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Aug 22, 2004 | 09:22 PM

ewellman

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TPS question

Today I was checking the voltage of my TPS. Checked reference - 5 v(top wire -black and bottom wire) when I probed the top and middle wires I got a reading of 4 v and decreased to below 1v when I opened the throttle. Is there something wrong with the sensor or me? I did the procedure as I have read on other posts and in the manual. KOEO

The reason I was checking this is, when I am under the hood with the engine running and push the throttle there is a slight hesitation almost acts like it wants to die, just for a second, before it revs up.

Aug 24, 2004 | 01:06 PM

87 XLT

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From: SoCal

Simplest way to test for a bad TPS is to pull the codes. The TPS should smoothly go from approx 1 volt at idle to approx 5 volts at full throttle. Move the throttle slowly as you watch the voltage, any jumping around of the voltage means the TPS needs replaced.

Aug 24, 2004 | 01:31 PM

87 XLT

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From: SoCal

Aug 24, 2004 | 05:35 PM

ewellman

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Thanks for the reply. I was more curious as to why when I did the test the voltage was reversed. It started at 4-5v at idle and dropped to below 1v when I opened the throttle. I am not sure if there is some thing wrong with the TPS or the way I tested. This is puzzeling. I hope some one out there will have some idea as to why this is happening. Is there the possibility of wires being reversed?

Aug 24, 2004 | 05:40 PM

87 XLT

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From: SoCal

If I remember correctly the "signal" wire is the center wire & you need to test between there (shove a sewing needle thru it)and any ground. But take a look at the "technical information sticky" at the top of the Ranger forum & click on "TPS testing"

Aug 24, 2004 | 06:19 PM

ewellman

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OK I just went out and did the test again. Top wire is the black wire. Bottom 2 wires not sure of the color because of fading. Black wire to bottom wire (reference) -5v. Top wire to middle wire - (at idle) - 4-5v and as I open the throttle moves smoothly to -1v. If I use the red lead (volt meter) on the black wire the voltage switches from neg to pos. But still starts at 4-5v at idle and drops to 1 or less v as I open the throttle. I am still puzzled.

Aug 24, 2004 | 07:07 PM

ewellman

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I just got done testing the resistance. I disconected the harness from the TPS and checked the ohms. At idle 3.12 ohms (good) then when I opened the throttle instead of increasing to 350 ohms (open resistance) it dropped (gained resistance) to 1 or so ohms. Any body????