Clarify a BLM question for me please
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Clarify a BLM question for me please
If the BLM's are low does that mean:
A. The engine is running lean and it's having to add fuel to compensate
B. The engine is running rich and it's pulling fuel
I use data master for data logging and here's my question. When the BLM's are low it turns red, when high it turns green. This would point me in the direction of point A. Meaning that over the long term it has to add fuel to keep the proper A/F ratio, this is a bad thing, hence red. If it's green it's actually running rich and it's having to pull fuel which is OK because it can always add more if needed.
I do have a reason for asking, we'll get to that later
A. The engine is running lean and it's having to add fuel to compensate
B. The engine is running rich and it's pulling fuel
I use data master for data logging and here's my question. When the BLM's are low it turns red, when high it turns green. This would point me in the direction of point A. Meaning that over the long term it has to add fuel to keep the proper A/F ratio, this is a bad thing, hence red. If it's green it's actually running rich and it's having to pull fuel which is OK because it can always add more if needed.
I do have a reason for asking, we'll get to that later
Le Mans Master
Joined: Sep 2001
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From: More cowbell...
St. Jude Donor '04
Re: Clarify a BLM question for me please (Nathan Plemons)
Nathan-
It is actually the other way around. The BLM is the short term ammount of fuel that needs to be added/subtracted in order to achieve a 14.7, with 128 being zero. Thus, anything below 128, indicates that fuel is being taken away, so you have a rich running condition. Anything above, indicates that fuel is being added, thus you have a lean condition.
Read the sixth post of this thread.
Hope that helps.
[Modified by MarkLT1, 9:57 AM 4/13/2003]
It is actually the other way around. The BLM is the short term ammount of fuel that needs to be added/subtracted in order to achieve a 14.7, with 128 being zero. Thus, anything below 128, indicates that fuel is being taken away, so you have a rich running condition. Anything above, indicates that fuel is being added, thus you have a lean condition.
Read the sixth post of this thread.
Hope that helps.
[Modified by MarkLT1, 9:57 AM 4/13/2003]
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From: Sun City West Az
Re: Clarify a BLM question for me please (MarkLT1)
:iagree: ...The only thing wrong with the above post is that the BLM's are a LONG term fuel correction made by the ECM. This is a direct resut of the intergrators (SHORT term fuel correcton) staying above or below the 128 netural value (14:7:1). BLM numbers below 128 indicate fuel delivery to rich so the ECM is decreasing pulse width to reduce fuel delivery.
Thread Starter
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Re: Clarify a BLM question for me please (MarkLT1)
A friend of mine was having some issues with his car at the track last night. I never gave it a thought to take my laptop but I had data logged the car before. The long term trims were around 120 when I logged it.
I was trying to figure out if his issues were spark or fuel related. If low numbers mean he's actually running rich than I guess we'll pursue spark. It felt like a miss anyway.
The car would launch alright and then around 4000-4500 rpm's it almost felt like it was hitting the rev limiter. Eventually it would blast through it and run OK until you got into the next gear. It also seemed to do it worse in 1st and 2nd than it did in 3rd. (kinda why I thought it might be fuel related)
At this point it could be anything from fuel to the opti. The car has 98k miles on it and probably has original plugs and wires with the original opti and the original fuel filter. We're gonna start with new MSD wires, new plugs and a fuel filter and go from there.
I was trying to figure out if his issues were spark or fuel related. If low numbers mean he's actually running rich than I guess we'll pursue spark. It felt like a miss anyway.
The car would launch alright and then around 4000-4500 rpm's it almost felt like it was hitting the rev limiter. Eventually it would blast through it and run OK until you got into the next gear. It also seemed to do it worse in 1st and 2nd than it did in 3rd. (kinda why I thought it might be fuel related)
At this point it could be anything from fuel to the opti. The car has 98k miles on it and probably has original plugs and wires with the original opti and the original fuel filter. We're gonna start with new MSD wires, new plugs and a fuel filter and go from there.
Le Mans Master
Joined: Sep 2001
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From: More cowbell...
St. Jude Donor '04
Re: Clarify a BLM question for me please (ittlfly)
:iagree: ...The only thing wrong with the above post is that the BLM's are a LONG term fuel correction made by the ECM.
MarkLT1 in the morning :sleep: :sleep: :crazy:
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: Clarify a BLM question for me please (MarkLT1)
:iagree: ...The only thing wrong with the above post is that the BLM's are a LONG term fuel correction made by the ECM.
Doh!! I should have my posting rights taken away before 10am..
MarkLT1 in the morning :sleep: :sleep: :crazy:
Doh!! I should have my posting rights taken away before 10am..
MarkLT1 in the morning :sleep: :sleep: :crazy:
