It stays in closed loop for about 5 seconds, sounds like it is stumbling and goes to open loop. Runs ok in Open loop for 20 seconds, then repeats. I'd be find running in OPEN loop but I think my mileage would suffer. Can it run without the knock sensor?

 

You don't need a knock sensor.

But, a bad knock sensor will never cause driveability problems since it generates it's own signal if there's knock. No signal and the eCU could care less.

Your O2 is too slow. Got 12V to the heater portion of it?

 

I might be talking out of my butt with this, but I recall another thread about higher flow injectors stating that an ECU reset was necessary to let it learn how to adjust to the higher flow injectors.

Something like disconnecting that positive battery cable and grounding it to the chassis to discharge caps then putting it back on the batt...then doing something like on/off cycling of the ignition and turning the headlights on in between. Like some kind of cheat code on a Nintendo or something...

 

https://www.cherokeeforum.com/f2/jee...ocedure-46047/

 

Yeah. Butt is speaking loud and clear. LOL.

That's for later than Renix.....

 

Knock Sensor-This is logical. The scan tool does show basically 0 knocks at idle and under 20 when revved up so I guess it is working.


Disconnected O2 sensor and reconnected after cleaning contacts. No more cycling but it won't go into CLSD loop no matter what. I had it on the highway for 10 minutes, it would show DECEL but never closed. Ran pretty well but I could see it was only adjusting the pulse width on the injectors and not doing anything with the ST or LT fuel trim. The trims stayed static.


The O2 voltage is displayed. When idling it was as high as 4.2 volts on cold engine. It was around 1.02 volts when I pulled back in my driveway with a warm engine. Exhaust still read "LEAN"-I never saw that change to RICH.


I'm going to leave it for now and see what it drives like tomorrow. It's puzzling though.

 

Good try but the Renix doesn't store any codes

 

Long crank times are more of a Cps issue then o2 or knock. Shoot my jeep runs fine without an o2 hooked up, but I wanted better mileage so I put one in it...not going into closed sounds like the coolant temp may be getting groggy, but that's more of a guess. Also the odd idle, double check the tps engine side, and your map

 

Eliminated the C101 on my neighbor's 87 and his lazy O2 sensor got some mojo and worked great. Hmmmm.

 

Yeah-I know, I should do that. I did disconnect it, clean it and prod and poke the connectors.


I'm wondering if the O2 heater relay might be acting up and turning the heat off and on which screws up the O2 ready. It's a puzzler.

 

I thought that also.

Quit being a weenie and eliminate the C101. Solder and shrink tubing.

Plus, you can get rid of those crappy ground connectors as in Tip 6 all at the same time.

 

I did this. It's not hard at all. Just take your time and do one wire at a time and you'll be fine.

 

Thanks for the help-It's like a blizzard here now (we get the same weather as Buffalo) but the C101 elimination is on my list. My garage is too packed to work in side right now so I usually work on the Jeep in the driveway just out side of the garage door. I'm hoping this snow goes away by mid-week


I know-I'm a weenie!

 

Just an update: Replaced O2 Sensor with Delphi unit. Cycling problem gone. Goes into closed loop very quickly now. I'm sure my mileage will be better too. Replaced cap and rotor after just for fun but I did the O2 first to make sure that was the problem.


Now the O2 readings are rapidly changing on the scan tool and the RICH/LEAN is switching a lot. It was almost locked on LEAN before.


Thanks for the advice.

 

As expected.