Mx-5141 Jamming after messing with saddle stitch staples

[danny464]

Mx-5141 with Mx-fn10 with saddle stitch. Client tried to change saddle stitch staples but said a little black part came out(picture included) and after putting the new staple cartridge it would still say add staples. I tried to find where the black part goes but was having no luck, I even looked at another finisher with saddle stitch but could not see it anywhere.
I removed the new staple cartridge and tricked the two sensors in the saddle stitch to see if the sensors were working. After I tricked them(using my fingers to trigger them) it detected the cartridge and the saddle stitch started moving and I noticed it was feeding some papers even though there was no job. I stopped the machine and figured since the sensors are good ill just have to figure out where that black part goes or replace the saddle stitch but as I was about to leave I ran some tests and now it was constantly jamming(jam code fppd1_n). It jams probably 9/10 times. I turned it off and on and disconnected and deleted all jobs but issue persists. Another weird thing I noticed is that the machine will still try to print even though I separate the finisher from the copier(still connected just separated). It will print and the paper will jam right before exiting the mfp into the finisher and give the code it always gives. I was running late so I had to leave but ill be going back early tomorrow. Im pretty worried since before I got there the client was still able to use the finisher just not staple but now I told them the whole finisher is giving issues so they are using the right exit tray but they are a church and need the finisher.
If anyone can help me solve the issue ill venmo them $15 so you can get a pizza on me and will Match $15 for copytechnet
(The pic of the saddle stitch I included is one in working condition, felt it could help someone guide me on where the black part goes)

[mojorolla]

That piece is the sensor flag telling the machine has staples installed. Re-install the flag (ugh) or replace the staple cart base. On this model, after the staple cart is changed, the machine will send a page through and staple it in three places to prime the new staple cart.

[danny464]

That piece is the sensor flag telling the machine has staples installed. Re-install the flag (ugh) or replace the staple cart base. On this model, after the staple cart is changed, the machine will send a page through and staple it in three places to prime the new staple cart.

thank you for the reply! Does the sensor flag go around the bottom or the top of the cart base? I could not even see it in a working finisher