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Running Rich, need OBD-ii live data advice

2K views 3 replies 4 participants last post by  ismaelyork 
#1 ·
98' XJ 4.0 AW4 with 155k on it. An on going issue for the last couple of years. Running rich to the nose yet occasionally throws a running lean code on bank 1. Now it runs rich to the point of spitting droplets of gas out the tail pipe and stalling at stops after it has warmed up. Goes down the freeway fine however.

I replaced the upstream O2 sensor a couple of weeks ago, with no noticeable difference. Looking for ideas on a fix. I have had a couple people guess a bad computer....

With Innova scan tool I get this info

Cold (initial start up)
upstream read .4 - .75
downstream reads .76

Engine at 192
upstream reads 0.00 - .88 (jumping quickly with nothing in between)
downstream reads 1.0 solid (way rich)

STFT remains -4.7 to 0 hot or cold
LTFT remains 6.0 hot or cold

A couple other odd things I noticed. Even when warmed up it remains in CL (closed loop). Shouldn't this have changed to open loop?

Also the TPS reads 15% even at idle. That doesn't make much since, but I have gotten that reading for a couple of years. Is this correct or another source of trouble?
 
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