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Old 01-19-2019, 08:14 AM   #1
RavensFan7
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Default Per cylinder comps, what cylinders are A/B/C/D?

Read all the threads I could find. Still no 100% answer on which cylinders a/b/c/d actually are. Seems like most agree that A=1 and D=4, just not sure about the other 2. Anyone ever figure this out?

Youd think A-D would be cylinders 1-4 (A=1 B=2 C=3 D=4)

but some people think it might be firing order, A=1 B=3 C=2 D=4
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Old 01-19-2019, 01:15 PM   #2
JSR84
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What vehicle, year and what software?

Last edited by JSR84; 01-19-2019 at 02:04 PM.
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Old 01-19-2019, 04:43 PM   #3
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Ecu is 02/03 wrx using accesstuner
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Old 01-19-2019, 05:39 PM   #4
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Are you talking about AF learning A B C D?
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Old 01-19-2019, 06:08 PM   #5
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Quote:
Originally Posted by JSR84 View Post
Are you talking about AF learning A B C D?

No, the per cylinder compensations for fuel and timing. The tables are A/B/C/D and no one seems to know what cylinders the letters refer to. Its either A/B/C/D equals 1/2/3/4, or 1/3/2/4
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Old 01-19-2019, 06:50 PM   #6
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Most be different in the 16 bit ECU's. Mine are just labled 1 2 3 4.


Good luck
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Old 01-19-2019, 08:03 PM   #7
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it would make sense that it would be ABCD would be 1234 but you never know with these things when the speed of the code running matters... they very well could be firing order.

but the fact that A&C often have the same compensations, and B&D have the same comps ( but different from A&C) makes me thing they are 1234 because each bank would need different comps.
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Old 01-19-2019, 10:17 PM   #8
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Can you test it? Set your misfire detection threshold really low and pull like 10* of timing and a bunch of fuel from A and see where the miss shows up?
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Old 01-20-2019, 12:05 AM   #9
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keep in mind if you pull fuel from some cylinders the others will run rich in closed loop. there was a guy on here who said they read the spark plugs and figured out which cylinders were which letter. but never shared the findings... if you had EGT on each cylinder you could pull timing and see which one heats up.
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Old 01-20-2019, 08:33 AM   #10
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Quote:
Originally Posted by CarmelValleyWRX View Post
it would make sense that it would be ABCD would be 1234 but you never know with these things when the speed of the code running matters... they very well could be firing order.

but the fact that A&C often have the same compensations, and B&D have the same comps ( but different from A&C) makes me thing they are 1234 because each bank would need different comps.

Mine are paired differently for 02/03 which kinda adds to the confusion. Fuel uses A&C and B&D, and timing uses A&B and C&D

Timing:
-2.11 for A and B
0.00 for C and D

Fuel:
-0.0300 for A and C
0.0300 for B and D

Quote:
Originally Posted by 86Dreams View Post
Can you test it? Set your misfire detection threshold really low and pull like 10* of timing and a bunch of fuel from A and see where the miss shows up?

Hmm that might be a decent way to test it without 4 channel egt stuff
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Old 02-22-2019, 12:29 AM   #11
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You can force open loop fueling to keep the closed loop behavior from interfering in the test 86 dreams suggested.

Couldn't you also unplug one injector at a time and watch the misfire count? Actually, if the injector has low voltage you should get a code that specifically names the problem cylinder. I know becuase I had a plug adapter that was hanging by a couple strands of wire. Not sure if unplugging would have the same error though. Worth a shot.

What about raising timing on each cylinder until the car knocks, then look at the logged knock sum to see what cylinder has the increase?
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