TPS Question

[2 QK 4 U]

Is the TPS voltage supposed to be the same according to the pedal with engine off as engine on?

Engine OFF-1/4 pedal - 1.45 - 1.50

Engine ON - Park -1/4 pedal - .75 - .80

Does this sound right?

I'm using scanmaster and Direct Scan and they both give me the same readings.

Thanks,
Jason

 

[RUQWKNF]

It's supposed to be very close.
Looks like there may be an issue there.
I know mine is usually within .02v when engine running, to engine off. Typically just a little lower with engine off.
I'd look into it with a voltage swing that high. I guess the only real way to make sure you have 1/4 pedal both ways would be to insert a stop between the t-body screw and the linkage to verify the same amount of open throttle.

Patrick

 

[scottyb]

How are you "measuring" your 1/4 throttle application? I hope it's not by the feel of your foot. 1/4 throttle in park will have the engine spinning madness anyway.

Why are you concerned with checking this? Is the car not running right? Use direct scan to log a short drive and roll into the throttle evenly. Will the DS log show smooth increase in TPS, up to a proper WOT value?

 

[2 QK 4 U]

How are you "measuring" your 1/4 throttle application? I hope it's not by the feel of your foot. 1/4 throttle in park will have the engine spinning madness anyway.

Why are you concerned with checking this? Is the car not running right? Use direct scan to log a short drive and roll into the throttle evenly. Will the DS log show smooth increase in TPS, up to a proper WOT value?

1/4 is approximate but it's close... it's very aparent that there is a big difference in readings.

yes, the car is not running right. should have a lot more power.

I'll go for a test spin here shortly.

Thanks,

 

[jpratt]

Wouldn't you be more interested in idle .42 and WOT 4.6? or there abouts. Does idle level change when the car is running, if it does I bet you have a grounding issue?

 

[BlackBandit]

They should be close. (maybe a .05 or so difference) A more accurate way of checking it is to measure at idle and wot and then verify it sweeps smoothly from its lowest to highest reading. The only way I see of getting an accurate part throttle on/off measurement is to use some sort of limiting device so there is absolutely no way the tps could be in a different spot. FWIW, a difference that big between off and on can only be caused by a difference in the supplied voltage to the sensor. If it really is dropping that much then I would suspect your charging system is not working and the ignition ect. is drawing a ton of power from the battery causing the tps voltage to go down. That's why the voltage on the tps typically goes up a little when you start the car. When you're on battery the system has about 12.5 volts available. When you start the car the charging system supplies more voltage and the sensor voltages go up a little as well. HTH. james

 

[scottyb]

FWIW, I recall reading a thread many moons ago about a guy with TPS issues. His turned out to be a wiring problem where the wire unsulators wore off and shorted inside a loom or bundle.....or something like that.

 

[2 QK 4 U]

FWIW, I recall reading a thread many moons ago about a guy with TPS issues. His turned out to be a wiring problem where the wire unsulators wore off and shorted inside a loom or bundle.....or something like that.

Ok I just got back from doing a test run record w/DS....not good.

I'll post the file once I get it zipped.

 

[2 QK 4 U]

Here is the DS file....22lbs of boost