legacycentral bbs

Hey guys. It's been awhile, I've been busy with life and what not. My TPS recently took a dive and I couldn't find any good used ones that were in spec, so I said F it and bought a new one. I got the NEW sensor from Premier Subaru/ Subarupartswharehouse.com , I've bought many parts from them before and have never had any problems. I got the NEW TPS installed and set the idle switch to FSM specs, then tested the resistance to FSM specs. Pins 2-3 is 10.46 K Ohms (supposed to be 12 K Ohms), Pins 2-4 fully CLOSED 10.02 K Ohms, fully OPEN 2.32 K Ohms. FSM spec for fully OPEN is between 3-5 K Ohms and fully CLOSED between 10-12 K ohms, my new one seems out of spec already. I personally have tested at least 8 different TPS and have never seen one read 12 K Ohms between pins 2-3, I've also never seen one read between 3-5 K Ohms fully OPEN.

Has ANYONE ever seen a TPS read to FSM specs? Do I need to send this TPS back and get another? Also, none of the screws have EVER been moved. I even tried the NEW TPS on another TB and it read the same as the one on the car. Any help would be much appreciated.

Thanks, Brian

P.S. I'll be posting some pics soon of some stuff I've been up to, more FMIC pics with bumper off I found, turbo comparisons VF11,TD04,VF8,TD05,GT30R(maybe some Q's about this one for y'all), New tint installed, ICE Clay Bar Kit results, none-rotated EWG setup w/ TIAL 38mm and GT3076 (all bolt on), ect.

I got everything put back together and it works fine. Resistance changes VERY smoothly from closed to WOT, it still bothers me that it's out of spec from the FSM. Voltage also transitions VERY smoothly. So there are no flat spots at all, and the idle is perfect.
Kinda upsets me that the used ones I tested were pretty close to this but still out of FSM spec. They did have some flat spots in transition and pins 2-3 were ranging anywhere from 7.5-9 K Ohms, but pins 2-4 resistance was pretty close to the new one I have.

Is the FSM specs correct? Has anyone ever seen a TPS meet all the FSM specs, even brand NEW OE ones? ANYONE?

Brian

I always found the TPS specification, and in fact MOST automotive resistance specs, to be more of a guideline than anything concrete. I prefer to compare readings to a known good unit whenver possible. Honestly, your specs are more than close enough to be satisfactory, and don't forget that ambient temperature can affect resistance.

Thanks, I just wanted someone's opinion on this. I didn't realize the ambient temp changed resistance, good to know. Ambient temp has been around 95* F and 105* F with heat index. I was just expecting this thing to be spot on the specs since it is a NEW OE TPS.
Thanks for the reassurance, I'll sleep better now.

Brian

You already figured out it's fine, but I'll just add a little tidbit of info here:

The actual resistance of the TPS is not crucual. The ratio of resistance between pins 4 and 3 and pins 4 and 2 are what matter. That's what the ECU ends up measuring.

Thanks vrg3, hopefully this will help fill in some of the gaps for someone in the future.

Brian