Author Topic: check TPS for proper op?  (Read 1922 times)

erupert66

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check TPS for proper op?
« on: January 21, 2013, 10:56:12 AM »
Chasing an idle hunt in my son's car.  We've got the heated intake bypass done and all the hoses are good.  intake gasket (upper) is new and the lower hasn't been off. Haven't found any response to spraying cleaner around the brake booster and other connections.  It's idling nice when cold.  I have another O2 sensor but haven't put that in yet.  The only code is for that, of course.  I have a spare throttle body with a TPS but that one is also unknown.  A buddy told me to measure it and ensure that it's telling the ECU that it's in the idle circuit.  It's a 3 pin setup, is there a spec for measuring resistance across the pins?

Also changing out the injectors for the Mustang ones today.  I know that I shouldn't do it until the idle is solved (in case they cause another issue) but the ones in the motor are crusty and are likely original.  It was a real bitch getting them to pop out of the head.  

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keflaman

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check TPS for proper op?
« Reply #1 on: January 21, 2013, 07:26:29 PM »
From the E30 BMW factory manual:

Operate throttle valve and observe the voltage value:
Approximately 0.6 (idle speed) and 4.2 (full load) volts. (4.9V = break)

Resistance measured at 23 +/- 5*C (73 +/- 9*F):
Idle speed position 4 +/- 0.8 k-ohms
Full load position    1 +/- 0.2 k-ohms


Here's a good thread from 'monty23psk' on reading the TPS:
https://m42club.com/forums/showthread.php?t=16521