Cam/Crank Sensors

[Lonestar10]

Iam unsure as to what all sensors the CM871 has but at probably a 1.05mil miles can these sensors cause any issues without throwing codes? i know in the old 7.3L powerstrokes you'd basically replace the crank sensor yearly cause it could cause misses/poor running without codes. does the same fall into place for the CM871?


so i know it has to be getting a signal from somewhere for the actuators to fire the correct injectors so if you could let me know which sensors it has and if it would be prudent to replace them if i dont have to loose an arm and a leg in the process.

Thanks!

[Rawze]

For a properly de-mandated engine...

turbo speed sensor, crank and cam sensors, Exhaust gas pressure sensor, fuel temp and fuel pressure sensors, IMAP sensor, (water in fuel sensor, some engine), turbo inlet temp sensor, barro sensor, oil pressure sensor.

For a factory Stock engine, add to this, ...
crank case pressure sensor, EGR temp sensor, EGR Delta-P sensor, aftertreatment fuel pressure sensor, DPF Delta-P sensor, DPF inlet and outlet temp sensors, DEF quality sensor, NOx sensor(s), etc etc.

It is not typical for the engine to throw any code for a sensor that is reading wrong. Old, out of calibration sensors will cause fuel mileage losses and often, other issues that never throw any codes unless the readings are severely out of whack. The bulk of ISX owners will go years, loosing tens of thousands in wasted fuel costs because they neglect their engine and its sensors simply because they see no codes in the dash for the poor feedback data.

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I did not mention components like the egr valve, turbo, crossover pipes, Doser injector, etc.etc. They are just as important too.

[Waterloo]

I replaced mine, cam and crank sensor, when I had a funny vibration/sound in the motor pop up, I posted on it here around two/three years ago. The cam sensor on the 871 is next to the Jake sensor on the driver side of the head. The crank sensor is down on the lower forward side of the motor on the driver side. It is the sensor down by the damper. They are around $30 ea +/-, same sensor, so buy two. It did make a difference when I replaced them, the motor did smooth out. I bet they were the original sensors from the factory. Here is the sensor, part number 4921599

This is cheap preventative maintenance.

[Lonestar10]

I am properly the mandated so I guess I just need to replace my cam, baro, and crank sensors and then I should have all the sensors required replaced
Where is the barometric sensor I've seen it on my dad's 870 I haven't seen anything like it on my 871

[Waterloo]

(01-18-2019 )Lonestar10 Wrote:  I am properly the mandated so I guess I just need to replace my cam and crank sensors and then I should have all the sensors required replaced

I would replace, especially if you do not know the age of the sensors. Especially the iMap sensor. Many times like Rawze said, no codes are triggered when these sensors start to fail. No barometric on the 871.

[Lonestar10]

I replaced IMAP EGR differential and exhaust back pressure 3 months agoand I thought I had one because I do have a barometric pressure reading in insite

[Lonestar10]

And is there two cam sensors one for the injection one for the intake and exhaust?

[Waterloo]

(01-18-2019 )Lonestar10 Wrote:  And is there two cam sensors one for the injection one for the intake and exhaust?

On the 871 there is just the one cam sensor on the injection side of the head, nothing on the exhaust side. And the crank sensor down near the damper on driver side. There are only two on the motor. The crank sensor is kind of annoying to get to, and install, just takes a bit of patients to do it. Nothing major, just annoying, you really have to push to get it to snap in to the hole, and it is at an odd angle to get to, you do a bit of pretzeling.

[Waterloo]

If you are going to be on that side of the motor, inspect the oil pressure sending unit, it is below the cam sensor on the block, near the fuel filter. Has the same look as the cam sensor, but is different in function. Check it for oil, they like to weep, and when they start that is a good time to replace.

Same with the Jake sensor, which is next to the cam sensor, in the side of the head, there is a wire clip that holds the Jake sensor in that needs to be pulled straight up to remove the sensor, check for oil weeping visually before touching it, no oil, leave it alone unless you are having Jake issues. If it is weeping it is a good time to replace the o ring in that if the sensor wiring looks OK. If the wiring under the cover looks old and brittle, best to replace that entire harness under the cover.