Ok guys I got one for you. I have a 98 XJ8 it runs fine when you first start it and its in open loop. As soon as it goes into closed loop is where I have some problems.

It starts idling rough and it runs rough from 1000-2500 once you step into it above 2500 it clears up and smooths out. It also throws a P0175 code on bank 2 being to rich and it goes in and out of restricted performance.

I put a scanner with live data on it and the fuel trims and way out. Please take a look and I have no voltage on my bank2 02 sensor at an idle. I only get a reading from it when I rev it up?? Im thinkin it might need an 02 but dont want to just go replacing them if there not bad.

One other thing to note I had to run more wire for my bank2 02 sensor 2 bc the plug ripped when I was changing the motor. Does it matter as long as the wiring is similar or does the 02 sensor use only the factory wire resistance and I could have messed it up??

shrtft1: 19.5%
longft1: 14.8%
shrtft2: -19.5%
longft2: -15.6%
02 b1s1 volts : 0.000
02 b1s2 volts : 0.020
02 b2s1 volts : 0.960
02 b2s2 volts : 0.775

I dont understand why one bank is dumping fuel in and the other is taking fuel away any ideas??? thanks in advance guys Jeremy

 

I would check the splices on the replacement wire first. If the wire was properly spliced and of equal or better gauge it should be fine. All my automotive splices are 'tinned' and then connected with a crimped uninsulated butt splice and covered with shrink wrap.

I think you know that you need a new O2 sensor so just bite the bullet and install one. Just think how easy the replacement would have been if you had done it with the engine out.

 

testpoint has it exactly right. If the wiring is good, then the sensor is most likely bad- ECU input problems afre unheard of. I cannot exactly explain the cross coupling between the right and left banks, but with a zero input lambda sensor, it really does not matter. Fix the sensor, then consider what else might be happenning.

 

Funny thing the sensor that I rewired is working and reading fine its the upsteam sensor on the same bank that is reading 0.000 until you rev it up. This would still be a bad 02 sensor with this reading correct?

 

Smitty....yours being an US model with for O2 sensors, the 'upstream' ones are heated and should show certain voltage levels at given temps.
The JTIS has this info....if no readings...read that as a dud

Cheers,
Maximus

 

These might help

bob gauff

 

Thanks everyone for the posts. Is it possible I had bad gas? I went down and got some fuel yesterday when I was out reading my scanner on my jag and ever since then the car has ran great and no codes and fuel trims are normal???? The car had sat for a year and a half with the same fuel.

 

Duuuuuh!....Smitty....you have answered your own question I feel.
18 months is a long time for a car to be sitting containing modern fuel....it just does not keep and goes off very quickly.....any fuel should not be kept longer than three months.
Give your car a birthday by running a couple of tanks of premium fuel and add a can or two of high strength injection cleaner....should clear up the problem.
These engines don't appreciate crap fuel!

Cheers,
Maximus