I have a 91 Cherokee 4.0L and I decided to upgrade my injectors. I got what I thought at the time was a good deal on 6 refurbished injectors with the 4 hole orifice (part number FOTE 5, 280150943). Afterwards my jeep ran too lean and would backfire through the air cleaner. Sometimes the check engine light would come on and after paying for a diagnostics check, the technician told me that all sensors were in specifications. He told me something must be wrong with my injectors because it was running too lean and the computer was trying to compensate by asking for more fuel. Well, I found my old injectors, put new o-rings on them (with a little motor oil) and reinstalled them on my engine.

Now my Cherokee runs great again! So my question is why did this happen? I read here on the forum that many have made the conversion with no problems. I am still interested in increasing my fuel economy with today's gas prices but not at the expense of a poor running vehicle.

Also what about the Performance Chips that lay claim to increased fuel economy?

Precept

 

Did you reset the computers?

 

Also looks like you got the wrong injectors according to the numbers you gave. Search this forum for injector swap. There is a lot of great info. That's how I learned to swap some neon injectors in mine!!!

 

How do I reset the computer?

 

Disconnect positive battery terminal and hold it to the ground terminal for 30 seconds. Reconnect turn key to "on" but don't start it. Turn lights on then off, turn key off then back on and start! It worked for me. Will run a lil rich at first but the computer will adjust it within the first 50 warm up cycles.

 

Thanks for all the help. I found the threads regarding injectors and numbers. I have them copied so the next time I am in the wrecking yard I can go on an injector hunt.
Precept