7.3 IDi Tachometer sensor

[Spun4Fun]

I been watching my 7.3 IDi Tachometer for the last few weeks , When i start the Truck and warming it up some times the Tech read 0 and wont register and some times with fast Idle it read like it should , Today it remain 0 but once i start moving the Tech jump's right up and read like it should .

Is this normal ( i don't think so ) do i need to replace it , If i choose not would it effect any thing , Truck ride the same , shift the same . Is this truck ECM smart enough to detect the Tachometer sensor .

 

[franklin2]

The wires going to the sensor like to go bad. Wiggle them around and see if it makes it quit and then work.

 

[yARIC008]

http://www.ebay.com/itm/Ford-6-9L-7...NEW-/201237302469?hash=item2edaad8cc5&vxp=mtr

Here is a new one.

If you have an E4OD, then yes, it will affect the transmission. The tach signal goes into the PCM first for processing, then outputs from there to the instrument cluster.

 

[dunk]

I have a used tach sensor I can test. If it works $25+the ride?

 

[Spun4Fun]

Wiggled the wires with no effect .. I started to drive today and came to a stop and the Tech regestered my idle speed and acted normal .


My O/D some times decided to flash when the truck is cold that's all along the fact that I believe the Tach setting at Zero but I have to pay close attention next time it happen , writhing few minute in the drive it goes away ( I just went thru the tranny and I know it's solid) it shift perfect .


Am wondering if my Tach sensor on its way out and trip a code in the TCM ...!

 

[Spun4Fun]

I have a used tach sensor I can test. If it works $25+the ride?

Nice ... $25 + the ride .. Lol where you located unless you mean + shipping

 

[dunk]

That would be +shipping. Just threw it in the truck and my tach read erratic, then back to normal with my sensor. Sorry, no better than yours.

 

[tbrumm]

Take the sensor out and clean off the "eye" on it. It gets gunked up over time. May not solve the problem but worth a try.

 

[TahoeTom]

http://www.oilburners.net/forums/showthread.php?70490-Tach-Sensor-Fix!
This was in the tech articles. I have not done this myself. Your results may vary.

 

[BDCarrillo]

That fix works, but not for serpentine setups. Verified on my trucks.

 

[Spun4Fun]

Yah my truck is Serpentine belt .. Just curious why it wouldn't work ..?

 

[IDIoit]

in serp setups you dont have the room because the vacuum pump is in the way.

 

[BDCarrillo]

I've looked high and low for more compact sensors and even reached out to a few manufacturers without any luck. It's a simple permanent magnet with a copper coil around it, and the gear teeth passing by induce a very small AC current. The frequency is read by the tach driver.

The OEM units suffer from moisture/contaminant penetration through the wires leads. I've had some success ultrasonically cleaning them with mild solvents and then sealing the wire openings.

 

[dunk]

Should I not trash the erratic one I have? I don't feel like messing with it but if anyone want it you can have it for shipping. Reads a bit bouncy at idle and doesn't't read over 1500 RPM or so.

Also if failure is from moisture would it be prudent of to silicone where the wires go into the sensor?

 

[BDCarrillo]

Send it to me, I'll fiddle with it on my test rig. Pm sent with details.

Silicone or liquid electrical tape will work great on your new one.