Technical Question about TPS

carpoof

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This might be kind of technical, but I would love some input. I have a 2000 Lincoln LS V8. I also have a CarChip EX data logger that reads inputs from the computer as you drive. I was monitoring Vehicle Speed, Throttle Position, Intake Air Temperature, and long term fuel trims. I noticed that when I would floor the car, it would only read about 93% throttle position. Today I took it out on a 2 minute drive where I idled for about 1 minute, then gradually accelerated to the floor, and gradually let off twice. Then I punched it and let off a couple of times too. I looked at the graphs. While idling, throttle position was a steady 18%. When I gradually floored it, it only got up to about 25%, leveled for a second or two, than jumped kind of jagged to about 30% maximum when I had it to the floor. The second time I gradually floored it and let off, the reading did go pretty steadily up to 75% and steadily back down, but it never got above 75% with it floored. When I punched it and let off about three times quickly in a row, the TPS stayed at 18% (Granted it only logs data every 5 seconds, I was doing this for more than 5 seconds) I have no driveablity problems other than lower gas mileage than expected on the highway. I have also noted with the car chip that the computer stays in open loop when it is floored, I thought it should go to closed fuel enrichment mode, but I don't know. So my question is, do you think the TPS is bad, or are those readings pretty normal. Any input is appreciated. :L :tmi:
 
I don't have any experience with the CarChip - but my ODBII tool does read my TPS going to 100% - so I don't think a lower reading would be normal.

I do believe the car goes in and stays in open loop while at WOT, which make me think you TPS is working and going to 100%, the CarChip just isn't reading it that way or some reason.
 
Thanks for the response, I am sorry I got it backwards, the computer is staying in closed mode (reading from the sensors) when at WOT. I think I will go test drive another LS from a car lot today and plug my carchip into and see what the results are there and compare them.
 
Quik LS said:
I don't have any experience with the CarChip - but my ODBII tool does read my TPS going to 100% - so I don't think a lower reading would be normal.

I do believe the car goes in and stays in open loop while at WOT, which make me think you TPS is working and going to 100%, the CarChip just isn't reading it that way or some reason.


I have observed the same response from mine and you are correct about the open loop in WOT.
 
Yea....5 seconds between samples is a LONG time. I would suspect that first. If you have another car to plug into, that is great though.
 
luckieleo said:
:soapbox: "Let me TELL YOU SOMETHING about TPS Reports...... " :N


Sounds like someone has a case of the Mondays!

I want that cover sheet on em' next time and would someone please explain what the PC load letter error means!
 
you can adjust the tps in order to reach a true 100% trim if that was actually the problem

the only thing is...adjust it too far and you're going to have some idle and transition issues
 
Thanks for your help guys, I am not going to worry about it for now, but when I get properly motivated, I will check into getting the TPS adjusted.
 
If it works KOEO properly, but not KOER its either the scanner is accessing the wrong memory address, or you're having problems with VREF somewhere....

But, if the check engine light is not on, you probably don't have a problem. There is a good chuck of code that checks TPS position vs MAF voltage, and if they don't coincide, check engine light comes on.
 

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