wrong CPS??

while trying to get my non-starting 87 to do the right thing.. i installed an old but unused CPS for the 89 XJ i had a few years back... i have been suspecting that it may not be compatible with my 87... a call to the parts chick at the stealership didnt give me a solid answer so i went ahead and ordered a new one... my memory is shaky on the 89 and my XJ knowledge wasnt much back then so actually sent it to the dealer when it wouldnt start..
anyone out there know whether the unit from my 89 4.0L auto is compatible to my 87 4.0L 5 spd? the plug is the same...
thanx
mike

i would go to carparts.com or some other online parts cite that gives part numbers, put in the info for both vehicles and see if the numbers match.

I checked with AZ, on the same issue, and part. They have two different part numbers for the 87, and 88-90 CPS.

i got the new one from the parts chick. it'll be in tommorow.... i hope its my answer....
mike