'91' XJ+borla header+propeller shaft=shredded O2 sensor wiring

Wblane did pass the time by typing:

Running without the O2 sensor is not a good idea. The ECU uses it to adjust the mix so your engine isn't going to be running at the proper mix. Could be rich, could be lean, neither is good.

Now if the wires are just frayed they probably still are ok for a while. Mine got fairly badly melted at the clamp that holds them to the engine block. Had to rewrap the wires and route them away from heat.

I use wire loom and zip ties to keep things out of the way.

Doug, thanks for the response, but the wires aren't only frayed, one of them has broken. I just picked up a Bosch replacement O2 sensor. I just hope I can find a long enough zip tie to do the job.

-Bill (remove "botizer" to reply via email)

Wblane did pass the time by typing:

That would then depend on the wire that's broke. Two of them are for the heater circuit. If either one of those are broke you will just run rich for the first few minutes of run time. Can't say for sure since I don't have your years wiring diagram.

Gee, you mean the loose gas cap wasn't really causing the check engine light to come on? Imagine that...

Yeah, you were right, but I thought you and Mike R. (and some other people too, maybe even Bill Hughes) had decided it IS possible for a loose gas cap to cause the check engine light to go on? So can a loose gas cap cause the check engine light to come on or not?

-Bill (remove "botizer" to reply via email)

The Haynes Manual shows a code for the gas cap and emissions system on a '91. If it will set a code, it will trigger the check engine light.

Mike

Wblane wrote:

Yes, the gas cap can cause a Check Engine Light.

Mike R and others think so but it's not the case. 91 XJ couldn't care less if you have a gas cap or not. It doesn't even have an evap system trouble code because it has no means to monitor the evap system.

You're still looking in the wrong manual. 91 XJs do not have the ability to monitor the evap system.

Can't set an evap code, thus won't trigger the CEL.

That is an OBDII DTC Bill. We're talking about a 91 XJ here.

:

The Haynes calls it code 31 for all 1991 and later models.

I thought 91 was when they changed away from the renix system?

Mike

bllsht wrote:

That is correct, 91 was the first year for Chrysler controls on XJ. However, not all vehicles are equipped the same. Just as you wouldn't find an EGR code on a vehicle without EGR, the XJ wasn't equipped with any evap system monitoring capabilities until 96.