Mechanical TPI Question HELP

[Carter Powell]

Here goes! On my 198? 2.4 EFI BP The mechanical tpi unit on top of the air horn does not reat the correct values according to the mercury EFI testor and manual. It says that it should be at .50 closed throttle and 1.74 full throttle. The manual does not state if this is a resistence value or not. I even went so far as to install a new EFI harness to see if it would change anything, nothing. Next, installed new old stock Rapair mechanical unit, it does not read any different than the old unit which is about .5 to .8 ohms on many different ohm meters. Neither of these TPI units will read anything when hooked up to a merc EFI tester as it appears they should. Everything else reads perfectly on the EFI testor except the TPI units.
What am I missing. The motor runs very rich at low speeds so I thought the TPI unit was out of whack, but just can't figure what is going on.

Help Carter

[Eagle One]

The TPI should be ajustable at idle from 50 to 100 ohms by turning or sliding the TPI in its mounting area. At wide open the reading will be higher. 50 ohms at idle is lean 100 is rich. The TPI should read even if its off the engine. If the ohms don't change while using the ohm meter probes to touch 2 wires(which ones I don't remember but it will only read on 2 of the 3 wires) the TPI is likely bad. Hope this helps.
Eagle One

[steve]

Check your rectifier.