WOT Switch Questions
12-26-2009, 01:18 PM
#1
Racer
Thread Starter
WOT Switch Questions
Okay, I think my WOT switch is dead. I tested the terminals at both the LH and EZK connectors and no reaction when the throttle is pressed.
Next question...what does this mean?
DO I need to get a new switch? When they fail is it generally a connector problem or a switch problem? Is there anythin else I can try to fix before pulling the top end?
Next question...what does this mean?
DO I need to get a new switch? When they fail is it generally a connector problem or a switch problem? Is there anythin else I can try to fix before pulling the top end?
12-26-2009, 01:58 PM
#2
Rennlist Member
make sure you are testing the terminals correctly. see if your idle switch is working too.
If they both are not working, maybe its the connection to the switch unit.
If they both are not working, maybe its the connection to the switch unit.
12-26-2009, 02:03 PM
#3
Racer
Thread Starter
Idle Switch is working
I tested the Idle switch at the same time and it is working well. I check the WOT and Idle on the EZK and LH wiring connectors.
12-26-2009, 02:44 PM
#5
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It means that, after you've checked your throttle cable as Wally suggests and after you've triple-checked your WOT test as mK suggests, you will need to begin studying the various guides for intake R&R.
Failure of the WOT part of the switch is as common as dirt.
On the other hand, if the WOT part of the switch is the only thing wrong in the vicinity of the intake, and if your 928 is primarily a street car and you don't spend lots of time at full-throttle then you can leave it be for a while.
Failure of the WOT part of the switch is as common as dirt.
On the other hand, if the WOT part of the switch is the only thing wrong in the vicinity of the intake, and if your 928 is primarily a street car and you don't spend lots of time at full-throttle then you can leave it be for a while.
12-26-2009, 03:17 PM
#6
Drifting
The adjustment of the throttle cable only affects the idle speed if cable is too tight. The cable adjustment should not affect the idle enrichment, unless the throttle position switch (TPS) is miss adjusted.
The TPS position is adjusted for idle switch only. The TPS full throttle switch-on position is not critical for full throttle enrichment.
The TPS position is adjusted for idle switch only. The TPS full throttle switch-on position is not critical for full throttle enrichment.
12-26-2009, 03:31 PM
#7
Racer
Thread Starter
WOT Symptoms
Actually the reason I was checking the WOT throttle switch was because the car runs rich and surges in IDLE. I have a Air fuel gauge on the car and it was reading pegged rich so I assumed that the MAP was stuck. This is what lead me to the WOT
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12-27-2009, 06:08 AM
#8
Rennlist Member
You rich condition could be due to
1) faulty O2 sensor
2) LH early signs of failure, they can "think" you are at WOT when in fact you are not.
3) MAF failure
4) Ruptured FPR on damper diaphrams
For 1) try unplugging the O2 sensor, when battery ground is disconnected, then reconnect and run the car.
For 2) try LH swap with known good unit
For 3) Try to measure MAF volts at LH at idle, should be around 2.7v
For 4) remove vac line to front damper and check for fuel.
1) faulty O2 sensor
2) LH early signs of failure, they can "think" you are at WOT when in fact you are not.
3) MAF failure
4) Ruptured FPR on damper diaphrams
For 1) try unplugging the O2 sensor, when battery ground is disconnected, then reconnect and run the car.
For 2) try LH swap with known good unit
For 3) Try to measure MAF volts at LH at idle, should be around 2.7v
For 4) remove vac line to front damper and check for fuel.
12-27-2009, 10:20 AM
#10
Racer
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Wise words John.
You rich condition could be due to
1) faulty O2 sensor
2) LH early signs of failure, they can "think" you are at WOT when in fact you are not.
3) MAF failure
4) Ruptured FPR on damper diaphrams
For 1) try unplugging the O2 sensor, when battery ground is disconnected, then reconnect and run the car.
For 2) try LH swap with known good unit
For 3) Try to measure MAF volts at LH at idle, should be around 2.7v
For 4) remove vac line to front damper and check for fuel.
1) faulty O2 sensor
2) LH early signs of failure, they can "think" you are at WOT when in fact you are not.
3) MAF failure
4) Ruptured FPR on damper diaphrams
For 1) try unplugging the O2 sensor, when battery ground is disconnected, then reconnect and run the car.
For 2) try LH swap with known good unit
For 3) Try to measure MAF volts at LH at idle, should be around 2.7v
For 4) remove vac line to front damper and check for fuel.
12-27-2009, 06:15 PM
#11
Rennlist Member
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We have seen throttle cables so loose that the throttle simply wasn't opened enough to operate the WOT switch...
That will not cause your over-rich problem in any case. The only way that the WOT switch could be involved would be if it has failed in the closed position, which is not too likely.
My only addition to John's post is to suggest that you check the vacuum lines for traces of fuel on all three units - two dampers, one regulator.
That will not cause your over-rich problem in any case. The only way that the WOT switch could be involved would be if it has failed in the closed position, which is not too likely.
My only addition to John's post is to suggest that you check the vacuum lines for traces of fuel on all three units - two dampers, one regulator.
12-27-2009, 11:29 PM
#12
Race Car
When you checked your idle and Wot at the LH was the idle pins shorted and Wot pins open with pedal not depressed, when pedal is pushed fully was the idle open and the Wot not shorted. If so then the switch is bad or out of adjustment. If you can get at the TB you can look for the Wot opening at 2/3 travel of the pedal and check the switch connections at the TB. If you have a large vacuum leak such as on the Maf to TB seal you will run rich.
