TPS reads 2.4% when throttle is closed. WTF?
08-09-2007, 09:20 PM
#61
My car for example I can reset the TPS and it will go back to 0 but once I press the gas and move the throttle from the closed position it doesnt return to 0, it goes back to 2%.
With a cam my car would not idle with the TPS reading 2% because as long as the TPS was 2% my IAC would go to 0. I ended up having to basicly use my set screw and open up the throttle blade enough to where the TB was manualy allowing the airflow needed. Problem is that with it that far open it was too much for all conditions. When I would start my car up cold it would idle good and when it warmed up to a certain temperature the idle would shoot to 2500 for a few seconds and then come back down.
With a cam my car would not idle with the TPS reading 2% because as long as the TPS was 2% my IAC would go to 0. I ended up having to basicly use my set screw and open up the throttle blade enough to where the TB was manualy allowing the airflow needed. Problem is that with it that far open it was too much for all conditions. When I would start my car up cold it would idle good and when it warmed up to a certain temperature the idle would shoot to 2500 for a few seconds and then come back down.
08-10-2007, 07:13 PM
#62
Anybody having problems if the TPS voltage is less than .6 at idle?
I've done a bunch that we could get right to the .6+ voltage, and they would have inconsistent return to idle % values. Drill the throttle blade, get the closed throttle voltage below .6, and never, I mean never, have any problems.
When you get the closed throttle voltage that close to the threshold, by the time you figure in the increased voltage from the charging system, and the fluctuation from on and off the throttle, increasing and decreasing the supply voltage, which in turn varies the return voltage, its pretty easy to see how you can have a varying percentage.
Its not any secret ****. Sounds like most are running the closed throttle voltage too close to the threshold.
Just my dumb *** opinion/input......
I've done a bunch that we could get right to the .6+ voltage, and they would have inconsistent return to idle % values. Drill the throttle blade, get the closed throttle voltage below .6, and never, I mean never, have any problems.
When you get the closed throttle voltage that close to the threshold, by the time you figure in the increased voltage from the charging system, and the fluctuation from on and off the throttle, increasing and decreasing the supply voltage, which in turn varies the return voltage, its pretty easy to see how you can have a varying percentage.
Its not any secret ****. Sounds like most are running the closed throttle voltage too close to the threshold.
Just my dumb *** opinion/input......
08-12-2007, 09:37 PM
#63
Originally Posted by edcmat-l1
Anybody having problems if the TPS voltage is less than .6 at idle?
I've done a bunch that we could get right to the .6+ voltage, and they would have inconsistent return to idle % values. Drill the throttle blade, get the closed throttle voltage below .6, and never, I mean never, have any problems.
When you get the closed throttle voltage that close to the threshold, by the time you figure in the increased voltage from the charging system, and the fluctuation from on and off the throttle, increasing and decreasing the supply voltage, which in turn varies the return voltage, its pretty easy to see how you can have a varying percentage.
Its not any secret ****. Sounds like most are running the closed throttle voltage too close to the threshold.
Just my dumb *** opinion/input......
I've done a bunch that we could get right to the .6+ voltage, and they would have inconsistent return to idle % values. Drill the throttle blade, get the closed throttle voltage below .6, and never, I mean never, have any problems.
When you get the closed throttle voltage that close to the threshold, by the time you figure in the increased voltage from the charging system, and the fluctuation from on and off the throttle, increasing and decreasing the supply voltage, which in turn varies the return voltage, its pretty easy to see how you can have a varying percentage.
Its not any secret ****. Sounds like most are running the closed throttle voltage too close to the threshold.
Just my dumb *** opinion/input......
have had it in the .4s and .5s the whole time
08-12-2007, 10:22 PM
#64
Originally Posted by Patrick G
This problem has not gone away. I am about to burn the car to the ground! 
Hehe.
Originally Posted by Full-Force
My car for example I can reset the TPS and it will go back to 0 but once I press the gas and move the throttle from the closed position it doesnt return to 0, it goes back to 2%.
With a cam my car would not idle with the TPS reading 2% because as long as the TPS was 2% my IAC would go to 0. I ended up having to basicly use my set screw and open up the throttle blade enough to where the TB was manualy allowing the airflow needed. Problem is that with it that far open it was too much for all conditions. When I would start my car up cold it would idle good and when it warmed up to a certain temperature the idle would shoot to 2500 for a few seconds and then come back down.
With a cam my car would not idle with the TPS reading 2% because as long as the TPS was 2% my IAC would go to 0. I ended up having to basicly use my set screw and open up the throttle blade enough to where the TB was manualy allowing the airflow needed. Problem is that with it that far open it was too much for all conditions. When I would start my car up cold it would idle good and when it warmed up to a certain temperature the idle would shoot to 2500 for a few seconds and then come back down.
You may edit your tune to cope with this issue. I know it doesn't make the system work as it should but still.
Any non-zero value will throw you out of idle mode. This problem is throwing you out of the spark maps you think you are using any many other parameters as well.
If you have EFI-Live the Max Throttle for Idle Mode {B0108} might be adjusted to help with this issue.
Hope you can get this fixed.
Last edited by 2002_Z28_Six_Speed; 08-12-2007 at 10:28 PM.
08-12-2007, 11:07 PM
#65
Originally Posted by 2002_Z28_Six_Speed
Sell me your car before you do that. Or just trade me. Hehe.
You may edit your tune to cope with this issue. I know it doesn't make the system work as it should but still.
Any non-zero value will throw you out of idle mode. This problem is throwing you out of the spark maps you think you are using any many other parameters as well.
If you have EFI-Live the Max Throttle for Idle Mode {B0108} might be adjusted to help with this issue.
Hope you can get this fixed.
Hehe.You may edit your tune to cope with this issue. I know it doesn't make the system work as it should but still.
Any non-zero value will throw you out of idle mode. This problem is throwing you out of the spark maps you think you are using any many other parameters as well.
If you have EFI-Live the Max Throttle for Idle Mode {B0108} might be adjusted to help with this issue.
Hope you can get this fixed.
08-13-2007, 01:31 AM
#67
Originally Posted by RedHardSupra
it's under engine->airflow->dynamic airflow, you got two: idle zone tps and idle zone vss
08-13-2007, 01:20 PM
#68
Originally Posted by Nick Williams
I just got finished working on a 98' having the same problem. Decided to check the fit of the TPS on the throttle shaft. Found that it was loose and had absolutely no press fit. What I done was wrapped some clear tape around the shaft til the sensor went on tight. Then reset the TPS by unpugging it and turning key on. Problem has completey gone away and the car runs great now.
Nick
Nick
08-14-2007, 12:17 PM
#71
One of the biggest problems contributing to this situation comes from bad grounds. It was suggested by another board member (98Aggie) to run a dedicated ground from the TPS ground wire directly to the body. He feels this will eliminate the majority of these problems. Ever since I separated and retaped the wires, I have not had the problem, but if it returns, I will run the dedicated ground wire. Does anyone know what color the TPS ground wire is?
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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.
08-14-2007, 12:34 PM
#72
Originally Posted by Patrick G
One of the biggest problems contributing to this situation comes from bad grounds. It was suggested by another board member (98Aggie) to run a dedicated ground from the TPS ground wire directly to the body. He feels this will eliminate the majority of these problems. Ever since I separated and retaped the wires, I have not had the problem, but if it returns, I will run the dedicated ground wire. Does anyone know what color the TPS ground wire is?
08-14-2007, 07:03 PM
#74
An update from our car. We installed a Holley TB and it seemed to have fix the voltage issue. Been on for about 3 weeks and so far so good. It seems like there are a few different issues causing this problem based on what has helped a few folks here. Patrick with seperating wires, Nick with making sure the TPS contact to the shaft is tight and another with e new TPS. Best to everyone on this.
Mike Norris
Mike Norris
08-22-2007, 04:18 PM
#76
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Had this problem as well. Grabbed a different Maf and IAT sensor, problem is gone. From time to time the car will raise up to like 1300-1500 rpm, as I am coming to a stop. once the car is stopped, Idle is fine. 98 pcm, cable throttle, Sorry no tuning software at the time to take logs - But I checked the grounds for unmetered air leaks and such and just happened to change out the MAf and IAT as a test.
09-14-2007, 05:05 PM
#77
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I lied, Its back. Car was running great for 3-4 weeks with the new MAF and IAT- Using HP Tuners my car shows Throttle Position as 0% during the periods of high reving, but when the car is stopped a lot of the time the car will show 2-4 MPH... Still looking into this - Bump.
09-15-2007, 03:04 PM
#78
Looking at things now with EFILive I can see that I have an electrical issue. Most likely, hopefully a ground is broken either at the connector or within its own insulation. (wave lengths all looking the same for different sensors and screwy readings on the sensors)
Shouldnt be that hard to fix if its just a ground. The ecm has two directly off the blue and red connectors. I'll start there. I know there are other grounds but the values I'm seeing for VSS, MAP, TPS and a few other sensors are all on one side for the ground so thats where I'm starting with my ohn meter. I could just run a new ground and check it I suppose. Take the easy way out if it's just the ground. A hot lead grounding is a different story. That can be a total nightmare.
But I've got multiple sensors throwing screwy readings. -41 at startup coolant at 30 degrees.... they cant all be arc'ed out.... I'll report back.
Shouldnt be that hard to fix if its just a ground. The ecm has two directly off the blue and red connectors. I'll start there. I know there are other grounds but the values I'm seeing for VSS, MAP, TPS and a few other sensors are all on one side for the ground so thats where I'm starting with my ohn meter. I could just run a new ground and check it I suppose. Take the easy way out if it's just the ground. A hot lead grounding is a different story. That can be a total nightmare.
But I've got multiple sensors throwing screwy readings. -41 at startup coolant at 30 degrees.... they cant all be arc'ed out.... I'll report back.
09-16-2007, 09:37 AM
#80
No luck. Going to start with the VSS as it shows I'm doing 30mph while sitting there idling. With the key on and car not started it shows 0. The IAT and Coolant temp show as -41 at startup.
It is possible that when the car got stuffed into the muddy embanklment that something was hosed under there. It was full of mud and dirt.
With the IAT and other sensors not reading right the tune is screwed, Running too rich.
It is possible that when the car got stuffed into the muddy embanklment that something was hosed under there. It was full of mud and dirt.
With the IAT and other sensors not reading right the tune is screwed, Running too rich.
Last edited by 99blancoSS; 09-16-2007 at 10:24 AM.