Help! Chasing tail with VE tune!
Thread Starter
Joined: May 2003
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From: Fairfax County, VA (You know you're here when you see the bad roads)
Help! Chasing tail with VE tune! So Im having a bit of trouble tuning my VE table. I have set my configs up as specified in the pdf from thetuningguide.com to tune for VE. I am chasing my tail with the tune...every time I scan and tune my ve table goes up by 10% or so. So I copy and past the new ve table, scan again...10% more. Now my VE table is well over 110% on some parts which cant be right???
What am I missing?
Thanks for the help!
*edit* re-uploaded files
What am I missing?
Thanks for the help!
*edit* re-uploaded files
Last edited by UMD_Jesse; Sep 8, 2012 at 06:27 AM.
Thread Starter
Joined: May 2003
Posts: 377
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From: Fairfax County, VA (You know you're here when you see the bad roads)
From reading this thread:
https://ls1tech.com/forums/pcm-diagn...ne-inside.html
Is it possible that the source of my troubles are that my OL&CL > EQ Ratio and my Power Enrich > EQ Ration v RPM dont match?
Can someone please confirm this?
https://ls1tech.com/forums/pcm-diagn...ne-inside.html
Is it possible that the source of my troubles are that my OL&CL > EQ Ratio and my Power Enrich > EQ Ration v RPM dont match?
Can someone please confirm this?
You need to check how did you failed the MAF in the tune.
I can't see the tune here, but if the MAF is properly failed the PCM will use the secondary VE table, so you need to modify both VE tables every time you datalog.
IF you only modify the primary VE table, or didn't properly fail the MAF, that may be your problem.
I can't see the tune here, but if the MAF is properly failed the PCM will use the secondary VE table, so you need to modify both VE tables every time you datalog.
IF you only modify the primary VE table, or didn't properly fail the MAF, that may be your problem.
Thread Starter
Joined: May 2003
Posts: 377
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From: Fairfax County, VA (You know you're here when you see the bad roads)
Hmmm....Well, let me just try to unplug the SOB and see how that works? Ill give it a shot today and report back. Thanks for the replies folks
I just looked quickly, most likely the MAF is still being referenced. The SES is still enabled, High RPM disable is @ 4000 rpm, MAF table is loaded.
Those three things should be done to insure the MAF is disabled, the OP did set MAF fail Hi to "0". That is suppose to work, my experience trying it is "no".
Those three things should be done to insure the MAF is disabled, the OP did set MAF fail Hi to "0". That is suppose to work, my experience trying it is "no".
Thread Starter
Joined: May 2003
Posts: 377
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From: Fairfax County, VA (You know you're here when you see the bad roads)
You need to check how did you failed the MAF in the tune.
I can't see the tune here, but if the MAF is properly failed the PCM will use the secondary VE table, so you need to modify both VE tables every time you datalog.
IF you only modify the primary VE table, or didn't properly fail the MAF, that may be your problem.
I can't see the tune here, but if the MAF is properly failed the PCM will use the secondary VE table, so you need to modify both VE tables every time you datalog.
IF you only modify the primary VE table, or didn't properly fail the MAF, that may be your problem.
Last edited by UMD_Jesse; Sep 8, 2012 at 04:19 PM.
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From: Ann Arbor, MI
Just to be sure, I also disconnect the MAF when performing a VE tune.
Correct, a 1998 PCM has two VE tables and the second one is used for No-MAF (SD) operation. However a 2001 PCM has only one VE table and must therefore be used for both MAF and No-MAF operation.
Correct, a 1998 PCM has two VE tables and the second one is used for No-MAF (SD) operation. However a 2001 PCM has only one VE table and must therefore be used for both MAF and No-MAF operation.
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If you are tuning with a wideband did you turn the fuel trims off and reset them? The other thing to pay close attention to is the intake air temp. The sensor heat soaks when you stop to load in a new tune and it will run lean until that gets back to a normal reading. I usually open the hood to cool things down when making changes and then drive around until the temp is close to what it was reading in the previous log. Then you need to get enough hits in all the cells and filter the closed throttle decel data which scews your readings.
Thread Starter
Joined: May 2003
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From: Fairfax County, VA (You know you're here when you see the bad roads)
If you are tuning with a wideband did you turn the fuel trims off and reset them? The other thing to pay close attention to is the intake air temp. The sensor heat soaks when you stop to load in a new tune and it will run lean until that gets back to a normal reading. I usually open the hood to cool things down when making changes and then drive around until the temp is close to what it was reading in the previous log. Then you need to get enough hits in all the cells and filter the closed throttle decel data which scews your readings.
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Havig a little trouble with my sons 2002 CS,Ls1 motor had a blown head gasket on the right side of the motor between 6-8 cly,repalced both head gaskets.Leaking oil pan gasket droped oil pan and replaced the gasket, cranked the moter and set the lifters when the car is running,problem, we still here something rattling on the left side of the motor next to the fire wall,could be lifters.I tightened them down,then 1/4 turn.It has headers,but there not leading,sounds like two pipes rubbing together,no vacm,leaks in the back..im getting to old for this,Thanks for your help,hope i can find this page again
Thread Starter
Joined: May 2003
Posts: 377
Likes: 0
From: Fairfax County, VA (You know you're here when you see the bad roads)
Havig a little trouble with my sons 2002 CS,Ls1 motor had a blown head gasket on the right side of the motor between 6-8 cly,repalced both head gaskets.Leaking oil pan gasket droped oil pan and replaced the gasket, cranked the moter and set the lifters when the car is running,problem, we still here something rattling on the left side of the motor next to the fire wall,could be lifters.I tightened them down,then 1/4 turn.It has headers,but there not leading,sounds like two pipes rubbing together,no vacm,leaks in the back..im getting to old for this,Thanks for your help,hope i can find this page again
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From: Ann Arbor, MI
Dgrass: You incorrectly posted in the middle of an unrelated thread.
Instead, you should go to the list of forums, select the most related forum and then press the [New Thread] button in the upper left hand corner.
Instead, you should go to the list of forums, select the most related forum and then press the [New Thread] button in the upper left hand corner.
Can you elaborate on the heat soak idea??? That sounds like it may be a possible issue because when I start tuning everything is off, but the more I drive and hit each cell, the more everything seems to normalize, but mostly it normalizes in the cruising rpm cells, the mediums and extreams are consistantly way off
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From: Ann Arbor, MI
The heat soak issue drove me so crazy that I finally extended the wires to mount the IAT just behind the headlight, far away from engine heat.
Not sure if this is normal, but I temporarily get huge AFR errors when I punch the throttle or snap it shut. Therefore, to get a good AFR Error Histogram, I ease into and out of the throttle. Even then I can tell that a few cells are simply off and I fix it by hand-smoothing the VE table.
To set the WOT values, I chart the AFR error, look for steady errors and then hand-adjust the MAP's 95 and 100 values; this is best done at the track to keep things safe and legal.
Not sure if this is normal, but I temporarily get huge AFR errors when I punch the throttle or snap it shut. Therefore, to get a good AFR Error Histogram, I ease into and out of the throttle. Even then I can tell that a few cells are simply off and I fix it by hand-smoothing the VE table.
To set the WOT values, I chart the AFR error, look for steady errors and then hand-adjust the MAP's 95 and 100 values; this is best done at the track to keep things safe and legal.
Your not in SD mode, you need to set the P0103 code to 2-no mil. The PCM has to see a Maf code in order to go into SD mode.
Also set the open loop table to 1.00 at operating temps.
Russ Kemp
Also set the open loop table to 1.00 at operating temps.
Russ Kemp
I believe the 2002 f-body PCMs do NOT have secondary VE tables, right??? The MAF is definitley failed, but I still cant seem to get my AFR error/VE PID to within +/- 1-2 for the values. Im consitantly getting errors values of 5, 6, 7 or higher. The cruise cells, (i.e. light load in the 1200-2200 rpm range) seem ok , but the other cells are all over.
Still, you need to check if the MAF is truly failed or not, open the scanner and you should see a MF code
Thread Starter
Joined: May 2003
Posts: 377
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From: Fairfax County, VA (You know you're here when you see the bad roads)
Well, the heat soak sounds like it was probobly the cause. I was able to get the VE table tuning to show consistent result by only logging on the highway while moving and using the brake to increase load. Once completed, by VE table scans are now much closer to the 1-2 range under all driving conditions. So I think I have this solved and will move on the the MAF now. Thanks for the help!
Thanks again, I also did the extra steps from the thread to make sure the MAF was failed
Thanks again, I also did the extra steps from the thread to make sure the MAF was failed
