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Discussion Starter #1
does the throttle position sensor have to be electronically set for the car to idle correctly or not? its for an 89 camaro. the TPS is new but i just put it in and ajusted it some.
 

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Yes, TPS has to be manually adjusted for .480-.500 volts from the center terminal and one of the other terminals. You can adjust it with engine running or not, IGN on.

I found it made a good difference adjusting by ear to listen to the engine idle. Ended up with .550 volts. Full throttle position, engine off, key on, gave 4.80 volts.

Hope this helps.
 

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Discussion Starter #3
thanks 4 the help. what is it i need to use to do this? or who can i go to and what will they charge?
 

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You can use a DMM (digital multimeter) and back probe the connector onto the TPS. Or, have a shop plug in their handheld machine into the ALDL connector under the dash and read the voltage setting directly from the data line to the ECM. Probably wouldn't cost much, most local shops have this capability.

After setting the TPS for the correct amount, disconnect the battery for a couple minutes to remove the trouble code for either setting it too low or too high.
 

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If that is a TPI motor, it's a good idea to start from the RPM adjustment first. I posted something in the engine archive (perhaps) on the procedure. It involves putting the EMC into diag mode, turning the key off and disconecting the IAC motor. This will put the IAC motor at known setting. Then the idle curb screw is adjusted to spec (it's in the manual - I'd hate to guess). Then reconnect the IAC motor and remove the ECM from diagnostic mode. Afterward you can do the TPS adjustment.
 

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Discussion Starter #6
oh ok. I was reading up on this a little and the book sugested using a voltmeter grounding the A & B terminals at the TPS and setting the voltage at that point with the ign in on position. is this the same thing your talking about with the DMM?
 

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Originally posted by j-micc:
... grounding the A & B terminals at the TPS and setting the voltage at that point with the ign in on position. ....
I don't think you want to ground anything. I suspect you would connect your meter leads to the A& B terminals. Grounding any of those pins can damage the computer or the sensor.
 

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Thank you dnult for verifying. Yes, one should measure across those two pins, not each pin to ground nor ground each pin.

Good thing there are others here to check and wake up others.......
 

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Discussion Starter #10
sorry didnt mean 2 use the word ground. I tried the proccedure with the DMM and it will not gie me a reading at the voltage part of the DMM. the manual says to to use the 20k ohms part of the meter. If this is so, what should be the reading at that end? or am i confused?
 

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If using the OHMS scale, you're trying to see if there are any open spots in the TPS while slowly rotating from idle to wide open throttle. This step is done with the ign key off.

Then, after finding no holes, as you've stated you 've replaced the TPS, place DMM to DC volts and probe the same terminals for voltage with ign key ON, and adjust accordingly. Tighten screws of TPS.

Follow Dave's instruction and set base idle, no ECM control, first, then, set TPS. Read the technical manual.
 
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