Could it be my CPS??

[Outdoorsman124]

My '99 5.0 Mountaineer has not been taking the winter too well. Recently, I've noticed the infamous "chirp". The squeaking was really loud a few weeks ago but I JUST replaced the serpentine belt and it got rid of the noise for a while but these past few days have been in the teens down to the single digits and I park outside so I'm not sure if the squeak is just the cold weather taking a toll on the old car or if it's something more serious. In addition, my fuel economy has dropped drastically (~3-4 MPG) since I noticed the chirp. This leads me to believe my Camshaft Position Sensor is on it's way out. Correct me if I'm wrong, but doesn't that sensor control fuel/air mixture to the engine?

 

[koda2000]

it could very well be the CPS. and while i don't know exactly how the CPS effects fuel economy, it's telling the PCM something regarding the valves so it certainly could have a negative impact. it's a pretty common problem with these engines, but not too hard to replace. you'll need to borrow a tool from the parts store to set the new CPS in place correctly, although some have reported changing theirs w/out the tool i wouldn't recomment it.

the CPS is located on the front center of the engine above the water pump. see if you can determine if that's where the "chirpping" is comming from, as it could also be a idler, tensioner, or other pulley bearing going out.

 

[Outdoorsman124]

it could very well be the CPS. and while i don't know exactly how the CPS effects fuel economy, it's telling the PCM something regarding the valves so it certainly could have a negative impact. it's a pretty common problem with these engines, but not too hard to replace. you'll need to borrow a tool from the parts store to set the new CPS in place correctly, although some have reported changing theirs w/out the tool i wouldn't recomment it.

the CPS is located on the front center of the engine above the water pump. see if you can determine if that's where the "chirpping" is comming from, as it could also be a idler, tensioner, or other pulley bearing going out.

Thanks for the reply! I did just replace the idler pulley. I will look into the location of the chirp. As far as repairing the sensor, how long does that usually take and what am I looking at for cost?

 

[koda2000]

Thanks for the reply! I did just replace the idler pulley. I will look into the location of the chirp. As far as repairing the sensor, how long does that usually take and what am I looking at for cost?

RockAuto lists cam position sensors from $12.51-$60.79 (plus shipping) best seller seems to be around $18. the sensor itself is easy enough to change. the time it takes to change it depends on what's in your way. i don't think it takes very long... maybe someone else in the forum has personal experience with this repair. also check for a Sticky on this forum for additional

info.http://www.explorerforum.com/forums/showthread.php?t=161590

 

[Needmopower]

Just wanted to share that I was able to change the cam position sensor without removing the intake manifold on my 2000 4.0 ohv
Basically removed the passenger side tire and lowered truck onto a jack stand then pretty much laid across the top of the engine. Using a flash light and mirror located the cps on the back of the block about 8 inches below the ignition coil. Using an extension and a 5.5mm socket it was easy to remove, had to wiggle a little but comes off by pulling straight up. Put the new one on which will only go on one way and hand tighten the screws as much as you can, this was the hardest part but the screws do turn easily just need to find the right angle. Then again with the extension tighten it down, plug it back in, if you haven't done so already reset your PCM.
So it can be done, took me about an hour. Good luck!

 

[jremington59]

Someone on here had a thread about "greasing" it. I took off the sensor and put a gob of lithium grease down inside and it's been quiet for over a year now.