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Throttle Position Sensor (TPS)


Old 01-10-2015, 03:17 PM
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Throttle Position Sensor (TPS)

Ok guys I have a 1991 Z28 350 tpi
I've been trying to tune/adjust the tps and I was told take an ohm meter and turn to DC and to get to .540 but to adjust the sensor I have to adjust the idle and to get to that I idle at like 3000 rpm?
any suggestions.
Originally had it set at about .330

P.S. the reason I'm doing this is because when I start the engine for the first time especially when its cold I have to keep my foot on the gas enough so it doesn't just choke and die. It will also die on me when im driving. Once the car warms up its completely fine and there is no trouble.
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Old 01-11-2015, 10:58 AM
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Re: Throttle Position Sensor (TPS)

You don't adjust the sensor by adjusting the idle stop screw. You loosen the screws that hold the TPS sensor to the throttle body, and rotate the sensor until you get the correct volts. Then retighten the screws. But put the idle stop screw back where it belongs before adjusting the TPS voltage.

To accurately get the idle control back where it belongs, you have to put a scanner on the ECM, back off on the idle stop screw until RPM are at spec and the IAC counts are in the range of 20-40 counts. Then set the TPS voltage where you want it.

Make sure the throttle position sensor is indexed correctly to the throttle blade shaft.

Also, with the harness connector off the sensor, make sure you have 5.0 V across the black ground wire and the gray wire in the connector.

Last edited by Injuneer; 01-11-2015 at 11:01 AM.
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