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Crank Position Sensor

Ecarlcl

NAXJA Forum User
Location
Huntington, NY
How much does a crank position sensor for a 90 4.0 cost? I want to replace mine for as a preventitive measure. Thanks

Ecarlcl
 
Or you can go to the dealer and buy it. I think i paid between 40 and 50 bucks for one but there is a little known secret. On the 87-90 XJs there are two CPS to choose from. There is the standard one and the high alt version.

The standard works well at normal altitudes while the high alt gives you more advance so when you are in mile high city you don't have a major loss of power.

Also with our series of XJs, I own a 88 XJ, there is a knock sensor so the engine will retard the timing if it begins to ping. I can see no down side to installing the high alt CPS. At my dealer the standard and high alt were the same price, so more power for no additional cost... that a no brainer.

When you go to the dealer ask for Part number 53005421
 
Well my 90 was bought brand new in Dnever, so It has all the high altitude stuff, that explains why it pings on cheaper gas in KC. Thanks

Ecarlcl
 
You don't have to seperate the engine and transmission to replace these do you?
 
Nope, it bolts to the bellhousing, you can reach it but its a stretch.

Mike
 
Ecarlcl,

If you are getting pinging with 87 octane then you need a new knock sensor. They are now available at parts stores, a couple years back it was a dealer only item.

You will find it on the driver's side of the block just above the oil pan and around cylinder #2. The old one will look like an oxygen sensor, has a white shaft and a fuel injector electrical connector. The new one looks like a little doughnut, here a pic of the new knock sensor http://www.partsamerica.com/product_images/img/NIE/DKS111.jpg

I looked and advance auto parts sells it for $65, I think I paid around $70 at the dealer for mine. So if you are running mid grade at 10 cents more per gallon then after approx 700 gallons of gas the sensor is then making you money. At 20 mpg that means after 14,000 miles. Depending how much you drive that could be a year or two.

Either way replace the knock sensor, sounds like your's is dead.
 
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