After my coversion, Suby's been running a rough and I have very little lowend torque. She's now better after I got the CEL turned off (Purge, EGR and NSS), but she's running rough, I feel small surges throughout the RPM range, and she's running about 20 deg hotter than she did with the Weber. Sounds to me like a running lean condition.

I disconnected the O2 sensor just to see if it might be bad, and CEL did not turn on! She was fully warmed up so, I would think she would be in closed loop mode. This don't make sence to me.

Other possibility is the coolant temp sensor is shot, I do have another one laying around that I'll try. It's state is unknown, I'll hafta see what happends.

Any thoughts?

 

Well, off to replaceing a t-stat in another Suby...............................................

i've run multiple XT6's without O2 sensors and the CEL light does not come on and the car drives very well. gas mileage will dip some, but otherwise they run well without it. i don't see an issue here.

 

if you suspect the water temp sensor (and it can cause an issue without the CEL coming on, though it typically will). it is highly unlikey the water temp sensor itself is the cause. more than likely it's the connection, dirty wires, corroded harness, etc. the sensors rarely go bad. replacing it with a new one will likely fix the connections temporarily as the contacts on the sensor will be clean but those in the harness will still be dirty and the problem usually returns in a couple months. very annoying.

 

check this thread, i came up with a permanent fix for the water temperature sensor problem, one of the best MODs i've done. excellent pain in the rump roast relief to ease of mod ratio.

http://www.ultimatesubaru.org/forum/showthread.php?t=27923

Well, I swapped the coolant temp sensor with the other one I had and she's idling better. Still rough, but has improved. VAC around 12-13 in/Hg instead of fluttering around 10.

Another thing I should mention is that my Air/Fuel guage is reading an open (full rich) when connected to the sensor. Too bad the o2 sensor is wedged in the cat, I REALLY want to know where that engine is running A/F ratio wise. Guess it's time to mount a new one elseware.:-\

Excelent writeup, grossgary, very good. However, my coolant sensor has a pigtail on it.

Also did a oil change and now my valve tick is back. I can't win.:banghead:

hmm, shall i try and just disconnect the sensor at the top and leave it in the cat and see what happens? car is pinging still real bad and i wouldnt mind a little drop in gas mileage if i can get the ping to go away

I don't know if the o2 sensor would cause pinging, that sounds more like timing and/or bad gas.

Well, I went to a couple of mechanics to see if there was a way to replace my seized o2 sensor and got the imfamous gonna hafta replace the cat line. So, I checked out the cat an it appears it's mainly gutted. I can run a rod all the way through the cat without hitting anything. So, I was thinking can I just drill a hole in the cat an mount a new sensor elseware? Or will that cause the ecu to run more rich since there is some catalyst in the cat?

have run many tanks of premium from different brands and no change..pinging started when cel came on with a 32 code....

you should be fine to mount another O2 sensor in your exhaust.

want to disconnect that o2 sensor this afternoon...can i just snip and cap the wire or do i have to disconnect at the connection on top of the engine?

grossgary:

Are you sure what's left of that cat isn't going to freak out the A/F ratio?

 

starkiller:

If it was me, I'd disconnect it at the conector at the top of the engine.

well, disconncected the o2 sensor at the connector, will see how she runs for the next few days...fingers crossed as the premium gas is killing me at $2.63 gal and with my new job starting soon its a 66mile roundtrip.....

I'm gonna try putting a new o2 sensor either just past the cat or right at the end of it. THat way I can at least re-connect my A/F guage and see where she's running.