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Patch request discussion: rev-down maf clamp (stalling issue)

 
Old Aug 11, 2011, 05:58 PM
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Originally Posted by shadow1 View Post
I never found a solution to the idle stumble with Tephra. Switching back to my tuned stock rom completely eliminated all idle stumble.
What was your stock ROM and what TephraRom? Is it 96940011 and 96530006?

Some people seem to be having the issue because of the ISCV tables. If you are using a Tephra version ROM that isn't your stock ROM, maybe try matching the ISCV tables back up (or at least comparing them)...all of the tables that are mentioned in mrfred ISCV disassembly.

Also, just for mention, if it is 9694-->9653, back when I coverted way back when, the ISCV tables weren't found yet. But, idle was a known issue for that conversion where the BISS needed to be set properly. Not sure if you tried that or not.

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Old Aug 12, 2011, 07:57 AM
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Originally Posted by Dynotech Tuning View Post
Post a log of your car stumbling at idle during decel. DataLog the following: Timing, Airflow HZ, RPM and Load. I will see if I can't help out. The key is to find the engine load your car is seeing during the 'stumble'. It will most likely be between 60-90 load, around 500-1000 rpm.


-Jamie
I will do this tomorrow and pm you a log. Thanks SO MUCH for your help.



Originally Posted by shadow1 View Post
I never found a solution to the idle stumble with Tephra. Switching back to my tuned stock rom completely eliminated all idle stumble.
Which is the MAIN reason why this is so irritating...... I'm on a stock rom but having the same **** issue.
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Old Aug 12, 2011, 08:21 AM
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Originally Posted by l2r99gst View Post
What was your stock ROM and what TephraRom? Is it 96940011 and 96530006?

Some people seem to be having the issue because of the ISCV tables. If you are using a Tephra version ROM that isn't your stock ROM, maybe try matching the ISCV tables back up (or at least comparing them)...all of the tables that are mentioned in mrfred ISCV disassembly.

Also, just for mention, if it is 9694-->9653, back when I coverted way back when, the ISCV tables weren't found yet. But, idle was a known issue for that conversion where the BISS needed to be set properly. Not sure if you tried that or not.
I experimented with 96530706 and 94170715 for months. I tried everything from BISS adjustment to playing with ISCV tables. Btw most of the ISCV tables are mislabeled in 96940011 and 94170015. Mr Fred figured it all out for 9653 and for the IX rom. I ended up switching back to 96940011 with the same tune as my Tephra rom and my idle was back to being perfect. The part throttle then clutch in stumble was both aggravating and embarrassing (stalling while pulling into a car meet).
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Old Aug 12, 2011, 08:25 AM
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Originally Posted by shadow1 View Post
I experimented with 96530706 and 94170715 for months. I tried everything from BISS adjustment to playing with ISCV tables. Btw most of the ISCV tables are mislabeled in 96940011 and 94170015. Mr Fred figured it all out for 9653 and for the IX rom. I ended up switching back to 96940011 with the same tune as my Tephra rom and my idle was back to being perfect. The part throttle then clutch in stumble was both aggravating and embarrassing (stalling while pulling into a car meet).
I just cannot for the life of me figure out why my STOCK rom is having these same issues, and they only started after I replaced my hks 272's with Kelfords, swapped out to my new turbo, and the injectors. And yes, my injectors are scaled properly I BELIEVE ANYWAY as my LTFT high, mid, and low are all withing +-2

The only other thing I notice is now, when I turn on my lights, my idle drops about 100rpm, and if I turn on my second set of low lights, it drops another 100rpm. Could this be latency issues on the injectors, or is this the norm?
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Old Aug 12, 2011, 09:28 AM
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Have you pressure tested your intake tract to rule out any boost leaks?
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Old Aug 12, 2011, 10:02 AM
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Originally Posted by shadow1 View Post
Have you pressure tested your intake tract to rule out any boost leaks?
Done directly after install. Boost holds steady 29psi tapered to 27psi close to redline.
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Old Aug 12, 2011, 11:15 AM
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You can't pressure test by driving the car and looking at the boost gauge. Pressure testing involves removing the intake pipe and capping the turbo inlet with a pressure tester. You then use compressed air to pressure the entire intake tract while listening for leaks. Leaks are common on Evos.
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Old Aug 12, 2011, 11:53 AM
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Originally Posted by shadow1 View Post
I experimented with 96530706 and 94170715 for months. I tried everything from BISS adjustment to playing with ISCV tables. Btw most of the ISCV tables are mislabeled in 96940011 and 94170015. Mr Fred figured it all out for 9653 and for the IX rom. I ended up switching back to 96940011 with the same tune as my Tephra rom and my idle was back to being perfect. The part throttle then clutch in stumble was both aggravating and embarrassing (stalling while pulling into a car meet).
I added all the of 9694 tables to mrfred's iscv thread a while back.
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Old Aug 12, 2011, 12:22 PM
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I meant to say that the older ISCV AC on, AC off, neutral and drive tables were wrong. The disassembly tables are the correct ones. I have the 9694 tables. The 9417 tables are incomplete.
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Old Aug 13, 2011, 02:04 PM
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Originally Posted by shadow1 View Post
You can't pressure test by driving the car and looking at the boost gauge. Pressure testing involves removing the intake pipe and capping the turbo inlet with a pressure tester. You then use compressed air to pressure the entire intake tract while listening for leaks. Leaks are common on Evos.
LOL... no

I meant I have done a boost leak test with the little device I made off of a how to here. No leaks. Just meant my car is holding boost strong.
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Old Aug 28, 2011, 03:39 AM
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just go to iscv demand target idle trim and bump up the the percentages of the first 4 rows to 1.6 % or whatever that works for you.Then you should bump up the last two cells of the iscv demand cts adder table, you can find which one is ac off neutral and drive they are listed in the iscv disassembly thread ( the old iscv demand tables under idle are wrong so you should use the new iscv control tables) And you should log iscv demand in evoscan and see how much your iscv demand is at normal idle and how much it is increasing to compensate for the rpm drop and to get it back to idle normal again and at idle your isc steps should be between 2-25 so play with the iscv demand cts adder tables to get it to idle between 2-25 mine is about 19 at neutral with ac off. That's what worked for me i am using the 96530706 rom and i have kelford 272's and i was experiencing idle drop and the car would stall when i would get to a red light. i hope this will fix your problem
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