2003-04 Mach 1 Registry Owners Club - TPS voltage won't go below ~190

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- - TPS voltage won't go below ~190 (http://www.mach1registry.org/forums/showthread.php?t=136863)

HamMach1

07-17-2019 09:38 PM

TPS voltage won't go below ~190

Changed the IAC valve and the TPS today.

Removed old TPS, installed new one, started car up, held a rev at about 1800 rpm. Actually decided to research the TPS and learned it needed adjusting. Plugged in SCT, saw the TPS voltage was floating around 190 and no matter how much I rotated it (which is barely any obviously), it wouldn't change much by +/- 5.

Then I think I broke the new TPS by putting a load on it (opening the thottle body a little), thinking maybe that's how it was supposed to be done, only to basically destroy that little internal measuring doohickey once I released tension, as it now holds little tension and only read something like 1.20 lol... and maybe that little *snap* sort of noise I heard was telling. Put old TPS back on, still read around the 190 or so.

Could it be something with the throttle body? Could the SCT be that far off?

Oops, this is the mentioned doohickey:

https://i.imgur.com/x2K2EYS.png

hotford

07-18-2019 12:51 AM

Re: TPS voltage won't go below ~190

Voltage at idle should be close to 1.0 Volts

HamMach1

07-18-2019 10:52 AM

Re: TPS voltage won't go below ~190

Quote:

Originally Posted by hotford (Post 1634615)

Voltage at idle should be close to 1.0 Volts

I'll have to try again today. Maybe I read the scanner wrong. I'll snap some photos.

HamMach1

07-18-2019 06:40 PM

Re: TPS voltage won't go below ~190

Something tells me this isn't good lol. This is the old one. The new one flashes back and forth between 1.00 and .75, so I think it's busted, as I don't think it's actually getting a read at all. I found a Motorcraft TPS online that I'm going to try in a few days. My RPM still stuck at about 1800 RPM and was rising so it's all sorts of messed up.

https://i.imgur.com/LxuQ6hQ.png

bigtrain

07-20-2019 08:38 AM

Re: TPS voltage won't go below ~190

Is it a oem throttle body

HamMach1

07-24-2019 07:05 PM

Re: TPS voltage won't go below ~190

Quote:

Originally Posted by bigtrain (Post 1634634)

Is it a oem throttle body

Yep. Tried a second TPS. Throttle reads 1 and then flashes .75 and back to 1 and back to .75, whether the TPS is plugged in or not.

Possible wiring? No idea how I could have ruined everything just by replacing the IAC and TPS lol

rich1

07-27-2019 02:18 PM

Re: TPS voltage won't go below ~190

This sounds like a bad ground in the wiring . Check engine and PCM wiring harness for proper grounding. Use wiring Diagram for Pinpoint check on PCM outlet plug to see if 1.0 volt is present

HamMach1

07-28-2019 07:37 PM

Re: TPS voltage won't go below ~190

Quote:

Originally Posted by rich1 (Post 1634668)

This sounds like a bad ground in the wiring . Check engine and PCM wiring harness for proper grounding. Use wiring Diagram for Pinpoint check on PCM outlet plug to see if 1.0 volt is present

Thanks Rich. I'll look into that

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