www.cruiser54.com yet? Link to comment Share on other sites More sharing options...
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