HELP!!! TPS will not adjust, confused!!
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
HELP!!! TPS will not adjust, confused!!
I have code 21 throwing on my 1985 C4. I followed the procedure found here to take a look at the TPS Voltage
http://www.iroczone.com/techarttpsadj.html
When i set my multimeter to 20 on the scale i get a contstand reading with the key in just the on position and the throttle closed of 4.79-4.82. I move it all the way in both directions with the torx bolts loosened and it will simply not move out of that range. I saw in the article written above that this guy had a initial reading of 4.39 and he was able to adjust it right to 0.540 where it is supposed to be. I have tried moving this thing in every possible way with NO change at all.
I do not know what to do at this point, please help!!!!!
http://www.iroczone.com/techarttpsadj.html
When i set my multimeter to 20 on the scale i get a contstand reading with the key in just the on position and the throttle closed of 4.79-4.82. I move it all the way in both directions with the torx bolts loosened and it will simply not move out of that range. I saw in the article written above that this guy had a initial reading of 4.39 and he was able to adjust it right to 0.540 where it is supposed to be. I have tried moving this thing in every possible way with NO change at all.
I do not know what to do at this point, please help!!!!!
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
hmm...wierd. I wouldn't think it could possibly be that high at closed throttle. I've played with it plenty of times, the highest I can make mine go is about 1 volt. . 38 is the lowest. Sounds like the sensor is bad, or the little (I don't know what you call it) thing that gets moved by the throttle blades could be stuck.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
When i open the throttle up it goes up a little to 4.95. I removed the tps cleaned it checked range of motion, reinstalled and still nothing but a solid 4.78-4.82 no matter how i position it
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
The part you referenced that should move when the throttle is opened does indeed move just fine. When i removed the TPS the inside had a dirty oily film on it but it moved well and cleaned up nicely.
Is there anything else this could be before i go buy another TPS or do these readings and my description pretty much confirm the sensor is bad??
The other odd things is if i start the car i can move the TPS wherever i want and the engine runs fine just the same but i still have code 21. Shouldnt the engine be giving me more problems??
I see the part at autozone for 30 bucks but at advance auto parts for 50-90 bucks, any difference
Is there anything else this could be before i go buy another TPS or do these readings and my description pretty much confirm the sensor is bad??
The other odd things is if i start the car i can move the TPS wherever i want and the engine runs fine just the same but i still have code 21. Shouldnt the engine be giving me more problems??
I see the part at autozone for 30 bucks but at advance auto parts for 50-90 bucks, any difference
Last edited by robertpel9; Feb 10, 2009 at 09:52 PM.
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
nada. I work at autozone myself, everything for my '85 has been cheapest at autozone.
While it sounds like the sensor is bad, the car should be running pig rich if that were the case.
Not questioning your tech skills, but to test the tps, you pierced the top two wires and had the multimeter set to dc volts correct?
While it sounds like the sensor is bad, the car should be running pig rich if that were the case.
Not questioning your tech skills, but to test the tps, you pierced the top two wires and had the multimeter set to dc volts correct?
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
nada. I work at autozone myself, everything for my '85 has been cheapest at autozone.
While it sounds like the sensor is bad, the car should be running pig rich if that were the case.
Not questioning your tech skills, but to test the tps, you pierced the top two wires and had the multimeter set to dc volts correct?
While it sounds like the sensor is bad, the car should be running pig rich if that were the case.
Not questioning your tech skills, but to test the tps, you pierced the top two wires and had the multimeter set to dc volts correct?
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
Also aren't my findings in line with the OBD code i am getting (21 = High Voltage at TPS)??
THis is all brand new to me, i am a rookie at this stuff so i am learning as i go, thanks for the patience
THis is all brand new to me, i am a rookie at this stuff so i am learning as i go, thanks for the patience
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Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
yes sir it is. 
The 34 could also make sense, that means mass air flow low voltage. If the computer sees the tps at WOT, and the maf is seeing idle, it could throw that 34.
Question for you, does it smell like a gas station out back when its running, or, any smoke if you rev it up? There should be.
The 34 could also make sense, that means mass air flow low voltage. If the computer sees the tps at WOT, and the maf is seeing idle, it could throw that 34.Question for you, does it smell like a gas station out back when its running, or, any smoke if you rev it up? There should be.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
No it really does not smell bad at all. I do not see smoke either and it idles fine'
Interestingly though when i went to get the safety inspection done thye had an issue where they gave it gas and the engine would bog out. The guy played with the throttle a bit and it was fine after that, it was also low on fuel and he thought maybe it just needed gas but i had just driven it there fine.
IDK i guess i can start by replacing the TPS if i plug it in and install it and still get the same reading i assume i can just bring it back
This is really ticking me off as i want an answer. The previous owner tells me he shot some parts cleaner into the MAF and TB when he got a light before and it went away but i dont know what the real deal is. Also why did the light go off for a week on its own and now it is back.
This is really P!ssing me off
Interestingly though when i went to get the safety inspection done thye had an issue where they gave it gas and the engine would bog out. The guy played with the throttle a bit and it was fine after that, it was also low on fuel and he thought maybe it just needed gas but i had just driven it there fine.
IDK i guess i can start by replacing the TPS if i plug it in and install it and still get the same reading i assume i can just bring it back
This is really ticking me off as i want an answer. The previous owner tells me he shot some parts cleaner into the MAF and TB when he got a light before and it went away but i dont know what the real deal is. Also why did the light go off for a week on its own and now it is back.
This is really P!ssing me off
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
The plot thickens, i was digging thru a box a parts that came with the car and i found a hypertech box for a streetrunner performance chip but the chip inside the box says delco!!!
Could this be a problem and how would i find where this performance chip is??
Could this be a problem and how would i find where this performance chip is??
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I'm sure it is in the ECM (car's computer)...doubt this is your problem though.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
Where is the ECM. I looked in the ALDL and there is nothing plugged into it, This chip i have has a back housing around it and the top of the chip says Delco FTT 9538
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Robert, just to be sure.....on the passanger side of the TB there is a tab (arm) attached to the butterfly shaft. When you give the TB some throttle by hand (car not running) this arm should rotate toward the front of the car and downward. This arm should be on top of the TPS arm so that when you give it throttle both arms should move together. Are they doing this?
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
Robert, just to be sure.....on the passanger side of the TB there is a tab (arm) attached to the butterfly shaft. When you give the TB some throttle by hand (car not running) this arm should rotate toward the front of the car and downward. This arm should be on top of the TPS arm so that when you give it throttle both arms should move together. Are they doing this?
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
In an '85 it is up under the passenger side of the dash. You'll have to remove the lower hush panel to access it....big fun. Again - if it were me I'd not complicate your issuse by tearing into other things right now.
Thread Starter
Safety Car
Joined: Nov 2001
Posts: 3,753
Likes: 191
From: Orange County California
Heck i'd love to leave it in if it is not issue but could i be replacing parts when the real issue is some BS chip??
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
The chip would not cause your problem.
FYI: The chip is located in the ECM which is located behind the passagner hush panel. You have to remove the panel...the ECM is located about in the center and is positioned up and down. Aluminum colored box about 7" wide, 1-1/2" thick and about 8-1/2" long. You will see one large plug and one smaller plug going into the bottom of the ECM with a bunch of wires going into each plug. You have to remove the plugs to pull out the ECM. Then you will find a removable panel about the same width of the ECM at the opposite end from the plugs. You have to remove this pannel and the chip will be found inside.
AT THIS POINT DON'T WORRY ABOUT THE CHIP. GET TO THAT LATTER.
FYI: The chip is located in the ECM which is located behind the passagner hush panel. You have to remove the panel...the ECM is located about in the center and is positioned up and down. Aluminum colored box about 7" wide, 1-1/2" thick and about 8-1/2" long. You will see one large plug and one smaller plug going into the bottom of the ECM with a bunch of wires going into each plug. You have to remove the plugs to pull out the ECM. Then you will find a removable panel about the same width of the ECM at the opposite end from the plugs. You have to remove this pannel and the chip will be found inside.
AT THIS POINT DON'T WORRY ABOUT THE CHIP. GET TO THAT LATTER.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Doesnt' a hypertech chip fool around with ait/fuel setting, etc. Could it be causing all fo this. I read an old thread where his problem was finally solved when a faulty peformance chip was replaced
Heck i'd love to leave it in if it is not issue but could i be replacing parts when the real issue is some BS chip??
Heck i'd love to leave it in if it is not issue but could i be replacing parts when the real issue is some BS chip??
Le Mans Master
Joined: Mar 2004
Posts: 5,107
Likes: 171
From: Dublin CA
Since both arms are moving when you move the throttle and you do have your meter connected to the top two wires and the reading is not changing....replace the TPS. The chip would react to the reading from the TPS.
The Hypertech chip is not the best in the world. You would be better sticking with the GM chip at this point.
The Hypertech chip is not the best in the world. You would be better sticking with the GM chip at this point.