Aftermarket TB/Plenum Hanging idle/low idle issues!
07-21-2008, 11:09 PM
#1
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Aftermarket TB/Plenum Hanging idle/low idle issues!
I've noticed that there are a lot of guys that have done the Aftermarket TB/Plenum swap and are having problems with hanging idle/low idle issues!
I just got done installing a Trickflow Plenum/75mm TB swap and am having the same issues. I've been doing some investigating and have a few questions/observations for you pros that may help others also.
1. I installed a new TPS on the TB so I don't think I have any issues with the TPS itself although I'm not sure if there is a specific position that the TB blade guide to TPS needs to be in other than closed and you just put the TPS on as is? I assumed that the ECU will self position so there was no need to install it in any particular position.
2. I took off the IAC and cleaned out all the gunk with some WD-40 but am still having the same issues. At this point, I'm going to bite the bullet and just buy a new one and see if that fixes the problem.
3. I have heard that many of the aftermarket TB manufacturers sometimes get TB's with the TB blade off round. In turn, when you open and close the blade sometimes it may hang on the ID of the TB and stay slightly open which may be causing part of the hanging idle. Have any of you heard of this? I am also suspect of this issues since a friend of mine that installed a Trickflow plenum/Accufab 75mm TB had the same problem and said he had wrestled with it for a few weeks and couldn't get it to work. He finally gave up and just drove it that way and said that after a couple hundred miles it jsut fixed itself! Do you think that maybe the blade was out of round and that after a couple hundred miles it just self seated?
In my case, in the morning when the car is not to operating temp yet, the hanging idle problem is not as pronounced as when the car gets to op temp(the hang isn't as long when it's cold). Do you think that the off round blade issue gets worse as the TB heats up and the metal expands making the blade against the ID of the TB hang problem worse and therefore hang longer?
Sorry if some of this seems completely off but I'm trying to make heads or tails of this problem since, as I stated earlier, it seems like a lot of guys and gals are running into this problem! I've already gotten other offerings of solutions to the problem but I've tried most of them and they haven't worked. When my friend told me about his experience it seemed to make sense with what I was told about the out of round TB blades!
John
I just got done installing a Trickflow Plenum/75mm TB swap and am having the same issues. I've been doing some investigating and have a few questions/observations for you pros that may help others also.
1. I installed a new TPS on the TB so I don't think I have any issues with the TPS itself although I'm not sure if there is a specific position that the TB blade guide to TPS needs to be in other than closed and you just put the TPS on as is? I assumed that the ECU will self position so there was no need to install it in any particular position.
2. I took off the IAC and cleaned out all the gunk with some WD-40 but am still having the same issues. At this point, I'm going to bite the bullet and just buy a new one and see if that fixes the problem.
3. I have heard that many of the aftermarket TB manufacturers sometimes get TB's with the TB blade off round. In turn, when you open and close the blade sometimes it may hang on the ID of the TB and stay slightly open which may be causing part of the hanging idle. Have any of you heard of this? I am also suspect of this issues since a friend of mine that installed a Trickflow plenum/Accufab 75mm TB had the same problem and said he had wrestled with it for a few weeks and couldn't get it to work. He finally gave up and just drove it that way and said that after a couple hundred miles it jsut fixed itself! Do you think that maybe the blade was out of round and that after a couple hundred miles it just self seated?
In my case, in the morning when the car is not to operating temp yet, the hanging idle problem is not as pronounced as when the car gets to op temp(the hang isn't as long when it's cold). Do you think that the off round blade issue gets worse as the TB heats up and the metal expands making the blade against the ID of the TB hang problem worse and therefore hang longer?
Sorry if some of this seems completely off but I'm trying to make heads or tails of this problem since, as I stated earlier, it seems like a lot of guys and gals are running into this problem! I've already gotten other offerings of solutions to the problem but I've tried most of them and they haven't worked. When my friend told me about his experience it seemed to make sense with what I was told about the out of round TB blades!
John
07-22-2008, 12:49 PM
#3
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RE: Aftermarket TB/Plenum Hanging idle/low idle issues!
YUP!
I spoke to one of the techs over at Galpin Autosports and he told me that this is a common problem with Aftermarket TB/Plenums. He thought it would be best to try and move the TPS around along with replacing the IAC(since it is the one I pulled off the stock plenum). He thought that a tune wouldn't hurt it along with checking to see if, in fact, the TB blade was not shutting all the way. I have a feeling that this may be a big part of the problem sincethe car doesn't hang as long when its cold but the hang is longer when the car reaches op temp. My thinking is that the ID of the TB is heating up and expanding just enough to hang the TB blade. Maybe if I pull it apart and try and smooth the blade a little so that it clears the ID of the TB it'll work better. Not enough to lose the seal but just smooth it a bit so that it closes without hanging. I was also thinking of running a heavier return spring but I'm not surehow that will affect the TPS, whether it'll put a strain on it or not. He also thought that with the MAC LT's the car is probably running a little lean and that with the stock TB/plenum it wasn't a noticeable problem but now that I'm pushing more air through the motor it has exaggerated the problem.
What do you think CliffyK? Does any of this sound plausible?
John
I spoke to one of the techs over at Galpin Autosports and he told me that this is a common problem with Aftermarket TB/Plenums. He thought it would be best to try and move the TPS around along with replacing the IAC(since it is the one I pulled off the stock plenum). He thought that a tune wouldn't hurt it along with checking to see if, in fact, the TB blade was not shutting all the way. I have a feeling that this may be a big part of the problem sincethe car doesn't hang as long when its cold but the hang is longer when the car reaches op temp. My thinking is that the ID of the TB is heating up and expanding just enough to hang the TB blade. Maybe if I pull it apart and try and smooth the blade a little so that it clears the ID of the TB it'll work better. Not enough to lose the seal but just smooth it a bit so that it closes without hanging. I was also thinking of running a heavier return spring but I'm not surehow that will affect the TPS, whether it'll put a strain on it or not. He also thought that with the MAC LT's the car is probably running a little lean and that with the stock TB/plenum it wasn't a noticeable problem but now that I'm pushing more air through the motor it has exaggerated the problem.
What do you think CliffyK? Does any of this sound plausible?
John
07-22-2008, 01:14 PM
#4
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Location: Saint Augustine, FL
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RE: Aftermarket TB/Plenum Hanging idle/low idle issues!
Do not do anything to reshape the butterfly or you will most likely make it worse, it's not supposed to close all the way. [/align][/align]What I would do would be to disconnect the battery, back off very slightly (not more than 1/10th turn) on the stop screw, and not reconnect the battery until it's been disconnected for 5-7 minutes.[/align][/align]Do the TrickFlow instructions not talk about adjusting the stop screw? It's step 9 in the Professional Products installation sheet.[/align][/align]The full process , including re-establishing the base setting is:[/align][/align]Disconnect the battery.[/align][ol][*]Release the locknut and turn the idle screw counter-clockwise until there is light showing between the screw and the throttle linkage lever and the gap between them is 0.010"[*]Turn the screw clockwise 1 turn and tighten the locknut while holding the screw in place;[*]Wait until the battery has been disconnected for 5-7 minutes, then reconnect and start the car;[*]If the idle is still not correct, and too high then back the screw out slightly, and try again; repeat as necessary;[*]If the idle is not correct and too low, or the engine stalls, then turn the screw in slightly, and try again; repeat as necessary;[/ol]
If there is any binding at throttle tip-in then turn the screw in just a tiny bit to eliminate the binding. [/align][/align]Make sure you tighten the locknut, you may want to clear the KAM once more just to make sure things start out clean.[/align][/align]============================[/align]BTW, I have installed thePro Products TB/plenum combo on three carsand have never had any idle problems. The only problem I did have (on all three) was that the keyhole for the throttle cable barrel end was too tight and had to be reamed out a bit.[/align][/align]test[/align]
If there is any binding at throttle tip-in then turn the screw in just a tiny bit to eliminate the binding. [/align][/align]Make sure you tighten the locknut, you may want to clear the KAM once more just to make sure things start out clean.[/align][/align]============================[/align]BTW, I have installed thePro Products TB/plenum combo on three carsand have never had any idle problems. The only problem I did have (on all three) was that the keyhole for the throttle cable barrel end was too tight and had to be reamed out a bit.[/align][/align]test[/align]
08-13-2008, 02:29 AM
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*****UPDATE*****
I was checking all the fittings to make sure I didn't have any leaks and I found the lower screw on the IAC was loose and it wouldn't tighten anymore. I pulled the plenum off to give it a thorough inspection and found that when Trickflow had machined the threading into that bolt hole it wasn't done right and the threading was all screwed up. It looked fine by just looking at it but when you put the supplied screw in the hole it wiggled around like it was too small. I checked the screw against the top IAC screw and they are identical so it wasn't a wrong screw that was provided me in the kit.
I sent the plenum back to Trickflow and they are swapping out another plenum for me.
NOW.......I put the stock plenum back on with the 75mm TB since it would take them a week to get me the new plenum. I had left the battery disconnected for a couple days as I didn't have time to get to the car before I installed the stock plenum. I started the car with the IAC plug off and the car started fine but idled at around 1100 - 1500 rpms. I let it idle without touching the gas for around 1/2 an hour and it settled around 1100 rpms. I plugged the IAC cable back in and there was no difference in idle. I drove the car the first day and it idled around 1100 - 1300 rpms and would hang at around 2000 rpms at decel. I figured I could live with it until I got the new plenum and after I installed it I would get a custom tune done to take care of the idle issue. The second day I drove it the idle dropped to around 700 - 900 rpms and it hangs for a second at around 1100 rpms but it's barely noticeable. I guess it takes the computer a few days to relearn depending on how much you drive. I expect the hang to eventually go away as the computer keeps learning but if it doesn't I may get a hand tuner and try and tune it out. Probably running a little lean with the LT's.
John
I was checking all the fittings to make sure I didn't have any leaks and I found the lower screw on the IAC was loose and it wouldn't tighten anymore. I pulled the plenum off to give it a thorough inspection and found that when Trickflow had machined the threading into that bolt hole it wasn't done right and the threading was all screwed up. It looked fine by just looking at it but when you put the supplied screw in the hole it wiggled around like it was too small. I checked the screw against the top IAC screw and they are identical so it wasn't a wrong screw that was provided me in the kit.
I sent the plenum back to Trickflow and they are swapping out another plenum for me.
NOW.......I put the stock plenum back on with the 75mm TB since it would take them a week to get me the new plenum. I had left the battery disconnected for a couple days as I didn't have time to get to the car before I installed the stock plenum. I started the car with the IAC plug off and the car started fine but idled at around 1100 - 1500 rpms. I let it idle without touching the gas for around 1/2 an hour and it settled around 1100 rpms. I plugged the IAC cable back in and there was no difference in idle. I drove the car the first day and it idled around 1100 - 1300 rpms and would hang at around 2000 rpms at decel. I figured I could live with it until I got the new plenum and after I installed it I would get a custom tune done to take care of the idle issue. The second day I drove it the idle dropped to around 700 - 900 rpms and it hangs for a second at around 1100 rpms but it's barely noticeable. I guess it takes the computer a few days to relearn depending on how much you drive. I expect the hang to eventually go away as the computer keeps learning but if it doesn't I may get a hand tuner and try and tune it out. Probably running a little lean with the LT's.
John
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