Help!

[XJAnthony]

as you may know, i just put an ignition stater and CPS in my XJ. runs great, but when i hook a matco scanner up to it, the rpm goes all over the place. the tach inside works, and it idles and runs fine. also, when i un plug the CPS while idling, the rpm reading is fine, so any ideas?
it's a 91 HO

[langer1]

as you may know, i just put an ignition stater and CPS in my XJ. runs great, but when i hook a matco scanner up to it, the rpm goes all over the place. the tach inside works, and it idles and runs fine. also, when i un plug the CPS while idling, the rpm reading is fine, so any ideas?
it's a 91 HO
You have the wrong adaptor on the scanner.