TheFerret55

When I checked the sensors they were both in that range

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?

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?

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.

Drove it on the highway this morning and it seems to have a little more pep to it with the new ecu and the cold starts are smoother

I looked over the case and couldn’t find any other part numbers besides the one sticker on it. Maybe I could find it if I took the case apart? It was a struggle to get it installed so I don’t really want to take it out again for a while haha

I installed it last night and I could noticeably tell it was idling better. Haven’t been able to actually drive it yet since I had some other stuff torn apart but I’ll report back today once I drive it.

Would you happen to know the performance ECU part #?

I just pulled an ECU out of a 90 Cherokee (doing the upgrade for my 88 MJ) and noticed it doesn’t have the factory sticker on it but one that says it’s a Mopar rebuild from 2002. Is there anything special with these (I heard somewhere that there was a Mopar upgraded ECU at one point?) or is it the same specs as an OEM computer? Thanks!