Need help ID'ing what Nissan/Infinit this TPS came from?

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Bitter
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Car: Uhhhh 2000 Celica, it's....complicated.

Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Thu Jan 14, 2021 6:49 pm

So long story short I've got a TPS that I need to ID the vehicle it's supposed to be used on so that I can get the correct wiring order to use it on my Celica (aftermarket intake manifold, big runners etc), because everyone loves the Q45 throttle body. Thing is, this isn't a Q45 TPS despite mounting to the throttle body...as far as I can tell those have a connector on the sensor body for the close throttle switch (tells the ECM to start idling) and a separate pigtail for the TPS sweep. This sensor seems to have a sweep but I get two different ranges depending how I probe it. The number stamped into the steel plate on the bottom of the unit is A71-600 P21, pictures of the sensor are attached. The connector looks similar to what is supposed to be for a SR20 TPS, but the rest of the sensor looks nothing like that. Obviously I Googled the part number but that just turns up that this is supposed to be a Q45 TPS...but all the service info I can track down says I should have two connectors, one a 3 pin Bosch style (idle switch) and the other a 3 pin oval on a pigtail (TPS sweep), all the eBay listings for Q45 throttle bodies also show this type of sensor. Anyone have any clues on this or know where I might be able to find out? I missed out on doing much driving this past year but I'm hoping Covid lets up this summer/fall so I wanted to get this on while the car is sleeping for winter and do some shake down this spring before going back to Tail of the Dragon or some beginner auto-cross.
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Bitter
Posts: 7
Joined: Wed Jan 13, 2021 5:21 pm
Car: Uhhhh 2000 Celica, it's....complicated.

Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Fri Jan 15, 2021 5:22 pm

Is there a different forum section or different Nissan/Infiniti forum that's more active I should ask this on?

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VStar650CL
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby VStar650CL » Fri Jan 15, 2021 7:01 pm

No, we're probably all just stumped. The manufacturer marks may or may not be identifiable, so with no Nissan p/n on the housing, you're probably SOL for an exact ID.

Bitter
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Fri Jan 15, 2021 7:22 pm

That's not the Nissan part number (A71-600 P21) on the bottom of it?

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VStar650CL
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby VStar650CL » Fri Jan 15, 2021 7:50 pm

Nope. Nissan p/n's are all xxxxx-xxxxx. That's a manufacturer's mark.

Bitter
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Fri Jan 15, 2021 8:19 pm

Boooo. I'll look more closely but yeah I don't think I saw any numbers like that. I assumed that was the part number. Thanks anyway, might be time for plan F, open it up and see what terminal connects to what.

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VStar650CL
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby VStar650CL » Fri Jan 15, 2021 9:31 pm

Three-pin TPS's are generally balance resistors (pots). Chances are the center pin is signal, with one end pin connecting to power and the other end pin connecting to ground. To confirm that, take ohm readings from center to end on both pins. Then rotate the sensor to the stop and take readings again. If resistance on one side increases after rotation and the other side decreases, then it's a plain-old potentiometer.

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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Sat Jan 16, 2021 9:11 am

VStar650CL wrote:
Fri Jan 15, 2021 9:31 pm
Three-pin TPS's are generally balance resistors (pots). Chances are the center pin is signal, with one end pin connecting to power and the other end pin connecting to ground. To confirm that, take ohm readings from center to end on both pins. Then rotate the sensor to the stop and take readings again. If resistance on one side increases after rotation and the other side decreases, then it's a plain-old potentiometer.
Alright, you're correct that the center is signal and that backs up what I thought about it already, thank you. If I label the pins from left to right with the sensor facing down as it sits in the 3rd photo then pins 1+2 sweep from 4300ohms to about 800 ohms, pins 2+3 sweep from about 700 ohms to about 4100 ohms. Pins 1+3 have a static resistance of 4700 ohms either way I probe it so I don't think there's any kind of diode inside I'll smoke. According to the intake manifold install guide I'm following in order to get everything read to install this table shows what I should be seeing between the pins of a Q45 TPS with that harness out the side of it.
Screenshot_2021-01-16 Microsoft Word - Intake Manifold Installation Guide 00-02 Celica GTS docx - IntakeManifoldInstallatio[...].png
How they laid it out is a bit confusing.

I'll try hooking up power and ground from an old PC power supply (easy 5V source) on pins 1+3 and see if the voltage on pin 2 sweeps like what my ECM is looking for, about .4 closed and about 4.6 full open which is roughly the same as a Q45 happily. If I don't get the sweep I need then I'll look for the correct sensor I guess and chock this up to a $90 learning experience to not buy things on eBay's mobile app because it makes seeing important information like the seller doesn't accept returns painfully obtuse. What's odd is that RockAuto also lists the same style sensor for a 91-94 Q45 but neither harness connector they sell for the same car fits this sensor. Someone somewhere screwed up a parts listing. https://www.rockauto.com/en/moreinfo.ph ... 2764&jsn=8

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VStar650CL
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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby VStar650CL » Sat Jan 16, 2021 9:31 am

If you find the span is okay but the top and bottom voltages are shifted low or high, you can add an external resistor to to bias it. I can help with determining the value if that's the case.

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Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Sun Jan 17, 2021 10:03 pm

VStar650CL wrote:
Sat Jan 16, 2021 9:31 am
If you find the span is okay but the top and bottom voltages are shifted low or high, you can add an external resistor to to bias it. I can help with determining the value if that's the case.
Awesome, I would completely appreciate that. I'll have some time during the week to mess with it. Manifold has been sitting for a few years and I'm only now getting around to doing this, always wary of making drastic changes to the car for fear of it making things worse not better. Just need to be more confident that I know what I'm doing, haven't gotten things wrong yet.
43674101845_8dcc02503a_k.jpg

Bitter
Posts: 7
Joined: Wed Jan 13, 2021 5:21 pm
Car: Uhhhh 2000 Celica, it's....complicated.

Re: Need help ID'ing what Nissan/Infinit this TPS came from?

Postby Bitter » Sat Jan 30, 2021 10:02 am

Ok, been a long week of being lazy (and GF had a morning shift schedule so priorities in the evenings). Got an old PC power supply, pulled two Molex round terminals out, slid them onto the two pins on the TPS, connected the Fluke to center pin on the + lead and ground on the - lead and flipped the switch on the PSU. I'm seeing an appropriate voltage at closed throttle that I can adjust by shifting the TPS to anywhere that the Celica should find acceptable and I'm also seeing a high enough voltage at full throttle that it should also work ok. I can shift the TPS on the vehicle somewhat to get it where I need it I think. I don't think I'll need any bias resistors but if I do I know who to ask!

Celica is looking for 0.3-0.8 at closed throttle and 3.2-4.9 at full throttle. I can easily hit 0.6 closed and 4.5 fully opened. I'll order a pigtail that looks like it fits and get a set of 3 pin connectors to make this plug-n-pray on the car so it's easier to swap back if I need to and do the wiring work then borrow my little scan tool from work to verify that I'm getting the correct sweep. Once again, thank you for your help with this. I probably could have eventually figured it out on my own but it's nice to have some help along the way to make things a little less stressful.


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