Ok. Lets see if I can do this while driving through the Starbucks Drive-Thru.
The RTD sensor is a heat monitor probe that monitors the heat inside the main exchanger. It is located under the front-lower cover. When you pull the cover you will see a plastic black box about the size of a deck of cards. Coming out of the bottom of that black box is a stainless-braided wire that leads to the front of the heat exchanger where the sensor is screwed in with a compression-crush fitting. If you order a new sensor, order two just in case you screw it up on install. I now have an extra one sitting around just in case. You can get new brass compression orings at ace hardware.
Before you start pulling RTD sensors I would first pull the codes out of your 870’s brain and see if there is anything flashing. You do this by grounding out the pink wire pigtail and counting the flashes of the check engine lights. You’ll need your manual to translate the codes.
Another place to start is to make sure you have enough fuel pressure off the pump.
Scott Harlib with
Legend Brands is a great guy and really knows these machines. Gicr him a call and most likely he can get you going again if you need more help.
Im not checking for typos. Im driving.