1993 GA 3.3 Surge at idle...
2nd1993GA
12-02-2007, 10:21 PM
My GA has an intermittent idle surge when warm. If the transmission is in any gear the idle seems fine. However when the transmission is placed in "neutral" or "park" the idle can surge from normal to almost dying, up and down at about 5 second intervals per cycle. After a minute or so the idle will sometimes become normal. The Throttle position sensor and the Idle air control have been mentioned. No codes...Any other ideas?
xeroinfinity
12-03-2007, 08:30 PM
Welcome to AF.
Sounds like a vacum leak, but you can test the TPS and IAC.
For the tps- connect a voltmeter to terminals(back probe) A and B on the TPS.
With the ignition ON and the engine running, the TPS voltage should be 0.450-1.25 volts at idle to approximately 4.5-5 volts at wide open throttle.
If the readings are not with in those perameters replace the Tps.
Testing the IAC -Attach an ohmmeter to the top two prongs of the IAC valve, terminals A and B.
Measurements should be between 50-80 ohms.
Repeat for the two lower terminals, C and D.
If the sensor reads out of spec, replace the Iac.
Hope that helps.
Sounds like a vacum leak, but you can test the TPS and IAC.
For the tps- connect a voltmeter to terminals(back probe) A and B on the TPS.
With the ignition ON and the engine running, the TPS voltage should be 0.450-1.25 volts at idle to approximately 4.5-5 volts at wide open throttle.
If the readings are not with in those perameters replace the Tps.
Testing the IAC -Attach an ohmmeter to the top two prongs of the IAC valve, terminals A and B.
Measurements should be between 50-80 ohms.
Repeat for the two lower terminals, C and D.
If the sensor reads out of spec, replace the Iac.
Hope that helps.
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