Where the harness plugs into the pmd there is a chip inside and mine says 7. I recently had injection pump replaced and when they pulled of the pmd to relocate the tech said it had a chip that read 5 so he swapped out with mine that read 7 is this and aftermarket upgrade with my pmd? In case im confusing everyone he used the new pmd just swapped out the chip.

 

Wow nobody knows what this is for? The tech suggested that the seven meant more fuel??

 

they are calibration resistors that run the injection pump at it's optimum performance. The truck will run without one, #5 works on all injection pumps. I only know this because I just relocated my pmd and have spent a bit of time on the phone with Dave Breggin at BlueHummer Outfitters.

http://breggin-enterprises.stores.ya...t/fsdcare.html

here's aexcert from Chuck's site flashoffroad.com:

If you get a new FSD you will need a new calibration resistor pack for $20. The resistor describes the pump to the electronic control system. The resistor must match the pump, not the FSD/PMD. When I purchased the FSD, there was no resistor with it - I had to buy one separately. I believe that if you get a complete pump & FSD, a new resistor (matching the pump) will be included.

The #5 is considered the "average", and almost any pump will work with a #5 resistor. The resistor is only used when the control computer forgets what the value is, like after the batteries are disconnected. If you don't use a resistor you will get a p1218 error code when the computer tries to read the value.

You can get the computer to see the new resistor by initiating a TDC Learn with a tech 2 scan tool. The computer will check the resistor value on it's own every 50 startups.

 

Thanks I will call dave and ask him about mine I appreciate your input.