Only channel 6 and 7 have internal pull up.
Channel 0, 1, 2 and 5 are 0-5v input (no pull up)
Channel 3 and 4 reserved for EGT1 and EGT2
Not all are connected to EC18 and will depend on your box. Check your cheat sheet that came with your box.
I would agree with Kamuto, use a three wire transducer (+5v, Ground and signal).These type of transducers have a signal conditioning circuit built into them, this will give a 0.5-4.5v linear output. No pull up required as the transducer outputs a voltage signal, rather than a ground signal.