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LS Experts - P0102 Code

TMac

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Joined
Sep 12, 2018
Messages
117
Location
GA
Hoping someone on here might have some ideas I haven’t checked yet. I keep triggering a P0102 code (MAF) every time I start the engine. Appears to be running fine, maybe a little lean just off the exhaust smell. I clear the code and it immediately comes back when I start it. New MAF sensor, 5v and 12v at the plug (5 wire plug), ground is good. Checked the intake and it appears no leaks. Looks to be reading fine at the ecu (every once in a while I’ll see a blip in the IAT if I use a 60 second graph).
Checked all my vacuum lines and they seem to hold vacuum. Any other ideas?

Gen 4 6.0
BTR stage 2 cam
Tuned by Injected
Factory harness cut down
 

TMac

Well-Known Member
Joined
Sep 12, 2018
Messages
117
Location
GA
What's the values the ECM sees ?

P0102 is low reading IIRC
Here is what I’m showing for MAF. IAT is measuring correctly
 

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RustyC

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Joined
Dec 15, 2010
Messages
1,224
Is this a new build or has the engine been running code free prior to this?
 

TMac

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Joined
Sep 12, 2018
Messages
117
Location
GA
Is this a new build or has the engine been running code free prior to this?
Newish. Had the code, changed out the maf and the intake and it was gone for a few weeks, then had it retuned and now it’s back. Don’t know if it could be related to the tune or not cause I’m dumb and didn’t check prior to getting it retuned...
 

Lil ugly

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Joined
Oct 6, 2011
Messages
685
Location
Jacksonville, Fl
It is possible that the tuner did not turn everthing back on in the DTC 's . Typically when you work on tuning a vehicle with a cam you will fail the MAF so you dont get data that is constantly being adjusted. Then when done tuning you turn the MAF back on. You will get a light and code while it is failed. It may not be the issue but it is an easy thing to check.
 

TMac

Well-Known Member
Joined
Sep 12, 2018
Messages
117
Location
GA
It is possible that the tuner did not turn everthing back on in the DTC 's . Typically when you work on tuning a vehicle with a cam you will fail the MAF so you dont get data that is constantly being adjusted. Then when done tuning you turn the MAF back on. You will get a light and code while it is failed. It may not be the issue but it is an easy thing to check.
I've been digging through some threads on the HP Tuners forum and I'm starting to suspect it's related to the tune. I'm wondering if the airflow delta table needs to be adjusted due to the cam or if something else was modified in regards to the MAF setting

Its odd that it trips it as soon as I key it on, but is showing MAF and IAT on the ECU. From what I can find typically if the issue is with the MAF it takes driving it to trigger the code
 

lt99ls1

Well-Known Member
Joined
Aug 16, 2011
Messages
213
Location
Dalton Ga
Is your wiring harness a factory one that has been cut down or aftermarket? Have you checked continuity with a multimeter on the wires going from the maf to the ecm?
 

Bebop

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Joined
Jan 27, 2013
Messages
1,812
I've been digging through some threads on the HP Tuners forum and I'm starting to suspect it's related to the tune. I'm wondering if the airflow delta table needs to be adjusted due to the cam or if something else was modified in regards to the MAF setting

I read the same topics.
Not sure this would be the solution vs masking it, but is an idea.
 

TMac

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Joined
Sep 12, 2018
Messages
117
Location
GA
Larry - it was a cut down harness. From my scan tools it looks like the ECM is getting the correct data (for example: IAT is dead on with AAT when I fire it up when cold). Also MAF (g) appear to be in range when I convert to hz

@Bebop - agree, but at this point I'm not sure what else it could be? I ordered a new MAF that I'm going to put on today to see if for some reason that fixes it
 

TMac

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Joined
Sep 12, 2018
Messages
117
Location
GA
Spoke to the tuner and it turns out he changed my tune to use speed density... Anyone know a good tuner within a couple of a hours of Atlanta that tunes using MAF?
 

Lil ugly

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Oct 6, 2011
Messages
685
Location
Jacksonville, Fl
Your vehicle will always fail to a speed density tune if the MAF has any issue or if you are outside of the MAF parameters for any reason. Not having MAF is not a major issue unless you are going to be driving in a large variety of terrains that will cause your SD tune to be out of whack for some reason. Jeeps like TJ come from the factory with out MAF because once it gets dirty it fails and you run on SD anyways. That being said your tuner should be able to set you up so you dont have a light if he is going to have your tuned on SD. I dont run MAF on my rig, I have my IAT sensor set into my air cleaner and run SD. Typically you wont have any issue running like this. If you are drag racing you may need to have several SD tunes to adjust for temps, altitude etc but for a general purpose rig most of us wont notice the slight difference in woopows due to the atmospheric changes.

I am no help with a tuner in Atlanta, sorry.
 

TMac

Well-Known Member
Joined
Sep 12, 2018
Messages
117
Location
GA
Your vehicle will always fail to a speed density tune if the MAF has any issue or if you are outside of the MAF parameters for any reason. Not having MAF is not a major issue unless you are going to be driving in a large variety of terrains that will cause your SD tune to be out of whack for some reason. Jeeps like TJ come from the factory with out MAF because once it gets dirty it fails and you run on SD anyways. That being said your tuner should be able to set you up so you dont have a light if he is going to have your tuned on SD. I dont run MAF on my rig, I have my IAT sensor set into my air cleaner and run SD. Typically you wont have any issue running like this. If you are drag racing you may need to have several SD tunes to adjust for temps, altitude etc but for a general purpose rig most of us wont notice the slight difference in woopows due to the atmospheric changes.

I am no help with a tuner in Atlanta, sorry.
Should have included - from what I understand, SD will always trigger the P0102 code which will prevent me from passing emissions. I don’t drive one the street a lot, just short errands around the house, but it’s fun to drive. That’s why I need a MAF tune
 

Bebop

Well-Known Member
Joined
Jan 27, 2013
Messages
1,812
Dude.
Everything makes sense then.

Just get your tuner to turn the DTC check off.
 

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