Individual cylinder fuel trim ?? LT1
07-11-2010, 09:27 PM
#1
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Individual cylinder fuel trim ?? LT1 Can the PCM adjust or change the values in the Individual Cylinder Fuel trim tables? or is it a fixed reference point?
The reason I ask is because I have recently started to try tuning myself and am just learning the software before I try to make any changes. But while looking at my tables I noticed that for instance the Idle ICFT table has different tables values for each cylinder
for instance:
EDITED to help reduce confusion
The bin file I have from this pcm has these values as:
1.06
0.95
0.95
1.00
0.98
0.95
0.94
1.08
for Idle
and...
1.03
0.98
1.02
1.02
0.99
0.97
0.98
1.02
off idle
why are they different?
The reason I ask is because I have recently started to try tuning myself and am just learning the software before I try to make any changes. But while looking at my tables I noticed that for instance the Idle ICFT table has different tables values for each cylinder
for instance:
EDITED to help reduce confusion
The bin file I have from this pcm has these values as:
1.06
0.95
0.95
1.00
0.98
0.95
0.94
1.08
for Idle
and...
1.03
0.98
1.02
1.02
0.99
0.97
0.98
1.02
off idle
why are they different?
Last edited by Raven97; 07-12-2010 at 04:01 PM. Reason: Partially answered my own question...
07-12-2010, 03:59 PM
#4
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This is a OBD1 LT1. I think when I was playing with the program trying to get familiar with it I figured out what was up with the first two sets of numbers, I had been looking at a data log session that I did and somehow it was pulling the screwy numers from that and not the .Bin file.
However; I still am wondering about the second set of values, Shouldn't they be all equal for a base tune? aren't these tables constants? OR can the PCM adust these values over time? This is a mail order tune.
However; I still am wondering about the second set of values, Shouldn't they be all equal for a base tune? aren't these tables constants? OR can the PCM adust these values over time? This is a mail order tune.
07-12-2010, 04:28 PM
#5
This is a OBD1 LT1. I think when I was playing with the program trying to get familiar with it I figured out what was up with the first two sets of numbers, I had been looking at a data log session that I did and somehow it was pulling the screwy numers from that and not the .Bin file.
However; I still am wondering about the second set of values, Shouldn't they be all equal for a base tune? aren't these tables constants? OR can the PCM adust these values over time? This is a mail order tune.
However; I still am wondering about the second set of values, Shouldn't they be all equal for a base tune? aren't these tables constants? OR can the PCM adust these values over time? This is a mail order tune.
07-12-2010, 04:44 PM
#6
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Ok that is what I thought, So why wouldn't the individual fuel trims all be equal for a baseline tune? wouldn't they be the same and then you make adjustments from there?
I understand they should be tuned very carefully such as with individual EGT sensors in each header primary.
Thanks for helping a beginner!
I understand they should be tuned very carefully such as with individual EGT sensors in each header primary.
Thanks for helping a beginner!
07-13-2010, 08:43 AM
#7
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No, I believe they're different because each cylinder reacts different based on the design of the intake manifold from the factory. those are the numbers already in the tune for that specific reason.
