TPS reads 2.4% when throttle is closed. WTF?
#1
TPS reads 2.4% when throttle is closed. WTF?
This is wierd. Recently my car started doing something strange. When I would push in the clutch after driving for a while, I'd notice my idle was up around 1300 rpm (which is well above my normal idle speed of 850). I logged this and found out my TPS sensor was reading 2.4% even though my throttle was completely closed. That would bump my timing to the main spark table and raise my idle way more than normal.
Here's how it happens. I'll be driving along, let off the gas and the TPS reads 0% as always. Drive a little more then notice the higher idle and see that my TPS is reading 2.4%. I blip the throttle. Nothing. Still 2.4%. Raise the hood, see if there's tension on the cable. Nope. Throttle is completely closed.
I bought a brand new TPS sensor and swapped it in. Still doing it.
I swapped out my Nick Williams 90mm for another one...still doing it. WTF is going on? This is a total mystery to me that 2 different TPS sensor and 2 different throttle bodies would do this. What in the world could be causing my closed-TPS to jump from 0% to 2.4% right in the middle of driving?
Here's how it happens. I'll be driving along, let off the gas and the TPS reads 0% as always. Drive a little more then notice the higher idle and see that my TPS is reading 2.4%. I blip the throttle. Nothing. Still 2.4%. Raise the hood, see if there's tension on the cable. Nope. Throttle is completely closed.
I bought a brand new TPS sensor and swapped it in. Still doing it.
I swapped out my Nick Williams 90mm for another one...still doing it. WTF is going on? This is a total mystery to me that 2 different TPS sensor and 2 different throttle bodies would do this. What in the world could be causing my closed-TPS to jump from 0% to 2.4% right in the middle of driving?
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#3
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PG,
Log your idle follower and cracker PIDS to check that they are decayed to zero when it happens. Also log AC airflow adders, fan adders etc.
Could be you have some airflow adder, which is cracking open the IAC (don't know if yours is ETC) or blade, either way adding steps. You won't get idle control unitl all airflow adders are zeroed out.
BTW, I caught up with J-Rod when he was in AUS at the LS1 Nats, a few weeks back. Wish he had more time so we could talk **** and glean more info. about what you guys get up to over there...
Log your idle follower and cracker PIDS to check that they are decayed to zero when it happens. Also log AC airflow adders, fan adders etc.
Could be you have some airflow adder, which is cracking open the IAC (don't know if yours is ETC) or blade, either way adding steps. You won't get idle control unitl all airflow adders are zeroed out.
BTW, I caught up with J-Rod when he was in AUS at the LS1 Nats, a few weeks back. Wish he had more time so we could talk **** and glean more info. about what you guys get up to over there...
#4
Originally Posted by RedHardSupra
did you try resetting the TPS sensor? what kind of TPS voltage do you get with your foot off the gas completely?
When I start the car, the TPS reads 0%. It's after driving the car for a few minutes that the TPS sort of resets/re-indexes itself and the new closed-TPS reads 2.4%. Keep in mind, the throttle is completely closed, but the idle is raised (since timing goes from 18 degrees to 36 degrees). When I lower timing to 18 degrees in my main spark tables, the idle comes down. This is not IAC related. It is totally TPS related.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#5
Originally Posted by MNR-0
PG,
Log your idle follower and cracker PIDS to check that they are decayed to zero when it happens. Also log AC airflow adders, fan adders etc.
Could be you have some airflow adder, which is cracking open the IAC (don't know if yours is ETC) or blade, either way adding steps. You won't get idle control unitl all airflow adders are zeroed out.
Log your idle follower and cracker PIDS to check that they are decayed to zero when it happens. Also log AC airflow adders, fan adders etc.
Could be you have some airflow adder, which is cracking open the IAC (don't know if yours is ETC) or blade, either way adding steps. You won't get idle control unitl all airflow adders are zeroed out.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#7
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When did it start doing it? Has it always done it? Did you make a flash change and then it happened?
Check your main spark table, and cross-reference that with the actual spark realised during decel. and via the Histogram. 30+* timing is too much on decel - it will want to *hang* with no load and a converter pulling it up.
Try decreasing timing on your 0.04-0.08 rows in your main spark table to like 20*, and from 1400 down at 0.12 to 24*, blending it in up from there so you dont have huge spark swings causing *surging* on decel.
I am almost convinced it sounds timing related.
Check your main spark table, and cross-reference that with the actual spark realised during decel. and via the Histogram. 30+* timing is too much on decel - it will want to *hang* with no load and a converter pulling it up.
Try decreasing timing on your 0.04-0.08 rows in your main spark table to like 20*, and from 1400 down at 0.12 to 24*, blending it in up from there so you dont have huge spark swings causing *surging* on decel.
I am almost convinced it sounds timing related.
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#8
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Originally Posted by EDS01SS
Somebody else had a similiar problem on here.....try wiggling the wires at the TPS sensor and see if your readings change. The TPS connecter was bad on this other persons car
#10
OK, I swapped out the connector, and it's still doing it. It seems to reset my 0% TPS reference more often when I drive over very bumpy pavement. This problem is not throttle body related. The TPS is completely closed when the sensor gets whacked out and the idle is raised. Again, the high idle is due to the car thinking it's out of the base idle spark tables (18*) and in the main spark table (40*). When I lower the main spark table to 18*, the idle comes down close to 850rpm, even though the TB still reads 2.4-3.1%. Again, this is not a mechanical/linkage issue...it's electrical of some sort.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#11
So when the TPS% is at 2.4%, what is the logged TPS Voltage? If it persists, try raising the TPS Idle Enable setting just above 3.2% and see what happens? I had an issue with a car similar to this, it would stay at 5% TPS, it was electrical related since the voltage (when it happened) jumped up from .52V (max value for 0% TPS). This issue is not exclusively timing related, but rather timing table selection related ... IMHO.
PS: Also, try a different computer ... just for ***** and giggles. I had an ECM go 100% TPS with the actual TPS closed. Turned out to be a faulty ECM, when I swapped ECMs the issue went away. Just an idea.
PS: Also, try a different computer ... just for ***** and giggles. I had an ECM go 100% TPS with the actual TPS closed. Turned out to be a faulty ECM, when I swapped ECMs the issue went away. Just an idea.
#15
Originally Posted by 12secSS
So when the TPS% is at 2.4%, what is the logged TPS Voltage?
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#16
0.4V = 0%
0.4V = 2.4%
That is really f'ed up! I will look through my Helm's manual, I recall a proceedure to diagnose the TPS signal and associated control modules. Does your TA have traction control?
0.4V = 2.4%
That is really f'ed up! I will look through my Helm's manual, I recall a proceedure to diagnose the TPS signal and associated control modules. Does your TA have traction control?
#17
Originally Posted by 12secSS
0.4V = 0%
0.4V = 2.4%
That is really f'ed up! I will look through my Helm's manual, I recall a proceedure to diagnose the TPS signal and associated control modules. Does your TA have traction control?
0.4V = 2.4%
That is really f'ed up! I will look through my Helm's manual, I recall a proceedure to diagnose the TPS signal and associated control modules. Does your TA have traction control?
I have an EFI Live/Moates Road Runner for a PCM. It's been in the car for about a year and it's never given me a problem.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#19
Originally Posted by MCBRIZ28
just a shot in the dark check connectors to ecm have been seeing corrosion under a few lately and could be picking up false signal from it.
__________________
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2022 Cadillac Escalade 6.2L A10 S&B CAI, Corsa catback.
2023 Corvette 3LT Z51 soon to be modified.
Custom LSX tuning in person or via email press here.
#20
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Something to check is the female (PCM side) connector pin. Over time, the metal tabs spread apart which results in less than ideal metal-to-metal contact with the male part. This can cause erroneous readings like you are seeing. This happened to me on the TPS and fuel pressure sensor.