82 TPS Question
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Well..I got my factory service manual and was going to post you stuff....I also got my 1989 factory service manual that has mroe information in it than the 1982 book has...and it does not matter if it is a Tuned Port or Cross-Fire.
Hopefully your new TPS does the trick. If not..I will post stuff for you that may help.
DUB
Hopefully your new TPS does the trick. If not..I will post stuff for you that may help.
DUB
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
The TPS is more or less a potentiometer. The 5V is across the fixed resistance and the output is the wiper.
Your description sounds like a mechanical issue with the throttle body not returning to the same spot when the butterflies move. Measure voltage while you cycle the throttle opened and closed. the voltage should respond nice and linearly to the throttle movement and it should always have the same voltage each time the throttle reaches the fully open and the fully closed positions. If not, then you likely have a mechanical issue in the throttle body. I suggest pulling on or at the throttle cable to best simulate the throttle operation when in use.
There will not be a capacitor causing a large lag in the TPS output response. If that were true, the TPS would be useless since it's output would not indicate the real time throttle position to the ECM.
Your description sounds like a mechanical issue with the throttle body not returning to the same spot when the butterflies move. Measure voltage while you cycle the throttle opened and closed. the voltage should respond nice and linearly to the throttle movement and it should always have the same voltage each time the throttle reaches the fully open and the fully closed positions. If not, then you likely have a mechanical issue in the throttle body. I suggest pulling on or at the throttle cable to best simulate the throttle operation when in use.
There will not be a capacitor causing a large lag in the TPS output response. If that were true, the TPS would be useless since it's output would not indicate the real time throttle position to the ECM.
Last edited by lionelhutz; Aug 10, 2016 at 09:17 AM.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,143
Likes: 488
From: Leonardtown Maryland
I agree with everything you say which is why I've been chasing my tail and asked all the questions about resistance. The only time it looked correct was with voltage applied, but even then when I physically held the butterfly on the throttle body the voltage was changing. So I tried to read between the input to wiper, and ground to wiper, and found 0 ohms. Seems to me that I should have some resistance reading which should change as I move the wiper. I can't find any reference for our specific TPS so when I get my new one I will baseline and post the results.Thanks for the reply - Chris
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
I agree with everything you say which is why I've been chasing my tail and asked all the questions about resistance. The only time it looked correct was with voltage applied, but even then when I physically held the butterfly on the throttle body the voltage was changing. So I tried to read between the input to wiper, and ground to wiper, and found 0 ohms. Seems to me that I should have some resistance reading which should change as I move the wiper. I can't find any reference for our specific TPS so when I get my new one I will baseline and post the results.Thanks for the reply - Chris
I can understand that if you are holding the throttle partially open and your voltage at the TPS is going all over the place and YET the throttle is NOT moving. I would be SUSPECT of the TPS....OR
I would test the TPS NOT using the wiring signal from the ECM and run my own wiring and check it as if it were connected to the ECM and see if it goes all over the place.
Because there can be an issue internally in the ECM.
Because if you get several TPS' and they all are doing the same thing...the odds that they are all bad is highway unlikely.
Just 'brainstorming' with you...and that is because I ASSUME NOTHING...and check things that often times seem to not be probable.
DUB
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,143
Likes: 488
From: Leonardtown Maryland
LOL, Wiper is a term I am familiar with in regards to a the arm on a variable resister that provides the varying voltage/resistance. No other wipers have been injured in the making of this forum posting.
And Dub, I agree with everything you say in the previous post.
Thanks - Chris
And Dub, I agree with everything you say in the previous post.
Thanks - Chris
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Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
I would be double checking my ohmmeter if I were you. Get a 1k ohm and 100k ohm resistors and make sure it will read them. You constantly getting 0 ohms or an open circuit when testing different TPSs makes little sense.
Also, you could check between the 5V and the GND to ensure the circuit has a good constant 5V on it. Your wiper voltage would keep changing if that voltage was varying.
I believe the TPS should read 5k ohms between the 5V and GND terminals. If you can't read this resistance then I would be really suspect of the meter.
Also, you could check between the 5V and the GND to ensure the circuit has a good constant 5V on it. Your wiper voltage would keep changing if that voltage was varying.
I believe the TPS should read 5k ohms between the 5V and GND terminals. If you can't read this resistance then I would be really suspect of the meter.
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,143
Likes: 488
From: Leonardtown Maryland
Yep, I read 4.6K Ohms between pins A and C on the TPS I returned. Zero Ohms between B and either A or C. Just my luck to get a TPS that was either getting ready to die, or was DOA. Wish I could be that luck with Power Ball. I bought it through Amazon Prime so my new one should be here soon.
R - Chris
R - Chris
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
Something is wrong besides the sensor. The measurements you are getting don't add up. If you read 0 ohms between A and B and 0 ohms between B and C then you should also read 0 ohms between A and C.
2nd Gear
Joined: Aug 2016
Posts: 2
Likes: 0
82 tps
I have one coming as well, so interested to see how this turns out....Now, the weird part for me is. When I bought the car 2 weeks ago it was running and idling very well with a hesitation if accelerated very heavy. I was getting a fault code of 51 which indicated a bad Prom, so just got the new one installed yesterday and now it doesn't idle well and seems to run very rich and can smell gas very strong. Hoping the TPS will help out now that I'm running with a good chip.
Zen Vet Master Level VII
Joined: Mar 2016
Posts: 5,218
Likes: 1,174
From: Southlake, TX
[QUOTE Prom, so just got the new one installed yesterday and now it doesn't idle well and seems to run very rich and can smell gas very strong. Hoping the TPS will help out now that I'm running with a good chip.[/QUOTE]
You need to run the car a bit so the computer resets. Take it for a ride where you can have variable speeds and report back.
You need to run the car a bit so the computer resets. Take it for a ride where you can have variable speeds and report back.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
And I hope you have a scanner so you can read data. Attempting to trouble shoot this type of car can be done without one but you will need to have a lot of jumper leads. And the scanners for this type of car are so cheap now due to being outdated....you can pick up an old Snap-On 'red brick' scanner for darn near nothing.
DUB
2nd Gear
Joined: Aug 2016
Posts: 2
Likes: 0
Tps
And I hope you have a scanner so you can read data. Attempting to trouble shoot this type of car can be done without one but you will need to have a lot of jumper leads. And the scanners for this type of car are so cheap now due to being outdated....you can pick up an old Snap-On 'red brick' scanner for darn near nothing.
DUB[/QUOTE]
I installed the new TPS yesterday and it made all the difference in the world. I took it out for a couple of 10 mile trips today and runs very well and idles smoothly at about 800 rpm's. The only thing I notice now is that when I excellerate very heavy, I can feel a vibration. It doesn't seem to be effected by the speed. It feels as if it vibrates more the heavier I mash on the gas and when I let up it seems to almost go away.
Last edited by 1982CE; Aug 13, 2016 at 09:59 PM.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
Then it seems to be an 'under load condition'...It can be bad gas, timing or ignition related and other things that may show up if you had a scanner connected to it...or worn out engine or transmission mounts....who knows.
DUB
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 2,143
Likes: 488
From: Leonardtown Maryland
My new TPS came in yesterday so here are the "at rest" resistance test results. I understand this is just a sanity check but it might help somebody:
A - C (power to ground) 4.84 K Ohms
C - B 5.91 K Ohms
A - B 1.07 K Ohms
A - B (Power off but with TPS installed and adjusted to .525 VDC) 1.567 K Ohms.
The new TPS works correctly and I was able to run the motor for ten minutes and it never missed a beat. Idle was about 1000 RPM and I could rev it up and back without any problems. While waiting for the TPS I replaced the thermostat, water temp sensor and water temp gauge sensor.
Earlier I had to pull the center instrument cluster to replace lamp bulbs and the circuit board. The water temp gauge hasn't worked for a while and thankfully it was just a bad sensor. Planning a test drive this afternoon. If all is good I'm looking forward to a little cruising and when cold weather comes in to rebuilding the throttle bodies.
Thanks for all the advice provided!
-Chris
Update: 30 minute drive later and the car is still running good!
A - C (power to ground) 4.84 K Ohms
C - B 5.91 K Ohms
A - B 1.07 K Ohms
A - B (Power off but with TPS installed and adjusted to .525 VDC) 1.567 K Ohms.
The new TPS works correctly and I was able to run the motor for ten minutes and it never missed a beat. Idle was about 1000 RPM and I could rev it up and back without any problems. While waiting for the TPS I replaced the thermostat, water temp sensor and water temp gauge sensor.
Earlier I had to pull the center instrument cluster to replace lamp bulbs and the circuit board. The water temp gauge hasn't worked for a while and thankfully it was just a bad sensor. Planning a test drive this afternoon. If all is good I'm looking forward to a little cruising and when cold weather comes in to rebuilding the throttle bodies.
Thanks for all the advice provided!
-Chris
Update: 30 minute drive later and the car is still running good!
Last edited by Bigredwing; Aug 20, 2016 at 11:42 AM. Reason: Added update