TPS tech question EA82T

[rallyruss]

I need some one with a good meeter and an 82T(87-up hot wire type) to check the TPS signal for me on thier car.

I was running some tests on my car and found the TPS signal to be Inverted. I expected to find the reading to start low(.5v aprox) and slope up to 4.5 or so like most normal throttle position sensors work.

what I found was the exact opposite. my signal voltage is high at idle and drops as the throttle is opend.

now the tech info I have says that this is not correct. I would really appreaciate if some one could help me out here. I would hate to change it only to find that its normal and the info is wrong.

[NorthWet]

I won't have time to check until sometime this weekend. But I do have the car and the meter.

 

I also seem to recall that someone has posted that there is a difference between XT (XT6???) TPS and "normal" Ea82T's TPS. My foggy memory suggests that the progression was reversed between the two.

[All_talk]

According to the ’89 FSM I think your measurements are correct (see scans below). The test procedure show higher resistance at idle position, but it measures the sensor output terminal relative to ground (1 to 2), the output voltage is generated relative to the VDC input (2 to 3) which would be low resistance at idle.

 

Hmmm... pic host seems to be dorked right now, I'll up date later

 

 

 

Gary

[rallyruss]

thanks guys.

keep the info coming.

for all I know the motor could have been swaped with an XT turbo in the past. (it had 193,000 miles when I got it)

 

according to the diagram(thank you Gary) and my thoughts on resistance. I am reading backwards.

 

well I will wait for and actual verification from a known good car. Its been a long week my brain needs a rest.

[All_talk]

If I remember/get a chance I'll check my RX for you.

 

I need to fire it up and take it for a spin this weekend anyway, its been sitting all week cause I've been driving my new (to me) '92 Turbo Legacy.

 

Gary

[idosubaru]

i always do this since i only know one thing really well and not much about others - but in the XT6 FSM - the TPS testing procedures are dead wrong, not even close. no XT6 TPS will ever test within the specs of the factory service manual. if they do, then it's not working right!! so if they share TPS or are similar in that regards you may run into issues trying to match the FSM specs. again, XT6 related so it may not help you at all.

[Cougar]

Russ,

 

Are you sure you are on the right pins when you are measuring the voltage? If you were using the power supply pin as your reference then the voltage would change like you said.

[rallyruss]

Russ,

 

Are you sure you are on the right pins when you are measuring the voltage? If you were using the power supply pin as your reference then the voltage would change like you said.

 

I am positive about the pins. I checked all three to make sure what was what and that I had the correct reading. I understand what you mean though.

 

 

If the XT6 is the same as the EA82T then I think we are on to the problem (or lack there of)

 

It sucks that I only have one old school sube now to check.

[Steveman09]

I just recently replaced my TPS on my EA82-T due to a check engine light after about 1/4 throttle. I was also expierencing boost spikes, bad milage and rough idling.

 

When I calibrated my new sensor I got readings completly opposite from what you are saying so either you have a different sensor from a different motor/car that has different specs or your sensor is bad.

 

Do you have a code for the TPS?

[rallyruss]

I just recently replaced my TPS on my EA82-T due to a check engine light after about 1/4 throttle. I was also expierencing boost spikes, bad milage and rough idling.

 

When I calibrated my new sensor I got readings completly opposite from what you are saying so either you have a different sensor from a different motor/car that has different specs or your sensor is bad.

 

Do you have a code for the TPS?

 

no there are no codes stored. no real drivability issues either. The only reason I was testing it was for a class assignment involving graphing sensor data. its part of the new requirements for smog techs here. we have to show that we are capible of troubleshooting with all the proper equipment. long gone are the days of checking ohms on circits.