Why do CPS sensors die?

[RTFM]

What kills them?
I'm at the point with my 89 XJ 6cyl 5sp where it eats a TPS once a year.
She has 303,xxx miles on her and over heats like the dickens and munches a CPS yearly.

If I can figure out why they die I might be able to - I don't know - what - prevent it from dieing so often....

I love the XJ but I think this is probably the year she goes away - 20 years was a good run, but 303,000 miles is just starting to fall down around her ears.

There's a pretty little 2002 Ford Ranger with 75K just around the corer that's caught my eye - I so hate having to borrow a pick up to haul things an XJ just can't do. But the thought of a new to me truck is foreign after 20 years with the same Jeep.

Was there a point to this post? Yah I guess it was are there know issues that kill CPS sensors? As mine gave up the ghost last night and it is a new year.


EDIT I said TPS I meant Crank Position Sensor.

 

[kastein]

Sounds like you should buy a Comanche...

The only real killers are water exposure, heat, crappy quality, and wear. The more the engine vibrates while you keep the throttle mostly in the same location, the more it'll wear in that one spot.

Overheating - when does it overheat?

 

[RTFM]

OK Do have a heck of a vibe right at 2K rpm - have for years and years.... possible issue.

Overheat is hot months on vehicle slowing to a stop, even with thermal switch turning fan on, and me placing ac switch on to add E-fan - 3 ear new metal tank 2 pas rad, pump, hoses, replacement overflow tank with Mac Radiator Diamond plate tank and Accel pressure cap - it will ALWAYS go to red line on a stop light, just as soon as it starts moving the tempo falls and resumes normal operation range.

Was thinking of putting hood vent (labaron'esque) in this year and quite possibly change to open system also.

But that's another day - and has been covered here to death, it just that darn CPS once a year - every year.

It's more a road queen than a 4x4 daemon so excessive dirt and water should not be too much of an issue though it is used for "sportsman access" managed/un-managed dirt roads in southern Idaho and Northern Utah / Nevada so dust YES

 

[kastein]

#1 on CPS death I'd put as heat related, #2 as quality control issues, #3 as corrosion (stuff tends to migrate into auto electronics through any crack, however small, I've even seen it creep in between wire insulation and epoxy potting compound.)

I'm stumped on the cooling issues. Make sure the new pump has the blades going the right direction?

 

[RTFM]

Heat issue - TBD for another day - CPS sometime this week I'll do the dirty deed and pull it.

This one was purchased through 4wd.com next one will be Rock Auto see if that makes a difference.

 

[birchlakeXJ]

I worked for a division of Honeywell for 23 years, where we along with other things, manufactured OEM sensors for the automotive industry.

There can be a very big difference in "reliability" between manufacturers of sensors.

I buy plenty of aftermarket parts, but I purchase my crank sensors DIRECTLY from Jeep and have never had a problem with those.

I have however, had POOR luck with aftermarket crank sensors.

You get what you pay for with this automotive sensor. Buy one from Jeep and see how that one holds up. Worth the extra money.

Just to be sure here though......Have you actually tested the failing crank sensors to ensure they are bad? Some resistance inside of one of the connectors can inhibit the signal from making it to the computer, making it look like a failed sensor. Be SURE that the crank sensor connector is clean. Spray it with electrical contact cleaner. Then add a small dab of dielectric grease and reconnect.

 

[tommyr]

X2 on the heat. Had the one on the ZJ crap out. Ran like poop. Once engine cooled, started right up and ran fine. Someone on here mentioned pouring water on it to see if it was getting heat soaked.

 

[RTFM]

Heat soak may be the initial death and after hours of setting it MAY start or may not.

Some times on the next morning it will start, some times not. I do find it does not want to start push in neutral pop clutch to move sensor disk CPS is looking at and then it will start (or not...)

Connections look clean up top but did not put dielectric grease in - will also do this time around and will also look in to Jeep CPS - I just loathe the local dealer - hes a grade "A" D-Bag.

 

[nnvaxj]

not cps related but overheart at stoplight was cured on my 90 xj with upgrade/replace dead mechanical fan hub with hd hub 4 grand cherokee search for heavy duty fan clutch for grand cherokee like 60 at napa

 

[RTFM]

Yup Had that conversation W/ Joe Peters last year and put it on this years to do list.