NOOB trying to tune Open Loop MAF- E38 2007 4.8 Silverado in a swap

[Grip]

I am brand new to tuning and am trying to do some Open Loop, MAF tuning on my 5.3 swaped RX7. The ECM and original tune are from a 4.8L Silverado. I have a wide band and with some advice from a friend tried to log AFR ERR but realized the scanner is showing 0HZ on my MAF. I checked power, ground, and continuity to the EMC on the yellow wire. All check out good. Still no MAF HZ reading in the scanner. I added the PID for MAF status and it shows as "MAF Failed". I don't know why. Can someone take a look at my tune and see if something is set up wrong?

Thanks in advance!

Eric

[Grip]

Anyone?

[schpenxel]

Something is either wrong with the wiring or wrong with the MAF IMO. MAF frequency will show up whether it's in MAF only or SD, doesn't matter.. if it's working, MAF frequency will show up. MAF airflow is also staying the same value the entire log.

Check for codes and see what is showing

[Grip]

Something is either wrong with the wiring or wrong with the MAF IMO. MAF frequency will show up whether it's in MAF only or SD, doesn't matter.. if it's working, MAF frequency will show up. MAF airflow is also staying the same value the entire log.

Check for codes and see what is showing

Thanks for your input. So, over the weekend, I checked the wiring, again. 12v ignition on on the pink wire. Ground on the black wire. Continuity on the yellow wire. The yellow wire arrears to be fully seated in the X connector at the ECM.

I picked up another MAF and scanned it again. Same result. No hz reading in the scanner. I pulled my computer into another car and the maf reading shows so I don't think it is an issue with HP Tuners or my my AFR err chart.

I checked for codes and there are none.

I guess I need to so a compare with a stock tune to see if there are settings that are causing the MAF to fail.

[schpenxel]

Weird. Maybe I'm wrong.. I've just never seen one not show a MAF frequency even with the MAF failed, if there was one present. Maybe yours is different?

Yeah check out the MAF fail settings and see how they look vs. stock. It's worth a shot.

[Grip]

Just a thought. The Maf I am using is a card style one (GM Performance part, similar to a 2010-11 Camaro and others). The original truck one is different but the plugins the same.

Is it possible that there is some incompatibility?

[schpenxel]

You might be on to something. I have a 2007 escalade, I'll check out the MAF wiring on it when I get home. The first wiring diagram I found showed the wiring being different between trucks and the newer card style MAF's. Not sure if they were right, though...

Does the IAT reading show up correctly? Are you using the sensor built into the MAF or a separate one?

[Grip]

The IAT is working and is built in. The wires for the IAT are tan and tan/wht if I remember correctly.

Thanks in advance!

[Grip]

Tonight, I checked the wiring again and even made sure I had 12+ volts with the engine running. Everything checks out. I then probed between the 12v pink wire and the black wire to double check ground. I get the same reading as when I check between the bat post on the alt and the ground wire.

Is it possible that my ECM has somehow lost that piece of data? I have another E38 ECM that isn't registered with HP Tuners. Should I use credits to register it and unlock VATS. Then I could copy any differences in the tune from old to new.

I'm really confused here.

[SultanHassanMasTuning]

is the car running, while running can you unplug the maf and see what happens

its normal that the maf see Htz while in SD more/failed

[Grip]

Thanks for your input. I'm not trying to be in SD mode. I'm trying to be in Open Loop MAF. I have the MAF plugged in and am not seeing any HZ and it shows up as failed.

I have tried a second MAF sensor. Same result

Checked the MAF wiring.

Scanned another vehicle to make sure the issue isn't with HP Tuners.

Running out of ideas.

[adunphy]

Thanks for your input. I'm not trying to be in SD mode. I'm trying to be in Open Loop MAF. I have the MAF plugged in and am not seeing any HZ and it shows up as failed.

I have tried a second MAF sensor. Same result

Checked the MAF wiring.

Scanned another vehicle to make sure the issue isn't with HP Tuners.

Running out of ideas.

Did you swap the + and -? The stock MAF and the Card MAF flip polarity. Swap your pink wire with your black wire (or whatever the colors are in B and C on the connector.

[NJ_Phil]

The card MAF also needs 5v since there's no on board regulator. With the key on and the sensor unplugged, you should see +12v only on the ORANGE wire.

Pin A is an open collector MAF frequency output. There's a pullup resistor on the ECM going to 5v so it should be around 5v
Pin B is GROUND
Pin C is Ignition voltage +12.
Pin D is +5v supplied from the ECM, the reference voltage for IAT and MAF signals
Pin E is IAT sensor analog out

maf.png

[Grip]

Oh wow! You are the first person to mention this. I had NO idea. I will try it tomorrow and report back. I REALLY hope you are right.

[NJ_Phil]

You might have fried both MAFs if you had 12v going to the reference voltage.

[Grip]

You might have fried both MAFs if you had 12v going to the reference voltage.

NJ Phil, you are the man!!!!

The MAF now works. Now I can MAF tune it. right now, its a mess. The ECU is from a 4.8 Silverado. The engine is a 5.3 that has been cammed. AFR's at idle are 17:1.


Any help would be greatly appreciated.

[schpenxel]

And fuel trims are maxing out, 50%+

That thing needs some major rough adjustments to the MAF table

[Grip]

Schpenxel,

Thanks! And I see that. Question:
With it being that lean at idle, would you suspect a vacuum leak? Since the DOD has been deleted and a cam swap, the PCV hoses are ran in an "unconventional " route. I have a hose going from the hose barb at the right front of an LS3 valley pan to the original truck intake, just behind the throttle body. I'm told that the intake has a metered hole instead of a real PCV valve.

[scottt28]

And fuel trims are maxing out, 50%+

That thing needs some major rough adjustments to the MAF table

Peanut gallery here... at 2:31:xxx, the short term fuel trims go from 28.91 to zeeeeero. My chart goes from -20 to +20, so I'd like to understand why it goes all the way to ~29 before going poof. Why does it disappear? I also noticed that the graphs have values in some cells and 0.0000 in other cells. Is that what you mean by "maxing out"?

Also... I have the same basic PCV system as Grip. I think it's a 5/16 or 3/8 fuel hose going from the nipple on the valley plate to a fitting I added to the manifold (drilled and tapped a hole for a 1/4 NPT fitting) behind the throttle body. Fresh air passes through a breather on the passenger side rocker cover. Other than potentially sucking oil vapors into the intake, is there any problem with this setup?

[schpenxel]

It's probably throwing an error right there from them being so high previously