Engine Sensors

Hello. My trail rig is a '92 XJ with a 4.0L HO. It has almost 200k and I'm looking to replace the critical sensors for added reliability on the trial. I realize that some failed sensors may result in a completely dead engine (i.e. crank position sensor), while others may only cause a rough idle. Which sensors are most critical? Also, what is the life expectancy of the main computer? Thanks.

OlyJeep

I'm speaking in generalities here. Exceptions exist here! They always do don't they??

Critical: Can leave you stranded: Crankshaft position sensor, camshaft position sensor, fuel pump (not a sensor obviously but something to consider depending on miles on yours)

Driveability/starting issues: Throttle position sensor, Idle Air Control, Engine Coolant Temperature, Upstream oxygen sensor, MAT and MAP sensors.

The computers in the XJ are very reliable. I can't tell you how many guys have changed out their PCMs only to find that the PCM is fine and their problem is a sensor or wiring or fuel delivery problem or some other strange circumstance. I don't think there is really a "life expectancy" for the computer. None that I've heard of anyways.....

I carry a spares electrics box with the following

CPS, TPS, OXY, Injectors, Fuel pump, MAP, IAT.

In the future I would like to include a coil as well.

Good call on the coil goodburbon, forgot that one. Sometimes they get "flaky" and sometimes they just die. Good spare to have.....:spin1:
Oh, and don't forget about the basics like cap/rotor/spare wires. They are responsible for lots of driveability problems.

birchlakeXJ said:

I'm speaking in generalities here. Exceptions exist here! They always do don't they??

Critical: Can leave you stranded: Crankshaft position sensor, camshaft position sensor, fuel pump (not a sensor obviously but something to consider depending on miles on yours)

Driveability/starting issues: Throttle position sensor, Idle Air Control, Engine Coolant Temperature, Upstream oxygen sensor, MAT and MAP sensors.

Click to expand...

X2

With the engine running, start disconnecting things.....

if it's critical, you'll know

add a spare fuel pump relay to your spare parts/carry list

Jeff

Thanks everyone.