Hi - I have a 1979 CJ7 with a Howell EFI on an AMC360. I added the Howell about 15 years ago and it has been great. Well, it ran open loop for at least a year before I figured out that it needed better grounding. I’m not the best with electronics but I go to extremes to avoid taking my junk to be repaired by someone else.

I joined last night because it is running like garbage since the fall. Rough idle, stalls if I don’t give it gas, and runs waaaay rich. Unsure what I did to cause this, but it started after I made a bunch of changes last summer/fall building some tube fenders. I accidentally clipped the tach feed wire and after about a couple of weeks of troubleshooting, found the wire issue but now it is undrivable due to mystery issue.

Last weekend I replaced the MAP sensor. No difference. I also connected to TunerPro. I don’t yet understand how to use it well, but it showed some interesting issues:
- it showed much higher rpms than my tach. About 50% higher. Tach believed to be accurate.
- volts showed at about 10 vs. voltmeter gauge and multimeter both read just over 12
- runs closed loop but crazy rich

To anyone that made it through all of that, thanks and please send suggestions on next steps. Until then, I am going to absorb what I can on troubleshooting this system.