I am so confused right now... I need to start over..... please help :)

Over the x-mas break, I rebuilt the spare 700r4. Got that put in and noticed a much better running drive train it seems. All the tuning I've done up to that point seemed to be no good anymore.

The setup is as follows, a 3.4l engine with a 4.3 throttle body, edelbrock long tube headers and a 1228062 ECM. (I'm using that ECM because it being more simple for me. I might later swap to the 7747 when I get a better understanding of everything going on.)

So, I had to take care of a sticky throttle valve issue when I go WOT by using a transgo tv kit. I've got the tranny back together and took it for a test drive and recorded some logs. Right off the bat, I see my knocks have skyrocketed and have no idea why other than I believe that the TCC lockup has a lot to do with it.

The TCC was originally controlled by a vacuum switch, but is now controlled by the ECM.

But lets back up a little to the tuning of the spark and ve tables first.

We are running E10 here and who knows what the ethanol mixture actually is. I've got the Stoich AFR set in the BIN for 14.1 as once suggested by Mark. I need to change the AFR gauge to Lambda value display.

But where I am confused is the Stoich setting in the BIN. For example, if the logs show that you are running lean because the stoich value is 14.7 for e10, then would setting the value to 14.1 essentially be the same as a global adjustment on the VE table to richen the readings?

This is confusing the poo out of me and I don't know why unless I am thinking too much about it.

Based on AEM's manual on the wide band sensor, it discusses that the factory o2 will typically show a rich indication for a Lambda value of less than one.

In this case, with straight gasoline and the stoich set at 14.7, I should see 128 for a perfect burn, but with E10, I think I would be seeing BLM values lower than 128 meaning the ECM is adding fuel to compensate for fuel that requires a higher mixture.

What BLM values would I see if I set the Stoich value in the BIN to 14.1?

Will the narrow band o2 sensor then report rich?

Number greater than 128, means the ECM is adding fuel.

AFAIK, setting the stoich setting to 14.1 should then set the ECM to make calculations based on that being the switch point (lambda 1.0) when read from the NBO2 sensor. If there are other tables that also reference AFRs you may have to richen them by the same amount to have everything line up again.

Keep in mind that the stock ECM does not really reference AFRs, at least not accurately, since the NBO2 sensor is really a switch at lambda 1.0.

That being said I haven't noticed much of a difference playing with the stoich settings.

Oh ok, I've always understood it to mean that a number, either INT or BLM, being higher than 128, that the mixture was running lean, and that below 128 was rich.

I don't know if that makes sense or not.

Quote:

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Originally Posted by damanx

Oh ok, I've always understood it to mean that a number, either INT or BLM, being higher than 128, that the mixture was running lean, and that below 128 was rich.

I don't know if that makes sense or not.

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Yes, that is correct, but you stated it the other way around in your first post.

>128 means the ECM is adding fuel <128 it is trimming fuel.

Now as I understand it with my AEM wide band gauge in AFR display mode, I would be at stoich with a display of 14.1 using e10, or in Lambda display reading of 1.0.

That has been throwing me off also.

So, as I understand it now, the narrow band OE o2 sensor detects percentage of oxygen, because, regardless of the fuel, the fuel's AFR would leave the same amount of oxygen once burned as detected by the sensor.

Then, setting the Stoich value to 14.1 in the bin simply just causes a global increase in fuel being added, which then, if in a perfect world, 128 readings would simply mean the mixture is all good.