DJBARR

I need some serious help. I got my 96 XJ 4.0 it runs n drives just fine but after I shut it off it won't restart for hours up too a day and I'm at a loss on what it could be. Things I have replaced include (plugs, wires, distributor and sensor, cap, rotor, ignition coil, temp sensor, and O2 sensors) the fuel pump is turning on and I'm getting plenty of fuel pressure at the fuel rail. Air intake is not restricted in anyway. I thought about heat soaked injectors but they are cool to the touch n it still won't start any ideas would be greatly appreciated

EZEARL

Codes?

DJBARR

The only codes poopin up is P0171 and P0172 which is O2 sensors one is running rich and the other is running lean which means I got a clogged cat

Radi

Are you missing spark or fuel?
If I had to guess, I'd take a look at the CPS. They're known to crap out with temperature.

'96 has a lifetime recall on the OEM cat. They break apart internally. Give it a kick, if it rattles, it's bad. Talk to your dealer about a free replacement.

wizardpc

Might be a bad engine coolant temperature sensor. Your 96--I believe, but not sure--has two. One in the thermostat housing used by the computer, and a second one on the back of the block for the gauge. So it's possible that the front one is bad and reporting temperatures much lower than reality, causing the computer to dump the wrong amount of fuel through the injectors (which would cause the O2 sensor codes)--but the back one is fine and showing you the actual temperature.

I had this exact thing happen to me about 2 years ago. $17 sensor, 5 minutes to replace it.

wizardpc

Here is the testing procedure:
https://www.cherokeeforum.com/f2/coo...esting-188821/