I've converted my 03 supercrew to a diesel. I have a 36 -1 reluctor wheel working with me stock crank sensor. Eautorepair shows the tach signal going from sensor to PCM to gauge. I get 425 ohms across the sensor and 14.2 V thru the wires when it's running but no tach movement. I have my stock oil sending unit tee'd in but no movement on gauge. So my tach, oil gauge and fuel gauge do not work. They all function during the test cycle. They peg and fall. I think it's a common issue that is related to a wire that might be disconnected Any help appreciated.

 

Trying to be of help with re-engineering is difficult if it can even be done, not knowing what you've done with the wiring and power.
The dash is all electronic even to the fuel gauge.
It's not old time analogue.
First the oil pressure is designed to work on a switched ground either on or off, from a sensor 'switch' not a sensor that varies it's resistance.
The fuel gauge takes the fuel level arm resistance and converts it to digital in the dash then the output provides the gage reading. So there again is no direct operation of the gage from the fuel tank sender resistance.
In fact, the dash micro processor updates the gage reading in 'time segments' not in real time. This is done for example because no one needs to know fuel level 'all the time'.
Originally the low fuel level lamp came on not when totally out of fuel but with about 5 gal left in the tank. That's something a drive might want to know out on the road between filling stations.
The tach and speedo work in a similar manner.
The best way to see this is in your Haynes manuel pages 12-30 and 31.
It's not all there but a good idea of the signal paths, power feeds etc and what is going on.
In the original application, your dash had a diagnostic ability to read out many parameters such as RPM, Mph, oil pressure range, coolant temp., battery voltage etc. as well as detect some faults.
We don't know if that even works at this point.
If not you will have an ongoing hassle trying to make things work as you want them to do..
Good luck.

 

My Old friend, thanks much. Yeah, I know it is kindof crazy trying to figure out this jumble of stuff. I "trimmed" my harness using my FMC wiring book on the 03 F150. I don't have a Haynes, but I do have a subscription to eautorepair.com that has the wiring also. I got it because it goes into theory and operation as well as diagram. My voltage meter works. In fact, its the only thing working. I know there's more than 5 gallons in the tank. I've used the stock oil sending unit/switch whichever it may be. I was just hoping it would be an ah-ha moment for someone that would say, "The dummy cut this wire!" and I could fix it. As far as I know everything is stock for the fuel gauge setup. The only harness NOT hooked up is the one going to the tranny.

Thanks again, if there's any other thoughts i'd appreciate the help.

 

I borrowed a diagnostic tool from a friend. It indicated no Power to PCM I found the "broken" connection and fired it up. The tach works beautifully. I had to hook the hot wire from the cam position sensor to the hot wire of the Crank position sensor and she works beautifully.