TPS Voltage ????
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
TPS Voltage ????
What are you guys getting for WOT TPS voltage?
I'm getting +3.52 volts with the low end set to +.65 volts.
I just changed to an adjustable one and still can only get +3.76 volts with a 1.02 volt closed throttle setting.
The reference + 5.0 volts is good (checked it) at + 5.03 volts.
What's up with THIS???
What are you other folks getting?
Please.... NEED MO INPUT......
I'm getting +3.52 volts with the low end set to +.65 volts.
I just changed to an adjustable one and still can only get +3.76 volts with a 1.02 volt closed throttle setting.
The reference + 5.0 volts is good (checked it) at + 5.03 volts.
What's up with THIS???
What are you other folks getting?
Please.... NEED MO INPUT......
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: TPS Voltage ???? (VetNutJim)
Any chance that you are not getting WOT? Try manually opening the throttle to wide open at the throttle body and see if that makes it around 4.3v. Most of the time it never gets to 5 volts but should be around 4.3 to 4.9 volts.
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: TPS Voltage ???? (tjwong)
The +3.52 I'm getting IS with the throttle manually opened to the stop.
The accellerator pedal is opening to the same voltage, though.
I tried a new TPS on it last night. Got the same thing.
I've got 100% mechanical throttle opening but only 76% TPS voltage on Datamaster.
I thought sure the +5.0 reference would be low... but it wasn't.
It RUNS good, I just want it 'just right'.
The accellerator pedal is opening to the same voltage, though.
I tried a new TPS on it last night. Got the same thing.
I've got 100% mechanical throttle opening but only 76% TPS voltage on Datamaster.
I thought sure the +5.0 reference would be low... but it wasn't.
It RUNS good, I just want it 'just right'.
Pro
Joined: Apr 2003
Posts: 568
Likes: 12
From: Jacksonville Florida
Re: TPS Voltage ???? (VetNutJim)
The 5 volt source my be correct, but what about the integrity of the return line? In other words, when you read the 5 volt source, are you reading the hot line in reference to chassis, or are you reading it in reference to the return side of the TPS?
A crusty or resistive return will give you this indication. You have already verified the supply side, and swapped out the TPS, so my money is on the Return leg. :cheers:
A crusty or resistive return will give you this indication. You have already verified the supply side, and swapped out the TPS, so my money is on the Return leg. :cheers:
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: TPS Voltage ???? (Da Wiz)
The best thing to do is to probe and test the actual voltage level with a digital voltmeter. Da Wiz is right, a bad connection will cause a faulty reading. Probe pin C22 at the gray connector or probe it at the TPS sensor, its the dark blue wire. But I would think it would be easier to do this at the PCM connector. Use a small paper clip and insert it through the connector body to contact the pin, but don't force it, using a small paper clip the wire should just slide in and make contact with the PCM pin.
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: TPS Voltage ???? (Da Wiz)
Hey guys,
Don't get discouraged on this.
I'm reading the TPS voltage with leads DIRECTLY connected to the harness.
My digital meter ground is NOT connected to the engine block or anything.
I'm using one of the TPS voltage tester harness jigga-ma-things.
(Maybe I need to use a thinga-ma-bob) :) :) :lol:
I don't know what the deal is with this.
I guess I can look at my EPROM programming and see what it's using as a WOT value. If it's in a percentage or voltage I can determine if the ECM is thinking it's at WOT. If that's below what I've got then it won't matter.
Just seems a little strange the voltage is wrong.
This gadget is just a simple potentiometer.
Any more input?? Please.....
Edit: I can physically move the TPS 'slider' and it WILL adjust up pretty close to 5 volts. It's the mechanical link to the TB that's not moving it to 100% TPS voltage.
Note: I put an adjustable one on there last night.
When I adjust it up on the low side to get the HIGH side right, the low side is too much and it idles at 1100 rpm. That's with a 1.02 volt TPS setting.
So that idea didn't work out for me.
[Modified by VetNutJim, 1:09 PM 5/30/2003]
Don't get discouraged on this.
I'm reading the TPS voltage with leads DIRECTLY connected to the harness.
My digital meter ground is NOT connected to the engine block or anything.
I'm using one of the TPS voltage tester harness jigga-ma-things.
(Maybe I need to use a thinga-ma-bob) :) :) :lol:
I don't know what the deal is with this.
I guess I can look at my EPROM programming and see what it's using as a WOT value. If it's in a percentage or voltage I can determine if the ECM is thinking it's at WOT. If that's below what I've got then it won't matter.
Just seems a little strange the voltage is wrong.
This gadget is just a simple potentiometer.
Any more input?? Please.....
Edit: I can physically move the TPS 'slider' and it WILL adjust up pretty close to 5 volts. It's the mechanical link to the TB that's not moving it to 100% TPS voltage.
Note: I put an adjustable one on there last night.
When I adjust it up on the low side to get the HIGH side right, the low side is too much and it idles at 1100 rpm. That's with a 1.02 volt TPS setting.
So that idea didn't work out for me.
[Modified by VetNutJim, 1:09 PM 5/30/2003]
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: TPS Voltage ???? (VetNutJim)
Since my car came with an adjustable one, I have a little experience with them.
Note that d/t the curvature of the slots, you can slide the TPS front to back and also twist the sensor.
Generally when I have mine off and put it back on, I need to make an effort to make both a twisting adjustment and a sliding adjustment.
It will take a few minutes of tinkering with it...but mebbe this will be a step in the right direction. Perhaps you are only sliding it or only twisting it???
Good luck, -Matt
Note that d/t the curvature of the slots, you can slide the TPS front to back and also twist the sensor.
Generally when I have mine off and put it back on, I need to make an effort to make both a twisting adjustment and a sliding adjustment.
It will take a few minutes of tinkering with it...but mebbe this will be a step in the right direction. Perhaps you are only sliding it or only twisting it???
Good luck, -Matt
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: TPS Voltage ???? (HighHopes85)
I'll make sure I'm doing BOTH this afternoon. Sliding/twisting and doing the watoosi if that'll fix the darn thing. :lol:
The original one was non-adjustable but the adjustable one is a DIRECT replacement. (Sez me because I did it)
Will report back here later tonight.
The original one was non-adjustable but the adjustable one is a DIRECT replacement. (Sez me because I did it)
Will report back here later tonight.
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Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
I don't know how your ECM is, but my '87s from the factory is set to go into WOT mode (Power enrichment mode) at 69% of throttle which is 3.45 volts at the TPS. So you might not have to worry. :)
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: (scorp508)
Hey Scorp,
That was what I was thinking.
It's just one of those little things that bug the pdoody outta trying to make it be like the 'book' sez....
Anyway I'm going out to the garage and do another dance with it in a little while. It might not do any beter but I'll try again.
That was what I was thinking.
It's just one of those little things that bug the pdoody outta trying to make it be like the 'book' sez....
Anyway I'm going out to the garage and do another dance with it in a little while. It might not do any beter but I'll try again.
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: (VetNutJim)
FOUND IT....FIXED IT....FOUND IT....FIXED IT.... :thumbs: :thumbs:
Got 4.7 Volts NOW!!!!!!!!!!
I KNOW you guys are going to laugh at this one. (At ME)
Here's what the 'deal' was.
THE THROTTLE BODY BELLCRANK WAS HITTING THE AIR COUPLER RETAINER SCREW. :conehead :conehead :conehead :p:
I couldn't see it from the TPS side. Couldn't see it from inside the car.
The DVM was setting on top of the plenum while I pressed the acellerater pedal from inside the car so I could see what Iwas 'really' getting.
Couldn't see it was hitting that air coupler screw. :cuss :cuss
I swear it felt JUST LIKE the throttle stop.
Just happened to see it a few minutes ago while trying to slide & twist it the TPS.
Oh well easy and CHEAP fix.
Just goes to show no matter what, you can get got by a simple thing.
I think it's been this way for the last two years.
Can't wait to drive it tommorow with the additional 25% throttle available.
I guess I just 'thought' it was running good. (and it really was)
Had a 'built' in governor on it. :sad: :sad:
I AM SO EMBARRASSED!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Sorry to bother you, guys.
Got 4.7 Volts NOW!!!!!!!!!!
I KNOW you guys are going to laugh at this one. (At ME)
Here's what the 'deal' was.
THE THROTTLE BODY BELLCRANK WAS HITTING THE AIR COUPLER RETAINER SCREW. :conehead :conehead :conehead :p:
I couldn't see it from the TPS side. Couldn't see it from inside the car.
The DVM was setting on top of the plenum while I pressed the acellerater pedal from inside the car so I could see what Iwas 'really' getting.
Couldn't see it was hitting that air coupler screw. :cuss :cuss
I swear it felt JUST LIKE the throttle stop.
Just happened to see it a few minutes ago while trying to slide & twist it the TPS.
Oh well easy and CHEAP fix.
Just goes to show no matter what, you can get got by a simple thing.
I think it's been this way for the last two years.
Can't wait to drive it tommorow with the additional 25% throttle available.
I guess I just 'thought' it was running good. (and it really was)
Had a 'built' in governor on it. :sad: :sad:
I AM SO EMBARRASSED!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Sorry to bother you, guys.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
[QUOTECan't wait to drive it tommorow with the additional 25% throttle available.[/QUOTE]
:thumbs:
That happened to Mervz a couple of weeks ago. His throttle cable was loose and only had about 60% throttle. He was running 14.0 all day when his previous best was something like 13.5-13.6. Talk about a "DAMNIT thats all it was!?" moment. :)
:thumbs:
That happened to Mervz a couple of weeks ago. His throttle cable was loose and only had about 60% throttle. He was running 14.0 all day when his previous best was something like 13.5-13.6. Talk about a "DAMNIT thats all it was!?" moment. :)
Pro
Joined: Apr 2003
Posts: 568
Likes: 12
From: Jacksonville Florida
Re: TPS Voltage ???? (DragMan)
Welcome to the club..I had a misadjusted cable. But right on the heels of embarrassment came the delightful realization that I had 25 percent more throttle than I had twenty minutes ago.... :eek: :D
Don't you wish all lessons worked out that great, and cheap as well!! :cheers:
Don't you wish all lessons worked out that great, and cheap as well!! :cheers:
Thread Starter
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
Re: TPS Voltage ???? (VetNutJim)
Thanks for all your input, guys.
I checked some of my earlier DataMaster runs and this happened a few days ago when I put one of those %#^$%#%@% Air Foils on my TB.
I was getting pretty discouraged with it. My scanner was only showing 76% TPS voltage with my foot stuck thru the firewall.
I guess this shows that general maintenence procedures are valuable to find those 'technical errors' we make sometimes.
You guys are just the BEST!!
I checked some of my earlier DataMaster runs and this happened a few days ago when I put one of those %#^$%#%@% Air Foils on my TB.
I was getting pretty discouraged with it. My scanner was only showing 76% TPS voltage with my foot stuck thru the firewall.
I guess this shows that general maintenence procedures are valuable to find those 'technical errors' we make sometimes.
You guys are just the BEST!!
