bmw88rider (Forum Supporter)
bmw88rider (Forum Supporter) GRM+ Memberand UltraDork
7/11/20 10:22 a.m.

So I am trying to do a first start on a 94 miata that I removed the old Link system on and installed a mspnp2 release 3.4.3 on. It's currently NA with a header, exhaust, and CAI on it. It's running a GM IAT on it plumbed in just before the Throttle Body.


When I boot up tuner studio, It's reading 1017 both open and closed. I replaced the original TPS with a known good one and same result. I know when I did the Link removal, I replaced the patched wiring harness leading into the ECU with a non cut up OEM junk yard replacement. My next step is checking out the continuity from the connection to the ECU. Any other ideas to check? I looked at the Throttle Body and it is moving properly. 


Any Ideas? I'm stumped here.  

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
7/11/20 10:25 a.m.

Bad signal wire, bad ground, signal going to wrong pin. Those are the only things I can think of.

bgkast (Forum Supporter)
bgkast (Forum Supporter) GRM+ Memberand PowerDork
7/11/20 11:07 a.m.

I agree with Angry'vare. Check your ground and power to the sensor, and make sure you have the wires connected to the correct pins. I just finished a Megasquirt install and had my tps pinout incorrect giving a backwards reading.

Honsch New Reader
7/11/20 11:08 a.m.

It's the ground wire.

Assuming they use a 10 bit A/D converter a full-scale reading is 1023.

The ground side of the TPS is floating.

bmw88rider (Forum Supporter)
bmw88rider (Forum Supporter) GRM+ Memberand UltraDork
7/11/20 4:35 p.m.

Thanks guys. Sounds like I need to run through the sensor grounding circuit. I was getting some interesting information from the engine temp sensor as well. It was not giving a consistent reading. I imagine it is related. 

MadScientistMatt PowerDork
7/14/20 12:32 p.m.
pleura said:

Hello folks so I have a 1994 Miata undercarriage with a NB motor. I am attempting to align the TPS with the 94-95 mspnpv2 and it is perusing excessively high (1023). I have a 99/00 skunk2 choke body and I am utilizing a NB tps (I accept the 94 TPS tackle won't plug into the NB tps?)

This also sounds like a sensor ground issue; you'll need to make sure it's pinned out correctly.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) Dork
7/14/20 1:16 p.m.

Unplug the TPS and start looking for 5v on the TPSvREF wire as well as check the pin for signal ground back to the ECU. You should see low adc if you manually jumper signal and signal ground, and high adc when you jump 5v to signal. If that checks out than verify the tps pinout.

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