The AUSubaru.com.au Forums

G'day all.

After reading a thread on offroadsubarus.com about the TPS and engine behaviour I thought I'd check mine out.

Most of it turned out ok - except the voltage reading. At closed throttle there should be little (0.1v) to no voltage, at full throttle there should be 5v or just under, inbetween closed and open should be in that 0v-5v range.

My TPS has this voltage range upside down. So I thought I would grab a spare I had in the shed to compare. Its doing the same thing. I don't have a code being thrown by the ECU, that said I haven't tried the diagnostic connectors to see if there's a stored code (lazy and didn't think about it before this thread).

What my EJ is doing - at low to medium engine speed the throttle is really jerky unless you're ultra sensitive in using it. It's not smooth like you'd expect it to be between no throttle and a little bit of throttle.

I was wonder what are other's experiences with their TPS and if someone can back probe their TPS to see what its doing. I find it odd that two TPSs have the same 'problem'. Other than that it drives fine...

Cheers

Bennie

And you ditched the L Series for reliability, and got yourself an EJ with a little problem - just to keep you in here and your mind active

Wonder if your source is [a] wrong, like got it backwards
or different north to south hemispheres??

There a few variations of TPS's so i doubt there is a problem if yours is backwards.

Were you using a digital or analogue multimeter?

With an analogue meter, you will see if there are dead spots in the resistor track, the needle will fall to ∞ and then back to the proper reading if there is a bad spot.

steptoe wrote:And you ditched the L Series for reliability, and got yourself an EJ with a little problem - just to keep you in here and your mind active

You don't want to get me started on my EA's reliabilities! I'll just mention the little "heart starter" it needed each morning in the hope that it would start to get me somewhere I needed to go...

steptoe wrote: Wonder if your source is [a] wrong, like got it backwards
or different north to south hemispheres??

a) apparently not - the haynes manual states the way I've said above closed = 0v, full open = 5v Other's have said the same from their manuals in reference.

b) classic!

Suparoo wrote:There a few variations of TPS's so i doubt there is a problem if yours is backwards.

Were you using a digital or analogue multimeter?

With an analogue meter, you will see if there are dead spots in the resistor track, the needle will fall to ∞ and then back to the proper reading if there is a bad spot.

If the manual says that its meant to be 0v at closed and 5v at full open, why wouldn't it also mention the difference in other TPS units?

I've got a digital that I back probed the votage readings. The resistance was tested on the digi too but can do it with an analogue that dad's got.

Frog, if you read this, could you pls quote me for a new TPS?

Cheers

Bennie

What year model is your engine?

What year models does your manual cover?

If the TPS was backwards, it would be giving you a lot more trouble than its giving you.

1991 Gen I - was meant to say that earlier...

The Haynes manual covers Liberties from 1989 onwards to '96 (?) I think... Its not a factory manual, that's for sure!

Only the voltage is backwards, not the resistance.

Cheers

Bennie

It may not be TPS, I was going to say, swap over MAP sensor to see if there is any change. I have a couple at home if you wanna borrow off me.
I remembered that I had jerky feel described what you said specially at low speed and was annoying, changed over MAP sensor and problem was solved.
Cheers
AP

Are you testing between the 5v supply and the sensor output or are you testing between ground and the sensor output?

This will reverse the readings

Suparoo wrote:Are you testing between the 5v supply and the sensor output or are you testing between ground and the sensor output?

This will reverse the readings

I've followed the instructions in the Haynes manual - double checked that I was doing it right, reversed the poles to get the same reading (digi doesn't do negative readings), re read the manual and did it again.

I'll have to dig up the manual tomorrow, its hiding in the junk that's taken up residence in the back of my subi...

AP by MAP sensor, do you mean Mass AirFlow sensor or??

Cheers

Bennie

Manifold Absolute Pressure seems to be the alternate doodad to an air flow meter AFM or Mass Air Flow sensor, has a vacuum reading device rather than intake air goin through it. You got some sort of air flow meter with a hotwire in it on your EJ? If so , no MAP sensor. Maybe AP means it could be your air measure device.

Crack in intake duct after AFM.MAP. etc?

steptoe wrote:Manifold Absolute Pressure seems to be the alternate doodad to an air flow meter AFM or Mass Air Flow sensor, has a vacuum reading device rather than intake air goin through it. You got some sort of air flow meter with a hotwire in it on your EJ? If so , no MAP sensor. Maybe AP means it could be your air measure device.

Crack in intake duct after AFM.MAP. etc?

Thats right sorry... MAF sensor.. not MAP...
Cheers
AP