Log Review

[tayto]

some of that also has to do with the use of ethanol. back when these vehicles were tunes by the factory it was "pure" gas. not uncommon to see the fuel trims off. however this is the beauty of a closed loop system, the ecu can and does correct for this.

[Mwtvvo]

I understand that every engine comes from the factor different and even over the years parts can be changed out of even worn. In my original post, I said that I pulled the motor apart and changed every gasket, oil pump, timing chain, even lapped the valves. I do not know anything about the cam. The compression test I did a week ago showed 140-145 which is low, but I think that was a gauge issue, but the values were very close to each other.

I guess I'm missing something here. I want to tune this soon, but right now I'm just trying to adjust things for optimal performance. The Blms are adjusting the fuel to reach stoich.

Re: INT & BLM clarification
No. An INT or BLM value of 128 is neutral. Not adding or subtracting fuel.

If either is higher then 128, the ECM is adding fuel. IOW, the ECM found that the exhaust AFR was on the lean side and is bringing it back to stoich (or there abouts').

A value lower then 128 (INT or BLM) is removing fuel. the ECM found that the exhaust AFR was richer then stoich, and is trimming it back to the proper value.

RBob.

So even with my blm low 107 the computer is still reaching stoich in CL, but not in OL. This is assuming my injectors and O2 sensor are working correctly. I don't understand why that would be optimal, besides better atomizing, (there must be a way to gauge this too?)

Being that every engine is different from the factory, should be a reason to use the computer to adjust the fuel to optimal performance. That's the beauty of a computer system. I guess I'm asking how do you use the computer to tell if it's optimal.

Im here to tell ya that you cannot trust "BLM" to be spot on accurate..

I just put in my new AEM 30-0300 and at idle i am at 14.x but BLM has me at 140's!!

How do you know 14.x is optimal.

Also, can someone answer my injector duty cycle question?

[PlayingWithTBI]

Also, can someone answer my injector duty cycle question?

With the '7747 ECM you need to apply the patch for BPW and Spark Advance.
TunerPro Hack Patch.JPG

[Mwtvvo]

With the '7747 ECM you need to apply the patch for BPW and Spark Advance.

Okay just making sure, thanks.

Your EBL Flash sent me down a rabbit hole of info. I'm thinking about swapping to the 7427 ecm now. The thread is cluttered with information though. The ebl Flash comes with support lol.

[badgta]

To my understanding, 128 BLM is whatever you set "STIOCH" to in scalars...

So if you set it to 15.3:1 in the computer 128 is 15.3:1.. Could be wrong but pretty sure i am right.

I am just saying that a good wideband is the (ONLY WAY) to go.. Sure idle ya want somewhat leaner, especially if you don't have converters.. No reason to own a vehicle that burns ya eyes out idling. That is crazy. But driving around you want those tables close to 128 so the computer isn't struggling to keep it near whatever you set stioch at..... Then for power, you can work the P.E mode to give ya what ya want..

Yeah i get the whole "14:!" may not be great, one guy claims he gets best mileage and power at 13.x:1.. Saw it at thirdgen.org. All i am saying is don't trust just BLM for tuning...

I'm actually thinking of doing a single 4" converter when i upgrade and supercharge everything. I mean yeah i will lose some power, but how much ya need past 530whpo?!? I mean honestly!?!?

[dave w]

16197427 Data Log Information

BLM - Near Idle.jpg

BLM - Off Idle.jpg

Injector Duty Cycle.jpg

Near Idle.jpg

Off Idle.jpg

Spark Advance.JPG

[dave w]

EBL P4 AFR Averages

Lower AFR.jpg

Upper AFR.jpg

[Mwtvvo]

Thanks for posting that log Dave. I assume you're showing the Blms vs WBO2 and how they show rich while the wide band does not. That's interesting to see. Has anything been done to the engine or the .bin from the log you posted?

My engine is completely stock, so my thinking was to use the Blms to tune the fuel pressure to an ideal setting. I was hoping that a factory tune and factory engine the Blms could be used to adjust the fuel pressure. I also understand a more precise method is a wideband.

[dave w]

The 16197427 data logs (after tuning) were from a "kitchen sink full of go faster parts" modified 5.7 liter. Go faster parts require AFR tuning for optimal performance.

[badgta]

I knew BLM vs actual AFR was wrong.. Don't know why.. Yours is the (SAME) as mine.. Damn thing screams 140's+ at idle but is 14.7:1 perfect...


Crazy stuff huh?