I never replaced a cam sensor but the crankshaft position sensor's air gap is critical. New Chrysler sensors used to come with a paper spacer stuck to the end. It set the gap and just slid off the first time the engine was cranked. Some aftermarket sensors have a plastic rib molded onto the end that wears off very quickly. That rib sets the gap initially. If that type of sensor is removed and reinstalled, the remaining part of the rib is supposed to be cut off and the paper spacer is used. I used to cut those paper spacers in half and just used one part so I could save the other part to use on another engine. You can get the spacers at the dealer's parts department. I don't know if they're available at other auto parts stores.
I did read where one fellow found that his new sensor was broken because he didn't use a spacer and it hit the outer ring on the flexplate.
I have a '95 Grand Caravan, and until a few months ago, I didn't even know it had a cam sensor. If you want to try to test it and the crank sensor, the feed wire to both will have either 8.0 or 10.0 volts with the ingition switch on. If it is missing, unplug the two sensors and remeasure to see if the voltage comes back. The Engine Computer will shut the power supply down to protect it. You'll have to cycle the ignition switch off and back on to reset it. If the voltage disappears again when one of the sensors is plugged back in, it is shorted.
If the supply voltage is there, measure the ground wires. Expect to find 0.2 volts. If it is a lot higher, look for a break in the wire or a corroded splice. The signal wires are harder to measure with a digital voltmeter because the display will bounce around a lot. If the voltage stays solidly at 0 or 5.0 volts, that sensor is likely not working. A better way to tell if the sensors are working is if you have access to one of the Chrysler scanners, they will display "yes" or "no" for each sensor to indicate if the signals are being received during cranking. I use both the DRB2 and DRB3 scanners. You can find the DRB2 at car show swap meets or on eBay for not too much money. The DRB3 is overkill for most people's needs but they are available over the internet or from the dealer's parts department. The newer models will only work on vehicles back to 1998. To go back further, there is a plug-in card that lets it work on cars back to 1994 and all brands of cars 1996 and newer with the OBD2 emissions system. A different card lets it work on just Chrysler products back to 1983 models. The DRB2 uses plug-in cartridges which are different for most years. The last "Supercartridge" covered all years of all domestic cars and trucks up to 1994 models, but that '94 cartridge works fine on my '95 Caravan.
I'll hand you back to Docfixit. I didn't mean to butt into your conversation. Just wanted to add a little info so you had something to check while waiting for his reply.
Thursday, June 10th, 2010 AT 10:47 PM