Low BLM

[87 Eddie]

I'm having an issue with my BLM reading pretty low. Couple weeks ago it was reading 90-92. I replaced the stock MAF with a 85mm, reset the ECM and drove the car a few miles. BLM is still reading low at 96. Took a look at the plugs to see if there was a noticeable issue and all of them looked fine. I looked at my fuel pressure and it was at 49. I brought it down to 43 line off and there was no difference with the BLM.
Last owner changed the injectors and chip. From looking around, I'm pretty sure they are a set of 009's injectors with Red Armstrong chip. I've looked around and have the following as potential parts that can contribute. Coils, injectors, O2 sensor, possibly red Armstrong chip.

Anyone with a similar issue that can help? I'm trying to avoid replacing all these parts guessing what's causing the low reading. Here's my other readings.

AF - 5
L8 - 32 to 35
Bat - 13.7
Int - 122 to 132
Ats - 126
TPS - .44 to .46
IAC - 0
CC - Range from 0 up to 254

 

[BuickMike]

Is this only at idle, or does it also read low when you are cruising around? If only at idle, are you in closed loop or open loop at idle? Low BLM is a rich condition, so you are not looking for anything like a vacuum leak, unmetered air, or low fuel pressure issue. What translator are you using? Are you sure you have it set correctly for the MAF you are using?

 

[1KWIKSIX]

Correct me if I'm wrong....but shouldn't fuel pressure be 42-43 line on and maybe around 37 line off? This may explain or would at least contribute to your rich condition.
Get rid of Red Armstrongs' chip & order one made for your set up from Eric at TurboTweak or Bob Bailey's Extender chip.
No IAC reading? Maybe try to remove it and clean out any carbon.....it should be somewhere in the low 20's.
As a last resort, if this doesn't fix it, may have to replace it?
CC counts don't look right....might want to change your O2 sensor to a Denso to rule out any malfunctioning 02 sensor.

 

[pacecarta]

Correct me if I'm wrong....but shouldn't fuel pressure be 42-43 line on and maybe around 37 line off? This may explain or would at least contribute to your rich condition.
Get rid of Red Armstrongs' chip & order one made for your set up from Eric at TurboTweak or Bob Bailey's Extender chip.
No IAC reading? Maybe try to remove it and clean out any carbon.....it should be somewhere in the low 20's.
As a last resort, if this doesn't fix it, may have to replace it?
CC counts don't look right....might want to change your O2 sensor to a Denso to rule out any malfunctioning 02 sensor.

fp is supposed to be set 43 line off , should drop to 37 line on, go from there , if you are using alittle fuel rail mounted gauge to check fuel pressure , those can be wrong , you need to test the fuel pressure with a known good gauge like a test gauge .

"iac at 0" doesn't mean its defective , start by turning the iac screw back (counterclockwise) to close the throttle blade so that the iac can do its job of regulating the air to hold the idle commanded by the chip

cross counts on a closed loop idle chip should run the 0-255 range in 90 seconds or so . on a turbotweak chip it has open loop idle and the fueling isn't regulated by the o2 so it doesnt need to flip across the 450mv o2sensor point so cross counts will be almost at a stand still except for when the chip momentarily goes to closed loop and peeks in (watch the dot on scanmaster)

 

[87 Eddie]

Is this only at idle, or does it also read low when you are cruising around? If only at idle, are you in closed loop or open loop at idle? Low BLM is a rich condition, so you are not looking for anything like a vacuum leak, unmetered air, or low fuel pressure issue. What translator are you using? Are you sure you have it set correctly for the MAF you are using?

Readings posted were all at idle. BL jumps to 120 while driving. I'm using the 6.25 translator set to ON ON ON OFF and 0 at WOT. I had this issue before changing the MAF. I was hoping it would help but nothing changed.

 

[87 Eddie]

fp is supposed to be set 43 line off , should drop to 37 line on, go from there , if you are using alittle fuel rail mounted gauge to check fuel pressure , those can be wrong , you need to test the fuel pressure with a known good gauge like a test gauge .

"iac at 0" doesn't mean its defective , start by turning the iac screw back (counterclockwise) to close the throttle blade so that the iac can do its job of regulating the air to hold the idle commanded by the chip

cross counts on a closed loop idle chip should run the 0-255 range in 90 seconds or so , ona turbotweak chip it has open loop idle and the fueling isnt regulated by th o2 so it doesnt flip across the 450mv point so cross counts will be alost at a stand still

I'll take a look at the IAC. Readings do go up as I drive but stay at 0 while I'm idling.

 

[pacecarta]

iac in park at idle warmed up should be set 15-20 or so , just make sure its not at 0 so it can do its job over with changes in the climate

also tps should be set so it doesnt exceeed .46 otherwise you may step off idle parameters and be in the next blm cell , so set it just a tick lower

 

[fastblackracing]

Pretty sure the armstrong chip is not designed to work with your 85 mm mass air. And the fuel pressure should be 43#vacuum line OFF. ...Putting the vacuum line on should lower the fuel pressure to 36-37#..... Make sure you know what injectors you have to get a proper chip. Does the fuel pressure respond immediatley when you put the vacuum line on and off?...... I have seen some where the metal pipe that provides the pressure signal was plugged up causing the reference signal to be delayed or non existing. As buick mike side low blm indicates a rich condition.....for test purpose only if all else checks ok lower the fuel pressure to 30# line OFF and test drive, no full throttle just test.......see if the numbers come up. I suspect your chip/mass air settings or cal is off.

 

[getdowngranny]

After reading all of the symptoms, I think your issues are chip related. I would order a chip from Eric with your setup burned and then go through the procedures to properly set IAC and TPS just to make sure those two are set correctly.


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[Ttype6]

I'm having an issue with my BLM reading pretty low. Couple weeks ago it was reading 90-92. I replaced the stock MAF with a 85mm, reset the ECM and drove the car a few miles. BLM is still reading low at 96. Took a look at the plugs to see if there was a noticeable issue and all of them looked fine. I looked at my fuel pressure and it was at 49. I brought it down to 43 line off and there was no difference with the BLM.
Last owner changed the injectors and chip. From looking around, I'm pretty sure they are a set of 009's injectors with Red Armstrong chip. I've looked around and have the following as potential parts that can contribute. Coils, injectors, O2 sensor, possibly red Armstrong chip.

Anyone with a similar issue that can help? I'm trying to avoid replacing all these parts guessing what's causing the low reading. Here's my other readings.

AF - 5
L8 - 32 to 35
Bat - 13.7
Int - 122 to 132
Ats - 126
TPS - .44 to .46
IAC - 0
CC - Range from 0 up to 254

Do you like the way the car runs?
Have you removed power from the computer,to reboot it,since you first noticed these numbers?
Was there a time recently when the BLM number was higher?
Your computer is removing as much fuel as it is capable of removing at an idle.
You say that you have an 85mm MAF so your base MAF knob should be set to 6. If it is,you could set it to 8 to lean the idle fuel 10%.
This should get the BLM number up from the current number.
How long does it take for the IAC to bottom out after a cold start in the morning?

 

[87 Eddie]

Pretty sure the armstrong chip is not designed to work with your 85 mm mass air. And the fuel pressure should be 43#vacuum line OFF. ...Putting the vacuum line on should lower the fuel pressure to 36-37#..... Make sure you know what injectors you have to get a proper chip. Does the fuel pressure respond immediatley when you put the vacuum line on and off?...... I have seen some where the metal pipe that provides the pressure signal was plugged up causing the reference signal to be delayed or non existing. As buick mike side low blm indicates a rich condition.....for test purpose only if all else checks ok lower the fuel pressure to 30# line OFF and test drive, no full throttle just test.......see if the numbers come up. I suspect your chip/mass air settings or cal is off.

The injectors are definitely set for the chip in the car. I found the package and directions that were left from the previous owner. Fuel pressure drops instantly when vacuum is removed. This issue was happening long before I changed the MAF to the 85mm. I was running the stock MAF before so figured it was on its way out and swapped it for the 85.

After reading all of the symptoms, I think your issues are chip related. I would order a chip from Eric with your setup burned and then go through the procedures to properly set IAC and TPS just to make sure those two are set correctly.
Sent from my iPhone using Tapatalk

I'm thinking the same. I've read several issues caused by older chips. Time for an upgrade.

Do you like the way the car runs?
Have you removed power from the computer,to reboot it,since you first noticed these numbers?
Was there a time recently when the BLM number was higher?
Your computer is removing as much fuel as it is capable of removing at an idle.
You say that you have an 85mm MAF so your base MAF knob should be set to 6. If it is,you could set it to 8 to lean the idle fuel 10%.
This should get the BLM number up from the current number.
How long does it take for the IAC to bottom out after a cold start in the morning?

I'm OK with the performance for now. I'm trying to get the car running right so I can install an Alky kit. I removed power to the computer and had the same results once the car warmed up. I'm not sure how long the BLM numbers have been this low. I started to notice them a couple months ago. I have the knob at 6, I'll have to try setting it to 8 and see what that does. I reset the IAC and TPS yesterday, IAC set around 20 and TPS to .44. RPM's dropped from 950 to 650-675. The only thing I'm noticing now is once it warmed up, I notice the idle is acting up. Sounds like the car wants to shut off and then spikes back to normal. Car was doing this before but it's more noticeable now since the RPM's are much lower.

 

[BuickMike]

Wait a sec....fuel pressure goes down with vacuum off? Double check that. If that is true, then you have something wrong with your regulator. Vacuum will lower psi from the static setting. Boost will raise it.

 

[87 Eddie]

Wait a sec....fuel pressure goes down with vacuum off? Double check that. If that is true, then you have something wrong with your regulator. Vacuum will lower psi from the static setting. Boost will raise it.

Sorry, meant to say vacuum drops with line on. Drops to 37. Line off is at 43.

BTW adjusting the IAC and TPS raised BLM's to 100.

 

[BuickMike]

Oh, ok. You are good then.

 

[87 Eddie]

Update on what was causing my BLM numbers to read low. I ended up replacing my Armstrong chip for a Turbo Tweak and all my issues went away. BLM is reading 128, my idle is nice and smooth and the smell of raw fuel coming from the exhaust has decreased significantly. I took the car for a drive and was surprised on how different the car drove.