Typical CPS Failure Milage?
 

At what milage are you guys having to replace your CPS?

i was at a stop sign this morning and my jeep just stalled, it started right back up again but I need it to get back and fourth from school.

Anyhoo, i what mileage is typical for the CPS failure?

-Kyle

I've never replaced a sensor except coolant temp in 100,000 miles.

I'm sitting right at 93k, and I've gone through an ignition coil, 2 oil preasure sending switches, and my water temp guage acts funky at times. Anytime I'm done under the hood, I must make sure the connection at the thermostat housing is angled correctly or I won't get a reading.

whats a cps? something position sensor?

crank position sensor.

-Kyle

I am at 229K and have not changed it out yet. I plan on it, because it does not look that expensive. I have had to change out my neutral/backup switch though and now my reverse lights work.

Just bought my XJ with 133k on it last week.. a day or so after it stalled once, and grew worse rapidly over the next few days.

it just one of those things you have change every so often, like every 2-3 years, that about as ling as mine lasted, mine an 87 with about 190k

Your 89 has a NSS? Mine doesnt...

Just did mine the other day 160,000 miles make sure you do it your self will save your self a s**t load of money. Also sounds like the same symptoms i had. Check the wire on the sensor mine was all dry rotted and burned from hanging by the manifold and the bare wire would short out on the intake maifold

What are some symptoms of a CPS going bad?

Per reports from the field and assorted Jeep techs, I've got a consensus of 150-180Kmiles (RENIX) and 250Kmiles or so (ChryCo.)

It's more a pain than technical - just because of the location of the thing. I've found it handy to notch the CKP bracket using a cut-off wheel in a Dremel hand tool to make it easier next time (you don't have to take the screws out next time if you do it properly - loosen them a couple of turns, pull the old sensor out up top, put the new one in, then nip the screws up.)

The CKP signal is used to generate basic timing signals for ignition and fuel injection timing afterwards, so you can sort out the symptoms from there. Stalling and Crank/No Start are common indicators that the thing should be checked.

When you turn the key to on, the PCM turns on the ASD and Fuel pump relays. You should hear the fuel pump run for a couple of seconds. The ASD and Fuel pump relays then turn off after a couple of seconds.

As you crank the engine with the starter, the PCM reads the CPS signal. If it reads a signal, the ASD and Fuel pump relays are turned on again and the engine starts. If it does not read a CPS signal, the ASD and Fuel pump relays remain off and you do not have ignition, nor injectors nor fuel pump and the engine cranks but does not start.

Like any thing electrical, it can quit when it wants to. There are no set mileage limits.

To elaborate on ET's nice explanation, what happened to mine was the engine would just quit, tach drops to 0 really quick. All electric, etc remains normal. At first I cold just re-start, but then it wouldn't crank at all for a couple tries, then it would crank, but not fire right away and CEL would illuminate, but go out as soon as the engine fired up as normal. I got a CPS at Advance Auto for $67 and spent about an hour in the rain switching it out.. you WILL need a couple of longer extensions and a wobble socket.. I used an 11m deep socket.