LS7 % TPS at idle
02-27-2007, 04:07 PM
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LS7 % TPS at idle We are struggling to get our LS7 to idle with a stock engine and Katech camshaft. With the TPS at 9% it is constantly stalling. I can drill the throttle blade and play with the idle decay etc.
What I need to know is where is the stock engine TPS at idle? I can crank open the idle stop but I could get beyond where the IAC is effective and create a new problem. We are using a UMI throttle body.
What I need to know is where is the stock engine TPS at idle? I can crank open the idle stop but I could get beyond where the IAC is effective and create a new problem. We are using a UMI throttle body.
02-27-2007, 04:42 PM
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Still new to EFI tuning so I may need a translation. I can manipulate when the IAC starts and stops based on % throttle. However the IAC is going to become ineffective (I think) as the throttle becomes more open.
I have no idea what you mean in the second part. Can you clarify?
I have no idea what you mean in the second part. Can you clarify?
02-27-2007, 04:51 PM
#4
There are two tables in the tune fine by the numbers below (EFILive anyway)
One sets the engine displacement by cyl volume which should be 875 cc and the other is the TB dia calculation which should be .0157 for a 90 mm tb.
If you still have the old values in there it will hell.
One sets the engine displacement by cyl volume which should be 875 cc and the other is the TB dia calculation which should be .0157 for a 90 mm tb.
If you still have the old values in there it will hell.
02-27-2007, 05:43 PM
#5
Originally Posted by pcf_mark
We are struggling to get our LS7 to idle with a stock engine and Katech camshaft. With the TPS at 9% it is constantly stalling. I can drill the throttle blade and play with the idle decay etc.
What I need to know is where is the stock engine TPS at idle? I can crank open the idle stop but I could get beyond where the IAC is effective and create a new problem. We are using a UMI throttle body.
What I need to know is where is the stock engine TPS at idle? I can crank open the idle stop but I could get beyond where the IAC is effective and create a new problem. We are using a UMI throttle body.
03-01-2007, 07:57 PM
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Yes I am tuning it myself. I have a baseline tune for a stock LS7 but it is either not too agreable with the Katech stick or is just plain wrong. The BigStuff is easy enough to use and navigate. I was hoping I did not need to drill the throttle blade as it seems like the big stick method. I have plenty of vacuum so I am not dealing with some crazy camshaft profile freaking out the MAP. Decent timing but I can not get it to stabilize at idle long enough to really work with it. It seems like I can crack open the throttle stop to get me close but I am afraid of going too far and getting beyond what the IAC can handle.
03-01-2007, 09:38 PM
#7
Originally Posted by pcf_mark
Yes I am tuning it myself. I have a baseline tune for a stock LS7 but it is either not too agreable with the Katech stick or is just plain wrong. The BigStuff is easy enough to use and navigate. I was hoping I did not need to drill the throttle blade as it seems like the big stick method. I have plenty of vacuum so I am not dealing with some crazy camshaft profile freaking out the MAP. Decent timing but I can not get it to stabilize at idle long enough to really work with it. It seems like I can crack open the throttle stop to get me close but I am afraid of going too far and getting beyond what the IAC can handle.
