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Old 09-14-2004, 09:39 PM   #1
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Default ECM Secrets & Tuning Hints

I found an interesting site that explains pretty well some of the scantool parameters. For instance, item 3 talks about the BLM. Normally, this should always be around 128. A higher number indicates the ECM is detecting a lean condition and adds more fuel.

I found on my car that by removing my MAF screen, the BLM ran up to 159 and stayed there, so it looks as if it detected a lean condition. Item 14 talks about the MAF screen, and recommends leaving it on. Now I can see why. Any comments?

http://www.ag.auburn.edu/users/gparm...al_hints.htm#3
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Old 09-14-2004, 10:25 PM   #2
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Very interesting find, good job! I'm still reading it right now but as far as the scantool readings the ST and LT fuel trims are where to look for the 128 number. LT being long term fuel trim, and ST being short term. LT is the average, but ST you can watch change as you drive.
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Old 09-14-2004, 10:32 PM   #3
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"we currently have in development a system to measure airflow indirectly, allowing the majority of the air to bypass the MAF, much like the Hitachi sensors used in the 3800 Series II engines." uhm...thats us. Wonder what the details are
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Old 09-14-2004, 10:35 PM   #4
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Quote:
Originally Posted by DrJay
"we currently have in development a system to measure airflow indirectly, allowing the majority of the air to bypass the MAF, much like the Hitachi sensors used in the 3800 Series II engines." uhm...thats us. Wonder what the details are
That'* the park the piqued my intrest.. The MAF and TB say Hitachi right in them....
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Old 09-14-2004, 10:55 PM   #5
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so about the maf screen... they recommended keeping it in for their turbo buick setups, but notice what they say regarding the 3800 Ser. II:

Quote:
For those of you in that league, we currently have in development a system to measure airflow indirectly, allowing the majority of the air to bypass the MAF, much like the Hitachi sensors used in the 3800 Series II engines. Look for an upcoming announcement, hopefully in the near future.
This seems to indicate that series II guys have a maf that is capable of being run without a maf screen?
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Old 09-14-2004, 10:56 PM   #6
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lol sorry i posted that before refreshing....
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Old 09-14-2004, 11:28 PM   #7
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I know with mine, the idle was a little rough for part of the first day after removing the screen, but the throttle response seemed to be improved. My PCM learned what it needed to settle the idle back down.

This may differ between OBD1 and OBD2 in how long it takes. Before the smooth-walled intake, my idle wouldn't settle down at all with the screen out, but I know some Series 2 cars would.
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Old 09-14-2004, 11:34 PM   #8
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I'm still sketchy about pulling the MAF screen on my S2 L67. So many top performers still have it in.
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Old 09-15-2004, 12:11 AM   #9
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its a minimal gain. Kyle, you might want to try it since you are SC, and you pull quite a bit of air. Its pretty easy to take in and out. Just make sure the car is cooled off.
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Old 09-15-2004, 12:46 AM   #10
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I'm pretty sure Kyle ran with it off on the Red Rocket for some time.
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