TPS testing and the Haynes Manual
06-16-2003, 10:22 AM
#1
Burning Brakes
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TPS testing and the Haynes Manual
In the Haynes Manual, at the beginning of the section that describes testing the TPS it mentions that the ohmmeter should move as soon as the throttle is opened. Does this apply to all the tests that follow???
When I test between the middle (ground) and the #2 terminal, it performs per the specs - closed throttle = 0 ohms; as SOON as I open the throttle (little click is heard) the meter jumps to infinity. The test between the middle and terminal #3 is supposed to produce the opposite results. I get infinity with the throttle closed; but it doesn't go to 0 ohms until the throttle is opened about 3/4 full. Should it go to infinity as soon as the "click" is heard??? Has anybody else done these tests? I tried adjusting the TPS but the test results are the same.
My symptoms are these - hesitation at exactly 3400-3600 RPM when at low throttle (heavier throttle is smooth all the way through) and WOT is not as powerful as 90% throttle. I've had both problems since I bought the car and I've slowly been replacing/testing the ignition components to no avail.
Thank you,
Dale.
When I test between the middle (ground) and the #2 terminal, it performs per the specs - closed throttle = 0 ohms; as SOON as I open the throttle (little click is heard) the meter jumps to infinity. The test between the middle and terminal #3 is supposed to produce the opposite results. I get infinity with the throttle closed; but it doesn't go to 0 ohms until the throttle is opened about 3/4 full. Should it go to infinity as soon as the "click" is heard??? Has anybody else done these tests? I tried adjusting the TPS but the test results are the same.
My symptoms are these - hesitation at exactly 3400-3600 RPM when at low throttle (heavier throttle is smooth all the way through) and WOT is not as powerful as 90% throttle. I've had both problems since I bought the car and I've slowly been replacing/testing the ignition components to no avail.
Thank you,
Dale.
06-16-2003, 11:11 AM
#2
Three Wheelin'
Dale:
What you are seeing is normal. There are two seperate switches in the TPS housing. The "Throttle Closed" switch is a micro-switch and it clicks when it opens or closes. The Wide Open Throttle (WOT) switch is a leaf style switch.
There is a "dead band" between these switches that represents "part throttle."
During normal driving, the DME uses engine load, O2 sensor output, and data from the fuel and ignition maps to determine the injector duty cycle to maintain the proper fuel/air mixture.
At engine RPMs above 3600, or if the WOT switch is closed, the DME discards the map data and goes to a "full rich" duty cycle for the injectors.
What you are seeing is normal. There are two seperate switches in the TPS housing. The "Throttle Closed" switch is a micro-switch and it clicks when it opens or closes. The Wide Open Throttle (WOT) switch is a leaf style switch.
There is a "dead band" between these switches that represents "part throttle."
During normal driving, the DME uses engine load, O2 sensor output, and data from the fuel and ignition maps to determine the injector duty cycle to maintain the proper fuel/air mixture.
At engine RPMs above 3600, or if the WOT switch is closed, the DME discards the map data and goes to a "full rich" duty cycle for the injectors.
06-16-2003, 12:30 PM
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Burning Brakes
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Mr. Hipsher, thanks - it sounds like you really know your TPS! Because I am generally ignorant, I would like to clarify. Are you saying my hesitation from 3400-3600 AND my WOT symptoms are normal? Or just the 3400-3600 symptoms. I really appreciate your help. If my WOT symptom is normal, is there anything I can do to change it? It's really annoying looking for that 'sweet spot' when I'm trying to speed up quickly. I'd rather just stomp and go.
Dale.
Dale.
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06-16-2003, 04:32 PM
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I just went through this on my 83. The voltage test didn't quite pass as the Haynes book described it. I pretty much got the same results as you did. I opened the TPS up and it was full of oil! I replaced it, problem solved. BTW; they are around $40, but still cheap enough...
06-16-2003, 04:45 PM
#9
Burning Brakes
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Joel:
<strong>BTW; they are around $40, but still cheap enough...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hmmm, prices seem to have gone up since I did mine. Still though, it sounds like it could be a part of the problem and is relatively cheap.
<strong>BTW; they are around $40, but still cheap enough...</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Hmmm, prices seem to have gone up since I did mine. Still though, it sounds like it could be a part of the problem and is relatively cheap.
06-17-2003, 12:07 PM
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Burning Brakes
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Robert D:
<strong>When you buy a new TPS, does it come set to some sort of spec seting already or do you have to set it?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I would assume you just put it on, turn counterclockwise until it hits the internal stop, then tighten the screws.
Anybody know for sure?
<strong>When you buy a new TPS, does it come set to some sort of spec seting already or do you have to set it?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I would assume you just put it on, turn counterclockwise until it hits the internal stop, then tighten the screws.
Anybody know for sure?
