Robb235

Hi guys,

I hooked up my OBD II scanner the other day to my new-to-me '97 4Runner Limited with the 3.4 to check the readings of the engine's sensors. With the engine off and ignition on, I noticed that the TPS was registering a value of 11.8% with my foot completely off the gas. When I depressed the gas pedal all the way, it registered 76.5%. I opened the throttle body all the way by hand and it still returned a value of 76.5%. This doesn't seem right to me; do I need a new TPS?

waskillywabbit

iTrader: (-1)

And how does that compare to acceptable stated readings in the FSM?

:wabbit2:

Robb235

I currently do not have a FSM for this vehicle, so I do not know.

J2F42C

With my scangauge ii, it reads 10 at 700 RPMs.

Are you getting a code indicating that the TPS is problematic? If not, don't sweat it.

If you want to check it though:

http://www.ncttora.com/fsm/

TheDurk

GOOD QUESTION!!


Per my '99 FSM, p. DI-169:
Throttle valve fully closed: 7-11%
Throttle valve fully open: 65-75%.

You are high on both by a smidgin. The FSM goes on to say:

...sounds like you're good. This is a GREAT page and I had never seen it before. I'll post a link if I can find it on line.

EDIT: See page DI-11 here: http://www.ncttora.com/fsm/1996/SIL/...zfe/preche.pdf

Note: All these specs are the same in '99, except that there are no #2 fuel trim items in '99.

Robb235

Hmmmm... I don't really understand why it would be "normal" for the TPS to register a value ~25% less than what the driver is asking for. But if that's the way it's supposed to be then I won't worry about it.

TheDurk

Beats me, too. That TPS is used on other engines as well so maybe one of those has different geometry that allows for a wider angle of arc on the butterfly. It's also more precise to keep a resistance type sender a bit within its extreme range. But I'm sure the ECM is designed so that it regards anything 65%+ as WOT. In any case, the butterfly is what counts as far as volume of fuel/air mixture, the TPS just affects fuel trim and ignition timing. Those probably hit their extreme values somewhere before WOT, like maybe 50%+ (just going by how old-time mechanical distributor advances work).

Jay204

So strange to see TPS issues, all of a sudden at the same time mine is having issues. I've changed my TPS and I still get no acceralation..wish mine would get resolved i'm not enjoying my Runner right now. 235k and this is the only thing to ever go wrong.

98_3RZ

your tps will never read 100% or 0% because it uses those values for diagnostic purposes. and it associates those percentages with voltages, so if it sees a certain voltage(percentage), the ecm knows that there is a problem