If you are talking about the one that takes a 1" wrench with two black wires, That would be the Tachometer sensor.

-Enjoy
fh : )_~

 

ok, thanks a bunch.

 

The top one is the vacuum sensor that Dave S refers to in his earlier post. The bottom one is the tach sensor, if your tach isn't working right, it can be that sensor. It can also cause the tranny to act up, as it also relays info to the tranny control. (On E40D's.) If it's pooched, it's a dealer only item though.

 

The sensor in the last pic, by the oil fill, is the tach sensor. The one in the first pic is the baro sensor that Ford Trans Tech was talking about I think. Does you new truck have an autto tranny?

 

My map is in the console between the seats.

 

disregard ...............I hit the wrong button,somehow

 

That is the tach hook up for these engines. The loose and frayed insulation is the leading cause of failed or poor reading tachs.

 

Sorry didn't see that there was a second page lol.

 

ok, thanks. the wires are frayed, but the tach is working. still trying to figure out why this thing runs like poo

 

No, this is not the low-vacuum switch - what you have in this picture is the BARO sensor for the PCM, the low-vacuum switch looks kinda like a small tuna can, and lives on a large flat metal plate bolted to the passenger-side inner fender several inches behind the battery.

This is your engine speed sender, it drives the tachometer on the dash and also feeds into the PCM that controls the transmission, again for shift schedule purposes.

 

Smartass - my map is on my windshield, it adjusts to my location automatically too But really the sensor in question is not a MAP (manifold absolute pressure) sensor, as it's not reading vacuum off the intake manifold like it does on a gasser truck - instead it reads the ambient pressure, hence why it's a barometric sensor.

 

should the hole on the baro sensor be cleaned out? i looks plugged to me

 

Actually mine has a white plastic funnel-looking thing at the end of that port, and the hole in it is clean of dirt and grime. How you'd clean yours I dunno tho, you can't just poke through the nastiness cause it will then end up inside the sensor... if it were my truck and the trans shifted fine I'd probably be tempted to just let it be as is for the time being, then replace it with a clean junkyard unit whenever I found one.

 

it dont shift that great to begin with. i bought this as a future powerstroke build, but i might leave it like it is depending on if i get everything else straightened out. take a look here... https://www.ford-trucks.com/forums/9...out-there.html

 

Think the sensor your pic shows is on the housing just in front of the injector pump and is the sender for the tac in the diesel.
OOPS, realized that this was already answered on next page of post