Adjusted TPS to 0.54, now idles at 1300
#61
Racer
Thread Starter
Nope... Picked up my new Delco p/n 213-905, checked it first by running the 10g jump wires from 5v reference and ground, then measured middle pin output. WOT: 3.2v. Literally not kidding.
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
#62
Race Director
Nope... Picked up my new Delco p/n 213-905, checked it first by running the 10g jump wires from 5v reference and ground, then measured middle pin output. WOT: 3.2v. Literally not kidding.
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
#63
Racer
Thread Starter
This whole thing just blows my mind. Two bad BWD TPS and a bad Delco. I'm not even sure I want to order a new unit anymore, it seems the manu. tolerances are garbage. Third gen Camaros tend to plentiful around here, especially in the JY
#64
Nope... Picked up my new Delco p/n 213-905, checked it first by running the 10g jump wires from 5v reference and ground, then measured middle pin output. WOT: 3.2v. Literally not kidding.
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
It seems like on all of these bad sensors, the first 20-25% of lever travel produces no voltage. I still installed it to try something. Installed and angled all the way up, with the set screw completely screwed in, the most it'll read at "idle"' was .30. At this point all I can do is laugh. I don't believe there is a way I can adjust the actual lever. Maybe I need to hit the junk yards tomorrow and find an authentic period correct 3 wire GM TPS
i.e., a test lead from MAP or MAF 5v pin to the tps bottom socket, a test lead from MAP or MAF ground to pin top socket, then measure voltage between the signal and ground wire.
I'm not 100% convinced the sensor is bad, doing a bench test or using differnt wiring would help shift the blame off the TPS. The no tps voltage uptake until 25% just reminds me exactly of what happened when I wired my MAP sensor backward. Because my MAP and TPS shared a ground, the backwards wiring (5v to ground, ground to 5v) on the MAP threw the TPS off.
#65
Racer
Thread Starter
Jesus. We did confirm that the signal wire had low resistance right? At this point it may be worth finding a 5v power supply and bench testing the TPS sensor. That way we can know if it's the wiring or not. Alternatively, you could jumper +5v and ground from any other 5 volt sensor's connector (MAP or MAF, for example) and measure the signal voltage.
i.e., a test lead from MAP or MAF 5v pin to the tps bottom socket, a test lead from MAP or MAF ground to pin top socket, then measure voltage between the signal and ground wire.
I'm not 100% convinced the sensor is bad, doing a bench test or using differnt wiring would help shift the blame off the TPS. The no tps voltage uptake until 25% just reminds me exactly of what happened when I wired my MAP sensor backward. Because my MAP and TPS shared a ground, the backwards wiring (5v to ground, ground to 5v) on the MAP threw the TPS off.
i.e., a test lead from MAP or MAF 5v pin to the tps bottom socket, a test lead from MAP or MAF ground to pin top socket, then measure voltage between the signal and ground wire.
I'm not 100% convinced the sensor is bad, doing a bench test or using differnt wiring would help shift the blame off the TPS. The no tps voltage uptake until 25% just reminds me exactly of what happened when I wired my MAP sensor backward. Because my MAP and TPS shared a ground, the backwards wiring (5v to ground, ground to 5v) on the MAP threw the TPS off.
#66
I think a good bench test is def in the works. I was incredibly careful to make sure I ran wires appropriately for this test. I made sure it was getting 5v from reference and confirmed it stayed 5v throughout the range. The MAF is a new Bosch unit and the connector only fits in one way. Chances of that being messed up?? And yessir, confirmed I had 0 ohm resistance on the signal wire (we went through the de-pinning process). I started to think it was the car, but then I realized that the BWDs read different outputs, one below 2, the other just over 2, and now the Delco reads 3.2. If the car was at fault, I would imagine it would be failing at similar voltage outputs?
If the issue was like mine, I would suspect consistent outputs from the TPS sensors. But if there was a bad ground, the signal voltage could be different.
#67
Team Owner
I think a good bench test is def in the works. I was incredibly careful to make sure I ran wires appropriately for this test. I made sure it was getting 5v from reference and confirmed it stayed 5v throughout the range. The MAF is a new Bosch unit and the connector only fits in one way. Chances of that being messed up?? And yessir, confirmed I had 0 ohm resistance on the signal wire (we went through the de-pinning process). I started to think it was the car, but then I realized that the BWDs read different outputs, one below 2, the other just over 2, and now the Delco reads 3.2. If the car was at fault, I would imagine it would be failing at similar voltage outputs?
#68
#70
Racer
Thread Starter
About to do that as well. With such a nice day today, I was looking forward to getting some miles in
#71
You're right, I did. I phrased that bad in the post. I was coming off a 30 hour shift... TPS off the car and arm cranked all the way down got me like 3.4.
So here is what I just did. Sensor off the car, I did use the 5v feed from the connector, but then I grounded out the top pin to chassis to remove any other sensor interference. Confirmed it was receiving and grounding 5v. Measured voltage from the middle pin and received exactly the same as I did from the initial test. To even get to 0.54v, the arm was like halfway through the rotation. Only thing that all this comes back to is bad manu. tolerances of these "new old" parts. Going to hit the JY later this morning and see if I can find an original TPS
About to do that as well. With such a nice day today, I was looking forward to getting some miles in
So here is what I just did. Sensor off the car, I did use the 5v feed from the connector, but then I grounded out the top pin to chassis to remove any other sensor interference. Confirmed it was receiving and grounding 5v. Measured voltage from the middle pin and received exactly the same as I did from the initial test. To even get to 0.54v, the arm was like halfway through the rotation. Only thing that all this comes back to is bad manu. tolerances of these "new old" parts. Going to hit the JY later this morning and see if I can find an original TPS
About to do that as well. With such a nice day today, I was looking forward to getting some miles in
#72
Racer
Thread Starter
Junk yards were fruitless. Stopped by a friend's shop that used to be a gm dealership back in the late 80s and early 90s, the parts room is untouched since it shut down. No TPS in the old stock. But found some sweet stuff in there. Old SBC heads never installed still in their factory wrap.
Stopped off at advance and talked to them about the issues. We talked over some options and they found an alternate part number for a BWD TPS using 3rd gen L98 Camaro info. It was like twice the price of the other one, ACDelco territory. I'll have it in the morning and we'll roll the dice on this one. Worst worst case, i'll stop off at the dealership and see what they think
Stopped off at advance and talked to them about the issues. We talked over some options and they found an alternate part number for a BWD TPS using 3rd gen L98 Camaro info. It was like twice the price of the other one, ACDelco territory. I'll have it in the morning and we'll roll the dice on this one. Worst worst case, i'll stop off at the dealership and see what they think
#73
Racer
Thread Starter
New alternate pn for the TPS and got 3.4 at WOT. I ohm'd both of the TPSs (BWD and Delco) and got the below results. They seem in line from the ones referenced earlier in this thread. I just want to bang my head. How can this be this difficult, 4 TPS reading low voltage when receiving 5v reference...
BWD
A-C: 6.79
A-B: 3.3
C-B: 9.8
Rotating sweep
A-B: 3-8
C-B: 9.8-2
Delco
A-C: 6.74
A-B: 3.4
C-B: 9.8
Rotating Sweep
A-B: 3.4-8.3
C-B: 9.8-1.5
BWD
A-C: 6.79
A-B: 3.3
C-B: 9.8
Rotating sweep
A-B: 3-8
C-B: 9.8-2
Delco
A-C: 6.74
A-B: 3.4
C-B: 9.8
Rotating Sweep
A-B: 3.4-8.3
C-B: 9.8-1.5
#74
Drifting
n Autozone Duralast should work fine. Mine has been fine for over a year.
I do notice they start in the more rotated position to get .54, but you have to move the tps sensor around a little more than stock.
I do notice they start in the more rotated position to get .54, but you have to move the tps sensor around a little more than stock.
#75
Racer
Thread Starter
Getting to 0.54 isn’t really the issue, it’s the fact that none of the 4 brand new sensors I’ve bought will read over 3.5v at WOT. They all read low at WOT. I’m curious now if I can notch the cut off nub that stops it at “WOT” so the lever can continue to progress and get higher voltage
#76
Drifting
I am pretty sure WOT is anything 3.5 and over. Start it over .54 and get an error. Here is a read on the subject.
https://www.corvetteforum.com/forums...ain-still.html
I have never checked mine other than it went up and down smooth.
https://www.corvetteforum.com/forums...ain-still.html
I have never checked mine other than it went up and down smooth.
Last edited by xrav22; 06-03-2018 at 03:25 PM.
#77
Racer
Thread Starter
I am pretty sure WOT is anything 3.5 and over. Start it over .54 and get an error. Here is a read on the subject.
https://www.corvetteforum.com/forums...ain-still.html
I have never checked mine other than it went up and down smooth.
https://www.corvetteforum.com/forums...ain-still.html
I have never checked mine other than it went up and down smooth.
#78
Racer
Thread Starter
Ok...Update. Bought an original working TPS from another forum member from an 88. It actually works! Got it installed and went through the entire idle reset process, followed every word. Took it out for a spin and everything seemed like it was on track, idled between 7-8, great throttle response, car just felt more alive. Stopped for gas, obviously turned the car off, filled up, then restarted the car and it immediately idled at 1500
It absolutely would not kick down to anything less than 1500. Came home and popped the hood and I heard a little hiss that I hadn't heard before. Seems like I have a vac leak at the brake booster vac line elbow. Pushed in on the fitting and the hiss stopped, but the high idle did not. I'm confident the idle set screw and TPS are where they need to be. It worked well before tuning off. With IAC pintle fulled extended (A+B jumped, disconnected, etc.), it'll idle between 4-5. I know vac leaks can lead to a high idle, but I don't think 1500 would happen from a vac leak like that would it?
It absolutely would not kick down to anything less than 1500. Came home and popped the hood and I heard a little hiss that I hadn't heard before. Seems like I have a vac leak at the brake booster vac line elbow. Pushed in on the fitting and the hiss stopped, but the high idle did not. I'm confident the idle set screw and TPS are where they need to be. It worked well before tuning off. With IAC pintle fulled extended (A+B jumped, disconnected, etc.), it'll idle between 4-5. I know vac leaks can lead to a high idle, but I don't think 1500 would happen from a vac leak like that would it?
#79
Ok...Update. Bought an original working TPS from another forum member from an 88. It actually works! Got it installed and went through the entire idle reset process, followed every word. Took it out for a spin and everything seemed like it was on track, idled between 7-8, great throttle response, car just felt more alive. Stopped for gas, obviously turned the car off, filled up, then restarted the car and it immediately idled at 1500
It absolutely would not kick down to anything less than 1500. Came home and popped the hood and I heard a little hiss that I hadn't heard before. Seems like I have a vac leak at the brake booster vac line elbow. Pushed in on the fitting and the hiss stopped, but the high idle did not. I'm confident the idle set screw and TPS are where they need to be. It worked well before tuning off. With IAC pintle fulled extended (A+B jumped, disconnected, etc.), it'll idle between 4-5. I know vac leaks can lead to a high idle, but I don't think 1500 would happen from a vac leak like that would it?
It absolutely would not kick down to anything less than 1500. Came home and popped the hood and I heard a little hiss that I hadn't heard before. Seems like I have a vac leak at the brake booster vac line elbow. Pushed in on the fitting and the hiss stopped, but the high idle did not. I'm confident the idle set screw and TPS are where they need to be. It worked well before tuning off. With IAC pintle fulled extended (A+B jumped, disconnected, etc.), it'll idle between 4-5. I know vac leaks can lead to a high idle, but I don't think 1500 would happen from a vac leak like that would it?
I was working on the girlfriends 86 this weekend, chasing a high idle. The idle reset process worked for it, but it would jump up when the engine light for IAT sensor came on when idling for ~30 secs after warming up.
So for whats it's worth, check for any trouble codes. A big enough vac leak may have set a code.
A bolt recently shook it's way out of my plenum, which led to an idle that was either 500, or 1200, it would jump up and down. That was a big leak, but is an example of how goofy the computer can respond to a leak.
#80
Racer
Thread Starter
Good lord, it really was a bunch of bad sensors. What a mess!
I was working on the girlfriends 86 this weekend, chasing a high idle. The idle reset process worked for it, but it would jump up when the engine light for IAT sensor came on when idling for ~30 secs after warming up.
So for whats it's worth, check for any trouble codes. A big enough vac leak may have set a code.
A bolt recently shook it's way out of my plenum, which led to an idle that was either 500, or 1200, it would jump up and down. That was a big leak, but is an example of how goofy the computer can respond to a leak.
I was working on the girlfriends 86 this weekend, chasing a high idle. The idle reset process worked for it, but it would jump up when the engine light for IAT sensor came on when idling for ~30 secs after warming up.
So for whats it's worth, check for any trouble codes. A big enough vac leak may have set a code.
A bolt recently shook it's way out of my plenum, which led to an idle that was either 500, or 1200, it would jump up and down. That was a big leak, but is an example of how goofy the computer can respond to a leak.