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Thread: TPS Sensor

  1. #1

    Default TPS Sensor

    While doing a remote tune session with Rich/Fastman we discovered that my TPS would show 1-4% when I wasn't doing anything to it. At first I thought it was just the throttle stop screw was loose, so I put a stop nut on it and that seemed to tighten it up. I say it seemed like it did because then the next time the engine was hot it again showed 1-2% when I wasn't touching it, and a couple of technical taps on the sensor made it really jump around to show that it was bad. While going to the parts store that night for the new TPS it occurred to me that maybe it was the harness on it that was getting loose when it was hot and causing a problem. The store had the TPS, but had to transfer the harness in so I took the sensor home and had them send the harness in the next day. I replaced the sensor, got the car warmed up and again noticed it was rising with no change to the throttle. With the engine warm this time I played with the TPS harness and realized it was old and loose when it was hot, so I picked up the harness and soldered it on the next day.

    Well I guess that fixed the problem as it doesn't rise when the engine is hot, but now after I first start it the TPS will show 1% a few times until it gets up to temp and then it stops changing. I did a TPS Autoset after each of the change I made, replacing the sensor or the harness, and today just because I noticed the slight change. What am I doing wrong now?

  2. #2
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    Default

    Replace the TPS sensor if you haven't already done so, and check the wiring.
    http://forums.holley.com/showthread....=2760#post2760 (Replacement Sensors For Holley EFI - Auto Parts Store)
    http://forums.holley.com/showthread....0422#post10422 (TPS Wiring, Autoset Error/Troubleshooting)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. #3

    Default

    After doing a TPS Autoset, try backing the throttle stop screw out just a bit.
    '95 Lightning, HP EFI, 351W, S472SX-E, 20 PSI,N2O,pump & W/M

  4. #4
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    Read 3rd paragraph: http://forums.holley.com/showthread....neral-IAC-Info (General IAC Information - Read "IAC NOTES")
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #5

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    I've already replaced the TPS and the harness going to it. It's on a Ford 302, stock TPS sensor, not sure if there's a different/better one to use? At this point the sensor and harness seem solid in that messing with the harness or technical taps on the sensor do now show any changes. I'll try backing it out just a hair to see what happens. It's strange as it only does it when its cold now and it only shows 1% for a split second at a time for the first few minutes until it's up to temp. Once it's up to temp it does not do it anymore.

    Not sure if it's related. I'm also having issues getting the throttle stop screw in the right position to get the IAC Position in the 5-10% range at hot idle. I had it setup nice at 10% the other day and now last night with no changes is was at 35% at hot idle. I again adjusted the throttle stop screw, did the TPS dance and cycled the ignition and got it back down last night. But part of me knows today when I start it, the IAC Position will be down to 0%. I've done this a couple of times now, and again, I'm not sure what I'm doing wrong. Thanks for your time in answering.

  6. #6
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    Quote Originally Posted by ttocs View Post
    It's strange as it only does it when its cold now and it only shows 1% for a split second at a time for the first few minutes until it's up to temp. Once it's up to temp it does not do it anymore.
    I wouldn't be concerned about this. The IAC Hold Position is activated at 2% TPS Position for 0% idle return issues.
    http://forums.holley.com/showthread....ents-Read-This (Initial Checks & Adjustments - Read Steps #1-#6!)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS TW 11R 205 heads, 11.8:1 comp, TFS R-Series intake, Dominator MPFI & DIS, 36-1 crank trigger/1x cam sync, 160A 3G alternator, Optima Red battery, A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/off-road X-pipe/shorty headers, S&W subframe connectors, LenTech Strip Terminator wide-ratio AOD/2800 RPM converter, M4602G aluminum driveshaft, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  7. #7

    Default

    OK well that's a relief then, as I was not sure what else to check.

    Any advice on what could be leading to me chasing the the throttle stop/IAC? The Ambient temp and humidity was a little different, but I don't understand why the IAC would change so much without changing anything else.

  8. #8

    Default

    Ford IAC valve?
    '95 Lightning, HP EFI, 351W, S472SX-E, 20 PSI,N2O,pump & W/M

  9. #9

    Default

    I swapped out the IAC to the LSx based with the Accufab adapter.

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