1991 Oldsmobile 98 Camshaft position sensor

1991 OLDSMOBILE 98
90,000 MILES • 6 CYL • FWD • AUTOMATIC
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HTD50904
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Where is the camshaft position sensor located on the 3.8 liter engine and how do I repair or replace it?

My grandson replaced the waterpump and I suspect with his rough handling he knocked the magnet out of position.

Thanks in advance for your help.

updated 11/5/09
The dealership said there was a magnet that was close to the water pump that was knocked out of position when my grandson changed the water pump. Do you know anything about this magnet?
Oct 27, 2009 at 8:33 PM
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RASMATAZ
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Hi there htd50904 and TY for the donation Did you came up with DTC 41? Inspect the sensor open it up and also check/test the wiring The CMH sensor is located on lower left side of engine, above lower pulley See below location E


https://www.2carpros.com/forum/automotive_pictures/12900_cmh_2.jpg

Get out your fluke meter and investigate what's happening on the wires going to the cam sensor. Take it back out and magnet the bottom of it to see if it does something. The cam sensor is a switch that likes to ground a ref. wire from the BOX. It can ground that wire really fast and not get tired. It needs two wires to work. The third wire is the wire it grounds. That wire might be like 5 volts or zero volts depends on how close the magnet is. Some cam sensors has got their own magnet. So they work by a metal object getting close. When the metal object gets close, it causes the magnetic field to change shape. The change in that shape causes some magic to occur in the sensor which = the grounding of that wire. The computer puts out that 5 volts on that ref. and has eyeballs that can see when the 5 volts goes low. That up and down business makes a signal. If the computer is pretty smart and can make good sense of that up and down stuff it will fire the injectors, turn on some relays, make the needle move on the tach. So you got figure out if it is making the signal and perhaps if that signal is getting to the BOX. If the 5 volts is gettin to cam sensor, then the up and down stuff is too. The cam sensor needs the other two wires working too. One of em is going to a ground. The other is power. It might be 8 volts or other numbers. It depends on what you messing with. check harness behind alternator...oil soaked, insulation deteriorated or rubbed through
Oct 27, 2009 at 9:15 PM
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RASMATAZ
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Once again a code DTC 41 will be automatically set if there's a problem with the camshaft sensor are you getting this code? -3.8L engine has the CMH in the distributor.

Also if there's a problem with CMH the fuel injector/s will not be energized and no fuel to the cylinders

I'm not too familiar with this engne as per location I got this data from Mit1 and Alldata auto references-
Nov 5, 2009 at 3:24 PM
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