Please help with 4 year high idle problem.
Please help with 4 year high idle problem. Ok, I'll try and make this short as possible. Four years ago I put on a ported ls6 manifold with ported 80mm BBK TB. I had high idle and the idle would stay really high when moving till I came to a stop, then it would drop down but still be high. noticed a nice gap at bottom of TB blade and assumed it had been ported to far in and was causing my idle problems. Had the car tuned later on and it wasn't to much better as far as the idle goes.
Just installed LS6 heads and a PP 85mm TB. Car is idling exactly the same.
Checked for leaks with starter fluid, found none.
Adjusted TPS to .67v idle 4.77v WOT
Blade not stuck open
When you crank the car cold it will idle about 1300rpm(by the stock tach) then after a minute or so it bumps itself up to 1400 then couple more minutes up to around 1500 and so on to about 1800rpm. If driving and push in clutch car idles up to 2200rpm till I come to complete stop then idles down to around 1800rpm. I put a piece of tape over the idle hole in blade and it drops it all by about 200-300 rpms. Still very high.
I'm guessing something to do with the IAC values needs to be adjusted. My buddy has HP tuners but he's kinda new to it and I know almost nothing about it. Can anyone help me on what tables and numbers I should be looking for and shooting for. Anything will help. Been living with this problem for a long time and it sucks, my clutch is starting to not like it either since I slip it a lot to keep the idle down when stopping. Was hoping the new TB would solve my problems but no luck, idles eactly like it did before. Thanks everyone.
Just installed LS6 heads and a PP 85mm TB. Car is idling exactly the same.
Checked for leaks with starter fluid, found none.
Adjusted TPS to .67v idle 4.77v WOT
Blade not stuck open
When you crank the car cold it will idle about 1300rpm(by the stock tach) then after a minute or so it bumps itself up to 1400 then couple more minutes up to around 1500 and so on to about 1800rpm. If driving and push in clutch car idles up to 2200rpm till I come to complete stop then idles down to around 1800rpm. I put a piece of tape over the idle hole in blade and it drops it all by about 200-300 rpms. Still very high.
I'm guessing something to do with the IAC values needs to be adjusted. My buddy has HP tuners but he's kinda new to it and I know almost nothing about it. Can anyone help me on what tables and numbers I should be looking for and shooting for. Anything will help. Been living with this problem for a long time and it sucks, my clutch is starting to not like it either since I slip it a lot to keep the idle down when stopping. Was hoping the new TB would solve my problems but no luck, idles eactly like it did before. Thanks everyone.
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
You have a cable TB, is it closing all the way?
Double check all of your vaccum lines, is it sucking air somewhere.
Your TB should be closed so far at idle that you can hardly see light around the blade, if there is more than about .010" gap, it will not idle down.
Double check all of your vaccum lines, is it sucking air somewhere.
Your TB should be closed so far at idle that you can hardly see light around the blade, if there is more than about .010" gap, it will not idle down.
It is closing, blade is vertical and with a light behind it there is just a tiny tiny ring of light around the blade. This is also the exact same idle as it had with a different TB. Checked all vacuum lines, checked around manifold, checked around TB, checked around injectors.
Sounds like your idle air table is off. The warmer the car gets it falls into a different cell. This is why it wants to idle higher and higher as it gets warmer.
Really need a log file to be certain.
Really need a log file to be certain.
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Verdad Gallardo LOL. I told him about the problem and that I thought the throttle body was causing it. He said he did what he could. It was a quick 1 hour dyno tune. So did he change something in there and that is why it is still doing it now with the new TB? I'll try an make it to my friends tomorrow to log some data for you guys, and yes that is exactly what it does, the warmer it gets the higher the idle gets. Crank it in the morning it idles at 1050-1100 until I drive it for a few or it sits for awhile at idle.
And I have checked the back of the manifold, with a flashlight inside the manifold when it was out and with starter fluid while installed.
And I have checked the back of the manifold, with a flashlight inside the manifold when it was out and with starter fluid while installed.
LOL. I told him about the problem and that I thought the throttle body was causing it. He said he did what he could. It was a quick 1 hour dyno tune. So did he change something in there and that is why it is still doing it now with the new TB? I'll try an make it to my friends tomorrow to log some data for you guys, and yes that is exactly what it does, the warmer it gets the higher the idle gets. Crank it in the morning it idles at 1050-1100 until I drive it for a few or it sits for awhile at idle.
And I have checked the back of the manifold, with a flashlight inside the manifold when it was out and with starter fluid while installed.
And I have checked the back of the manifold, with a flashlight inside the manifold when it was out and with starter fluid while installed.
I was actually thinking about ordering a wideband o2 and A/F gauge the other day. Didn't make it to my friends today so no data yet either.
You say to adjust the blade, but this is another T/B which is idling exactly the same as the one I had before. Which I adjusted all over the place to get it to idle the best I could before getting it tuned. Pretty sure the blade position is not my problem.
I'll post up when I get some more data for you guys.. Thanks for the help.
You say to adjust the blade, but this is another T/B which is idling exactly the same as the one I had before. Which I adjusted all over the place to get it to idle the best I could before getting it tuned. Pretty sure the blade position is not my problem.
I'll post up when I get some more data for you guys.. Thanks for the help.
The problem is in the tune, not the adjustment of the throttle blade....although, I know what you mean about some TBs needing adjustment. He stated in an earlier post that the blade was open just enough to see a slight amount of light through it....which sounds correct. Not to mention, it idles fine when cold.....which means that it sounds like the problem is in the tune. Hopefully, he will be able to post a log file here....so that others more "in the know" than myself can give him some guidance based on the info in his scan file.
Do you still have the old parts? If so, swap the old intake and TB and see if it still does it. Maybe your intake is cracked. Also are you running Formato's tune? He should be able to figure this out.
You need to adjust your TPS sensor more. It needs to be around .53 - .55 volts idle. I had mine around .54 then messed with it and it went to .62, and the idle jumped up 400-500rpm. Adjust it down to .53 - .54 and see what happens. Use the little spring assembly with grooves on the throttle cable itself to do your adjustments. If you don't know what I'm talking about, follow the cable up from the TB blade and you'll notice a little black cover that snaps on and off. You can either push it closer and snap back on, or pull away more and snap back on. Doing this will either decrease or increase the position at which the blade is opened at idle.
Also, with a 4.77 reading at WOT, realistically the blade should be opening more than 90 degrees, which would throw a SES code. Are you using the gas pedal to get your reading, or using the blade and doing it by hand? You should be using the gas pedal to get the WOT reading.
Also, if your car is equipped with TCS, check to see if the little green rubber tab is still installed. Take the TCS cover off and look at the bottom little gear thing in the front. There should be a small rubber green tab inserted there. If it is there, leave it.
Let me know if this works for ya, good luck.
INFO HERE
https://ls1tech.com/forums/generatio...g-install.html
Also, with a 4.77 reading at WOT, realistically the blade should be opening more than 90 degrees, which would throw a SES code. Are you using the gas pedal to get your reading, or using the blade and doing it by hand? You should be using the gas pedal to get the WOT reading.
Also, if your car is equipped with TCS, check to see if the little green rubber tab is still installed. Take the TCS cover off and look at the bottom little gear thing in the front. There should be a small rubber green tab inserted there. If it is there, leave it.
Let me know if this works for ya, good luck.
INFO HERE
https://ls1tech.com/forums/generatio...g-install.html
Sorry work has been hell. It'll be a couple weeks before I can get the log.
djfury... Those voltages are way off from anything I have read about the TPS on the LS1. I'll give it a go tho.
Pulse GTO... If the manifold was cracked it would idle high even when started cold because of the un-metered air. Yes I'm still running the same tune but the shop he works at is a long ways from here. When I got it done he was just up this way doing a tune day.
Like I said I am swamped right now "just got home from work and it's 3am, uhhhh" Thanks for the info guys I'll post the log when I find some time. Good to know there are people waiting to help me out though.
djfury... Those voltages are way off from anything I have read about the TPS on the LS1. I'll give it a go tho.
Pulse GTO... If the manifold was cracked it would idle high even when started cold because of the un-metered air. Yes I'm still running the same tune but the shop he works at is a long ways from here. When I got it done he was just up this way doing a tune day.
Like I said I am swamped right now "just got home from work and it's 3am, uhhhh" Thanks for the info guys I'll post the log when I find some time. Good to know there are people waiting to help me out though.
had a similar problem and a buddy of mine fixed something that is attached to the cluch pedal. He told me that it is there to keep the engine idle high so the car wont stall when the clutch is engaged. I am not to fimilar with it but he fixed my issue that I was having when the car was rolling with the clutch ingaged.
Sorry work has been hell. It'll be a couple weeks before I can get the log.
djfury... Those voltages are way off from anything I have read about the TPS on the LS1. I'll give it a go tho.
Pulse GTO... If the manifold was cracked it would idle high even when started cold because of the un-metered air. Yes I'm still running the same tune but the shop he works at is a long ways from here. When I got it done he was just up this way doing a tune day.
Like I said I am swamped right now "just got home from work and it's 3am, uhhhh" Thanks for the info guys I'll post the log when I find some time. Good to know there are people waiting to help me out though.
djfury... Those voltages are way off from anything I have read about the TPS on the LS1. I'll give it a go tho.
Pulse GTO... If the manifold was cracked it would idle high even when started cold because of the un-metered air. Yes I'm still running the same tune but the shop he works at is a long ways from here. When I got it done he was just up this way doing a tune day.
Like I said I am swamped right now "just got home from work and it's 3am, uhhhh" Thanks for the info guys I'll post the log when I find some time. Good to know there are people waiting to help me out though.
