Testing a CPS from a 97 that is running rough

I've read all the posts I can find and they all show pictures of a different connector than I have.

http://picasaweb.google.com/lh/phot...authkey=Gv1sRgCLrT19HJpbmktgE&feat=directlink

I'm not sure of the orientation so I don't know which are pins A, B, and C, but the resistance beween one outer pin and the middle one is 4.37Mohms, and the resistance between the middle and the other outer pin 16.67Mohms.

My truck is running rough, and occasionally hesitates on acceleration. When the engine hesitates I simply have to let of the gas, and then push down again and acceleration is back to normal. Takes a few seconds to start when cold. When warm it starts right up. I've tried the on-off-on-off-on with the ignition to prime the fuel lines for the starts and it doesn't really appear to help.

Some more specs: 150K, AW4, 4.0, idles rough but drives fine. I've replaced the plugs, cap, wires, oil, air filter, thermostat, water pump, and oil. I've done a compression and leak down test and discovered on of the cylinders (#3) has a slight intake valve leak but not too bad.

Soooo... do the above resistance numbers sound like a bad CPS?

Thanks,

Mike

mikeprince said:

(1) -My truck is running rough, and occasionally hesitates on acceleration. When the engine hesitates I simply have to let of the gas, and then push down again and acceleration is back to normal.

(2) - Takes a few seconds to start when cold. When warm it starts right up. I've tried the on-off-on-off-on with the ignition to prime the fuel lines for the starts and it doesn't really appear to help.

Click to expand...

(1) Possibilities - TPS failure, dirty Idle Air Controller, dirty injectors, bad Coolant Temperature Sensor, bad coil.

(2) Common, usually a bad check valve. New fuel pump assembly is the cure, or just live with it.

Bad CPS usually means the engine cranks but will never start.


Note the "key" on the top.

TESTING PROCEDURE 1991 – 2001 4.0L H.O. engines
1. Near the rear of intake manifold, disconnect sensor pigtail harness connector from main wiring harness.
2. Place an ohmmeter across terminals B and C (See Image). Ohmmeter should be set to 1K-to-1OK scale for this test.
3. The meter reading should be open (infinite resistance). Replace sensor if a low resistance is indicated.