BLM's shooting up to over 150 on decel
12-22-2017, 08:07 PM
#1
Supreme Member
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BLM's shooting up to over 150 on decel
I'm not sure what I did, but on a datalogging run the other day I noticed the BLM's are skyrocketing to 150-160 on decel...
Problem too is it's inconsistent... sometimes it'll be up to 160, other times only up to 140...
So if I chase the 160 with VE table mods, I can end up with BLMs down to 118.
Also, my BLM history can show one cell at 160 with the one right next to it at 128.
Is the BLM learn even supposed to be on during decel? Is there anyway to lock it to 128?
The engine doesn't seem to be doing anything funky by seat-of-the-pants feel, but I'd still like to stabilize the BLMs if possible...
What should I be looking at here?
Problem too is it's inconsistent... sometimes it'll be up to 160, other times only up to 140...
So if I chase the 160 with VE table mods, I can end up with BLMs down to 118.
Also, my BLM history can show one cell at 160 with the one right next to it at 128.
Is the BLM learn even supposed to be on during decel? Is there anyway to lock it to 128?
The engine doesn't seem to be doing anything funky by seat-of-the-pants feel, but I'd still like to stabilize the BLMs if possible...
What should I be looking at here?
12-23-2017, 09:03 AM
#2
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Re: BLM's shooting up to over 150 on decel
Not at all unusual. I don't believe that $8D has an open loop decel feature. I did find this which you may be able to use for disabling BLM updates on decel;
L851A FCB 0 ; IF MAP L.T. 0 then disable BLM update
The INT will still move, but that updates faster then the BLM.
RBob.
L851A FCB 0 ; IF MAP L.T. 0 then disable BLM update
The INT will still move, but that updates faster then the BLM.
RBob.
12-23-2017, 02:01 PM
#3
Supreme Member
Thread Starter
Re: BLM's shooting up to over 150 on decel
Not at all unusual. I don't believe that $8D has an open loop decel feature. I did find this which you may be able to use for disabling BLM updates on decel;
L851A FCB 0 ; IF MAP L.T. 0 then disable BLM update
The INT will still move, but that updates faster then the BLM.
RBob.
L851A FCB 0 ; IF MAP L.T. 0 then disable BLM update
The INT will still move, but that updates faster then the BLM.
RBob.
12-23-2017, 04:12 PM
#4
Supreme Member
Thread Starter
Re: BLM's shooting up to over 150 on decel
Oh I see it (I think).... It's in Tunerpro. But it says the address in hex is 0x5AB?
DE, MAP Enable => Enable DE if MAP is Less Than or Equal to THIS Value. Stock Bin is set to "0"
So if it's set to zero at the factory, how is it coming on? MAP is never less than 0.
DE, MAP Enable => Enable DE if MAP is Less Than or Equal to THIS Value. Stock Bin is set to "0"
So if it's set to zero at the factory, how is it coming on? MAP is never less than 0.
12-23-2017, 04:47 PM
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Re: BLM's shooting up to over 150 on decel
Yes, say you set that parameter to 36 KPa. Full off throttle at RPM will easily pull lower then that number. At 36 and higher MAP and the BLM updates take place.
Drop to 35 KPa or lower and the BLM updates are disabled.
DE is decel enleanment, it is used on throttle lifts to reduce the volume of fuel. Basically, the opposite of AE.
RBob.
Drop to 35 KPa or lower and the BLM updates are disabled.
DE is decel enleanment, it is used on throttle lifts to reduce the volume of fuel. Basically, the opposite of AE.
RBob.
12-23-2017, 04:56 PM
#6
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Re: BLM's shooting up to over 150 on decel
Ah... so the minimum map in the VE table is 20 kPa. So if I set it to 20 kPa, then it should disable BLM updates at any MAP value that's off the table..?
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12-24-2017, 04:21 PM
#8
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12-25-2017, 02:07 PM
#9
Senior Member
Re: BLM's shooting up to over 150 on decel
Just a thought, but High BLMs on decel can also be caused by an exhaust leak, generally close to the o2 sensor.
A short time after changing collector gaskets, began to experience random high BLMs on decel. Fixed it with a highly sophisticated procedure. Cut a small hole in empty plastic water bottle and stuck it up tail pipe. Air hose into small hole and held always-on with clamp. Squirted soapy solution all around exhaust connections and found the leak immediately. Repaired and BLM issues gone.
HTH
A short time after changing collector gaskets, began to experience random high BLMs on decel. Fixed it with a highly sophisticated procedure. Cut a small hole in empty plastic water bottle and stuck it up tail pipe. Air hose into small hole and held always-on with clamp. Squirted soapy solution all around exhaust connections and found the leak immediately. Repaired and BLM issues gone.
HTH
12-28-2017, 11:57 AM
#10
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Thread Starter
Re: BLM's shooting up to over 150 on decel
Making this change had exactly the desired effect! Awesome!
Once again, RBob proving he is 'da MAN!
Elky, yeah, I'm pretty sure I have no exhaust leaks. My headers are ball and socket and whenever I pull them off, I never see any soot trails on the collectors (and I don't hear any sounds indicative of a leak).
Once again, RBob proving he is 'da MAN!
Elky, yeah, I'm pretty sure I have no exhaust leaks. My headers are ball and socket and whenever I pull them off, I never see any soot trails on the collectors (and I don't hear any sounds indicative of a leak).
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