Quick MAF question.

[obzidian]

I'm having an issue where my commanded AFR doesn't match what I'm actually commanded.

For example, in forced Open Loop with a Stoich of 14.699 and a PE EQ ratio of 1.312 my commanded PE AFR should be around 11.2 AFR. However, on the scanner I'm getting about a point lower. (10.2)

I'll load my logs/scans in a second but those anyone know why this is happening and how to fix it?

Thaks y'all.

[mrvedit]

There are other tables which can affect the commanded AFR.
Look under Engine -> Fuel Control -> General.
The table "Initial adder vs ECT" enriches according to engine temperature. The table "Initial adder vs IAT" enriches according to inlet air temperature. Check these tables - the "initial adder vs ECT" is typically 0 in normal engine temp ranges.
(I'm just a novice taking a stab at it.)

[obzidian]

No worries, maybe two novices makes one amateur?

I'll look into it. The IAT might make sense the car I was working was a STS-V and she is CONSTANTLY hot. The IAT's (the average of IAT and IAT2) where really high. The car has a very wimpy heat exchanger/reservoir setup. You have to see it to believe it.

[DSteck]

First rule of fight club... post the tune.

[obzidian]

And the second? I will as soon as get back home.

[PGA2B]

Here you go. Not my car, just trying to help.

[DSteck]

And the second? I will as soon as get back home.

Second rule of fight club is post the damn tune.

Looking at it now.



Edit: Why the hell is it commanding 11.2 at idle?

Fuel -> Open & Closed Loop -> Misfire

Set that whole table to 1. More importantly, you need to figure out why it's defaulting to that table.

[obzidian]

Here you go. Not my car, just trying to help.

Thanks buddy!

D: exactly, I'm not sure either. Before I switched over to forced ol, she was readying fine at 14.699.

[PGA2B]

Here is the stock tune.

[DSteck]

Jesus, barely anything is changed. FYI, you can't really calibrate the MAF if you leave VE coefficients enabled.

Are you forcing open loop with the scanner?

[PGA2B]

I was told the STS-V does not use VE so leave it alone??

[obzidian]

Hey PGA, I think I got it.... it was exactly what I thought.

[DSteck]

Share with the class.

[Ben Charles]

While searching I came across this.

No matter what I set my OLFA table too the actual AFR is around 11-12 (when commanding 13.47-14.68 when warming up. I know not to tune the VE table ( 2 bar SD) until I get to operating temps (170-185), but just wondering why AFR is not what I am commanding it. I have tried a lot of things too.

I noticed when i set the OLFA table to around 14.8-15.1 it would start and then die shortly after ( Actual still 11-12 AFR)

Here is my tune if this helps