TDStuart Tuning Adventure

[tdstuart]

Submitted a post on the pcm tec forums. https://forum.pcmtec.com/topic/2337-2015-mustang-gt-low-load-map-and-torque-at-wot-no-idea-why/

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[tdstuart]

IF MAF and LOAD aren't agreeing:

1. MAF sensor malfunction: The MAF sensor may not be accurately measuring the amount of air entering the engine, causing a discrepancy between the MAF and Load readings. This can also be it's positioning in the tube.

2. Intake leaks: A vacuum leak or unmetered air entering the intake system after the MAF sensor can lead to discrepancies between the MAF and Load readings. At higher throttle positions, these leaks can become more apparent as more air is drawn into the engine.

3. Airflow restrictions: A clogged air filter or other restrictions in the intake system can disrupt the airflow, causing discrepancies between the MAF and Load readings.

4. Tuning issues: In some cases, discrepancies between MAF and Load readings can be caused by errors or inaccuracies in the engine tune itself.

First 3 aren't the issue. Once I apply the baro minimum patch my fuel trims are perfect and load is exactly what the manual calculations show. Its also the stock cai so i don't think maf placement is a problem and its a brand new maf.

MAF isn't changing between the baro minimum fix vs no fix. Load, MAP, Torque, and Effective throttle area change.

 

[WildHorse]

Well I may have missed reading a few pages of this thread ha-ha. Glad it's sorted.

 

[K4fxd]

I don't think you wasted your money on the MAF sensor. It was reporting bogus IAT's.

Putting the stock CAI and injectors proved this is not a tune issue with those parts. I don't like throwing parts at things but if you do have a known good TB it won't hurt to try it.

 

[tdstuart]

Well I may have missed reading a few pages of this thread ha-ha. Glad it's sorted.

Its only 34 pages so far haha

Ya the 2 theories right now is its some magic pcm wizard dust (I'm actually betting its this) or maybe some physical issue that isn't super clear. TB is the best guess at a physical issue but the logs look fine and the pcm is saying that the tb is fine so idk.

 

[tdstuart]

I don't think you wasted your money on the MAF sensor. It was reporting bogus IAT's.

Putting the stock CAI and injectors proved this is not a tune issue with those parts. I don't like throwing parts at things but if you do have a known good TB it won't hurt to try it.

We will have to see what the iats look like when the pmas goes back on and if it still climbs when you go wot. Besides the one time it was clearly acting up I think in general it was reporting correctly.

 

[GregO]

My point is that how much more do you want me to replace? First it was the maf, then the cai, then the injectors.

I didn’t say anything about injectors or MAF sensor replacement. I did suggest returning to the stock box which was used not new and cost you nothing.
I still have serious reservations about the PMAS fender well Filter/MAF housing, sensor location.

 

[GregO]

I don't think you wasted your money on the MAF sensor. It was reporting bogus IAT's.

We don’t know this because more than one thing was changed again.
New sensor was used in OEM air box not the former PMAS/JLT sensor.
At this point at least the closed box is in and the Fender Well gizmo is out.

Now about the TB hanging up over the winter and then magically fixing itself……..

 

[engineermike]

I think it’s the SD model and I have a pretty good explanation as to why.

 

[GregO]

I think it’s the SD model and I have a pretty good explanation as to why.

I’m listening.

 

[tdstuart]

@markmurfie what is the baro minimum controlling? Obviously not the actual minimum pressure the car is using. Is it a learned parameter?

Maybe the car is learning something from part throttle? Maybe the cams are affecting what the car thinks is happening?

 

[tdstuart]

I think it’s the SD model and I have a pretty good explanation as to why.

Please bless us with the answer

 

[WildHorse]

I still have serious reservations about the PMAS fender well Filter/MAF housing, sensor location.

Me too. I think the MAF placement is less than ideal. Way to far from the TB.
At this point, I'd seriously consider putting the MAF closer to the TB if you wanna
keep the fender mount.

But I'm no engineer, and I'm sure James knows what he's doing.

 

[K4fxd]

I think it’s the SD model and I have a pretty good explanation as to why.

I'd be interested in this also.

 

[GregO]

Me too. I think the MAF placement is less than ideal. Way to far from the TB.
At this point, I'd seriously consider putting the MAF closer to the TB if you wanna
keep the fender mount.

But I'm no engineer, and I'm sure James knows what he's doing.

I think they did the best with the parts they inventory to keep the price point competitive.
I have my own opinions on MAF sensor placement.
How many OEM MAF sensors have you seen placed in a vertical duct riser vs. horizontally ducted ?

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