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1988 RX-7 TPS "hardwired"???

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Old Feb 18, 2017 | 08:17 PM
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1988 RX-7 TPS "hardwired"???

Hello, I recently purchased a 1988 rx-7 na, the throttle position sensor is not connected at all, the car idles rough, and will drive but cuts out around 4K rpms which I understand can be grounds, however the tps is not connected, where there once were three wires going to the standard plug, those three wires come to quick connects that I assume were a "get-by" fix at one point, however are attached to nothing now, I could buy a new tps, but I don't see the original plug it's supposed to connect to, my question is why would someone do this, and what is my best rout of fixing the issue, thank you
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Old Feb 18, 2017 | 09:21 PM
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The best option is obviously to replace the connector. I searched a bit online but couldn't find the right one for you.

If I were in your position, I would first look at local wrecking yards. If they have a 7 in the lot (which is unlikely at best) and it is from years 86-88, it should have the connector you need (although the yard may not want to sell you the connector alone as you will have to cut it from the harness).

If you don't find a 7 nearby with the connector you need, then your next best choice would be to just buy a generic three pin connector on eBay or at your local electronics store and splice one end onto the three wires from the harness and the other end onto the wires of the TPS. Make sure to use dielectric grease and heat shrink to prevent corrosion.

Your last resort would be to connect your new TPS to three quick connects and connect them to your existing harness. Once again, use dielectric grease and heat shrink.

Just my $.02
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Old Feb 18, 2017 | 10:54 PM
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the factory sensor sucks, probably got tired of replacing it and just yanked it while trying to find another.


i keep forgetting to try finding a workaround for this with another sensor. $200 for a stock TPS prone to failure is a bit out there. it's just a bit of a pain as i dont have any stock cars to guinea pig anymore.
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Old Feb 19, 2017 | 09:30 AM
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The Green/Red wire of the TPS pigtail runs to pin 2G of the ECU. The Black wire is a ground that initially came from pin 2E. And the remaining Brown/White wire comes from pin 2A.
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Old Feb 19, 2017 | 10:13 AM
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Thanks guys

Calling around to scrapyards today, chances of finding one the correct years and an rx7 alone is nearly impossible I'm finding out, most like will pull the three wires I need out of the harness and connect them as I have, but I still have no idea if the tps on the car is good, otherwise I don't know why it would've been messed with in the first place, thanks for your help and if worst comes to worst I'll use the same quick connects with dielectric grease, thanks guys I really dont want to drop 200+ for a sensor that may or may not be the issue, so I'll start simple, thanks again
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Old Feb 19, 2017 | 10:17 AM
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There is an ohm test to check the TPS plus a voltage test as well.
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Old Feb 19, 2017 | 10:28 AM
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Tps

These are the existing tps wires with quick connects, which I assume were hard wired into the harness, why would someone want to bypass the original connection?
Problem being I can't check the circuit if there's no circuit, so I would have to replace the circuit before testing it correct? Or can I read it directly from the existing tps wires?
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Old Feb 19, 2017 | 11:04 AM
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The ohm test does not require a circuit as the test is done with no key in the ignition and the test uses the wires coming from the TPS.
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Old Feb 20, 2017 | 11:39 PM
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Originally Posted by 1988 rx-7
These are the existing tps wires with quick connects, which I assume were hard wired into the harness, why would someone want to bypass the original connection?
Simple answer is: it's easier for a lazy, ignorant, and/or mentally handicapped person to snip wires and crimp connect the sensor to the harness rather than to fix the corroded connection the factory spade connector likely had using a new connector, solder, and heat shrink.

I prefer to eliminate the factory 3 spade connector and its related corrosion in favor of a GM 3 wire weather proof connector, found on almost any mid/late 90's and up GM car at the junk yard. I simply cut out the 3 spade connector and solder in the GM connecter, heatshrink the connections, done.

Why? Because that connector is right next to a coolant filler cap. Coolant + non-waterproof connector = corroded connection. I've never seen a factory TPS without excessive corrosion on the factory connector. Eliminating the corrosion associated with the factory connector helps a lot when the TPS actually goes bad because you can be sure testing it at the ECU that you're not just getting false readings from a poor connection at the connector.
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Old Feb 21, 2017 | 12:03 AM
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some of us hate accessing the ECU for such menial and easy tests, i've only checked my ECU about 3-4 times and my carpet pad has yellow nibbles left all over that passenger floorboard from that stupid cover. i hate the ECU location.. don't ask me why i put my microtech there, except it has a serial cable!

i'll stab a wire before going through that much hassle.

Last edited by RotaryEvolution; Feb 21, 2017 at 12:06 AM.
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Old Apr 1, 2017 | 09:55 AM
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What are options to get rid of the stock POS TPS? I have an Rtek 1.0 on my91 NA...
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Old Apr 1, 2017 | 10:06 AM
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a real standalone is the only way, otherwise i am working on a replacement still.
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Old Apr 1, 2017 | 10:47 AM
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Originally Posted by RotaryEvolution
a real standalone is the only way, otherwise i am working on a replacement still.
doing god's work
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Old Apr 1, 2017 | 09:08 PM
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lol, seems that way. there's a reason why no one has come up with one yet.
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