CTS sensor

Howdy All. Still trying to fix my 87 4.0 . Still having the same hesitation and rough idle problems after all my changes.. TPS, O2 sensor, Plugs , Wires, Cap, Rotor, Intake/ Manifold gasket, Cleaned throttle Body and IAC. STILL GET 9 MPG.. Today I decided to unplug my CTS on the lower side of the block and see what difference it would make to the running of the jeep, it didnt change anything, starts as if it was still plugged. Now does this mean that it not working? If you have a CTS that you know is functioning properly and it is unplugged what will the symptoms be?? Thanks ALOT

Im not sure what it does when its unplugged and the engine is running, however the CTS is very very easy to test with a multimeter. Your going to want to test resistance across the two wires to the sensor. Resistance should be less than 1000 ohms with a WARM engine (examples = 212* would be about 185 ohms, 160* would be about 450 ohms, 100* (not warm enough) would be 1,600 ohms).

Here is a chart to help you:

F (C) Ohms (Resistance)
--------------------------------------------------------------------
212 (100) .................................. 185
160 (71) ................................... 450
100 (38) .................................. 1600
70 (21) ................................... 3400
40 (4) .................................... 7500
20 (-7) ................................. 13,500
0 (-18) ................................. 25,000

-40 (-40) .............................. 100,700

These have helped me out alot
http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm
http://www.pirate4x4.com/tech/billavista/PDFs/Jeep_Renix_Fuel_Injection_manual.pdf

Have you checked the compression yet?