Difference between Short Term / Long Term Fuel Trim
Thread Starter
Intermediate
Joined: Feb 2002
Posts: 25
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From: Carrollton TX
Difference between Short Term / Long Term Fuel Trim
I am using datamaster software on my 1991 L-98. I am trying to understand the difference between Short Term / Long Term Fuel Trim. Which is a better indication of the AIR/FUEL ratio? It seems one shows LEAN and the other RICH. What gives? :confused:
Short Term Fuel Trim (STerm)
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Formally called the Integrator, this is the short term fuel correction factor that the PCM is using.
Long Term Fuel Trim (LTerm)
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Formally called the Block Learn Mode (BLM), this is the long term fuel correction factor that the PCM is using.
[Modified by capkwk, 2:18 PM 8/26/2002]
Short Term Fuel Trim (STerm)
------------------------------------
Formally called the Integrator, this is the short term fuel correction factor that the PCM is using.
Long Term Fuel Trim (LTerm)
-----------------------------------
Formally called the Block Learn Mode (BLM), this is the long term fuel correction factor that the PCM is using.
[Modified by capkwk, 2:18 PM 8/26/2002]
Drifting
Joined: Mar 1999
Posts: 1,931
Likes: 1
From: Norcross GA
Re: Difference between Short Term / Long Term Fuel Trim (capkwk)
In a nutshell, the ECM used the BLM #'s to calculate the injector pulse width. There are a few BLM's that are used. Diff ones for diff modes.
Nutshell, the INT is what the O2 sensor is seeing righ now. These values are used to update the BLM's.
Think of it like, INT= average of O2 over time. BLM= average of INT over time.
Nutshell, the INT is what the O2 sensor is seeing righ now. These values are used to update the BLM's.
Think of it like, INT= average of O2 over time. BLM= average of INT over time.
