97 Taurus 3.0 Vulcan Cam Position Sensor Function?

The second cheapo little plastic rotor/magnet in the cam position sensor apparently has failed again in my 3.0 Vulcan at 126K. The original one failed about two years ago during a period of very cold weather (brittle fracture?). Explains the hi rep rate tapping I recently heard that has since gone away! Outside of the OBD II P340 code and the resulting check engine light, the car is running fine.

What function does the cam position sensor serve in this engine? I will be changing it as soon as I have time to get under the hood, but like I said the car is running fine w/o it. I'm assuming the engine managment system is using a default value for the sensors output while it's failed.

Chris Bowne Stonington, CT

Reply to
Chris Bowne
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I am not 100% sure about the purpose of the cam position sensor for a Contour V-6, but on a GM V-6, the cam position sensor is import for rapid starting. The PCM can't use just the crank position sensor to determine whether the #1 cylinder is on the compression stroke or the power stroke. When you add the cam position sensor input, the PCM now knows for certain which cycle the engine is on. This is important for engines that use sequential fuel injection. Unless the PCM knows which stroke the engine is on, it cannot reliably inject the fuel at the right time. Most PCMs include a back-up strategy that will allow them to determine which cycle the engine is on without the cam position sensor, but the engine has to turn over for a while before this can be done. Therefore the engine has to be cranked more before it starts. Once the engine is running the cam position sensor is just a back-up that isn't very important (at least on a 3.8 GM V-6).

Ed

Chris Bowne wrote:

Reply to
C. E. White

When changing the sensor, check the "driver" very carefully. It looks like a little distributor. I have seen quite a few break the sensor because the driver was worn out. When changing simple mark the old one on the intake and mark the rotor position. Then put the new one in the same way. GL

Reply to
Scott M

IMHO you don't need it. I don't know what funtion it has, but my 96 and my

97 taurus's have been running great for 2 years without it (about 60,000 mi each since it went bad) . Gas mileage is still averaging 25mpg, they purr like a kitten. I did clean out all the loose broken parts from the housing, however. My shaft was bad, so I went no further because they both had over 150,000 mi at the time. But, do what you want 'cause you will anyway.
Reply to
ProudPapa

in article snipped-for-privacy@corp.supernews.com, Chris Bowne at snipped-for-privacy@riconnect.com wrote on 12/17/04 7:13 AM:

Well Mine has been broken for 3 years. It may cause the car to run a bit lean. The sensor does exactly what it says. It tells the computer the postion of the cam prior to coil firing. The biggest issue is state emmision inpections. I can't pass till its fixed they say.

Reply to
Tiger

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