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Uneven LTFTs Because of Y-pipe?

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Old Jan 2, 2007 | 11:41 PM
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Default Uneven LTFTs Because of Y-pipe?

I have a 408 stroker that I just put in my 98. I have the Kooks 1 7/8 long tubes and their y-pipe with cats. My LTs on bank 1 are zero at idle and on bank 2 are +4 generally. I have of course looked for any other problems. Exhaust leaks and such. Would this be considered normal or do I have something wrong? Thanks for any help.
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Old Jan 2, 2007 | 11:57 PM
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have you reset your trims after the install? (if you have tuning software do this)
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Old Jan 3, 2007 | 12:26 AM
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Are they new 02s? They develope drift over time....
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Old Jan 3, 2007 | 12:38 AM
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If the difference is only at idle then I wouldn’t worry about it. That much average difference under load might indicate an injector problem.
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Old Jan 3, 2007 | 01:06 AM
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I have put about 500 miles on the motor so far. I have not reset the LTFTs but would this not have been enough time already. I have brand new vette rear O2s. The difference in LTFTs is there under light load as well. I have the 42lbs injectors and they were used but I tested them and all have around 15 ohms. I also have an injector coil tester and they all passed. They guy at my shop who tuned my car is too busy to help me much more with the tune. We have HP Tuner but it is not mine. I bought a $100 license. I need to get my own. Which one would you guys go with right now? EFI Live or HP. I have a 98 so I can't use all the newer features. Who has the best price? I would like to get it with a wideband combo.

Last edited by 16floz470ml; Jan 3, 2007 at 01:44 AM.
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Old Jan 3, 2007 | 07:34 AM
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EFILive would probably work best for you (Unlimited 97/98's) and you can get a good package deal from www.greenlightmotorpsports.com.

As far as the uneven readings, double check your intake manifold for leaks. You can do this using a can of starter fluid and spraying around the manifold. Because your drift is not that bad, it may be hard to identify the leaking area. Will definately help to monitor your STFT's and O2 voltage on a scan tool while you're leak checking.

Also, double check for exhaust leaks. A can of SeaFoam makes this very easy. Follow the directions on the can, then when you start it up and it's smoking like mad, have a look around your exhuast plumbing. If smoke is coming out anywhere but the tail pipes, you've found a leak.
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Old Jan 3, 2007 | 11:19 PM
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Today I replaced all the intake gaskets with my extra set. Still no change in the LTFT. The first few times I put the intake on it would not go flush without some extra effort. I have an ls6 intake. You kind of had to pop it on in the last corner. I have new style block offs and knock sensor harness. Now after having it on and off a few times it goes right on. I wonder if somehow this could be my problem. On the exhaust side I have another set of exhaust gaskets I will try. That seafoam sounds pretty good too.
So on Green Light Motorsports you can get the V2 + LC1 for $900. Is this a good deal? Am I understanding correctly that this is a standalone and no laptap is needed? Am I going to need memory cards and such?
The tune in my car is HPT, I have HPT software to learn on and have a laptop. I may just get my own cable. Is $399 the best price I can get? Anybody know of any HPT Wide band combos? Thanks for any help.
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