Duramax Diesels Forum Truck of the Week
  #1  
Old 09-08-2018, 02:08 PM
Ineedhelp Ineedhelp is offline
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Default 2003 lb7 keeps giving maf code.

Recently blocked the egr and removed the vacuum pump and intake heater. Been getting maf code since. New sensor. Same deal. Only throws the code when I start it. Pulling 53-56 g/s flow at idle. This is driving me nuts having to reset the light every time I start my pickup.
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Old 09-08-2018, 02:48 PM
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Did you retune it after the new mods?? That’s your maf issue.... you prob have some other associated codes.
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Old 09-08-2018, 03:09 PM
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At start up the ecm goes through the egr checks. It is looking for a drop in air flow since some of it will be provided by the egr. If it is blocked then it won't see the drop and may trigger the code. Would likely get egr codes too

Need to have the tune adjusted for the changes
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Old 09-08-2018, 03:48 PM
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Had it tuned after and spoke to the tuner he suggested wiring problem but I canít find anything wrong there. I have a device that reads the flow and canít see that as the problem.
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Old 09-08-2018, 04:06 PM
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53-56 g/s does seem a little high. Shouldn't it be closer to 40ish.

Stock intake?
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2008 Chevrolet 3500HD DRW LTZ
285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

2006 BRM Jetta TDI. Injectors, turbo, Malone custom tuning on ecm and tcm
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  #6  
Old 09-08-2018, 09:10 PM
Ineedhelp Ineedhelp is offline
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4Ē k&n intake. Cleanable cloth model.
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Old 09-08-2018, 09:26 PM
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Well, there's your first mistake. K&N intakes are terrible for these trucks.
Have you put the stock intake back on to see if the code comes up again?
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Old 09-09-2018, 11:05 AM
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Donít have the stock intake. K&N was on it when I bought it.
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Old 09-21-2018, 08:35 PM
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53-56 is way to high and will code. Should be down in the mid 30's to low 40's for an lb7. I would be looking for boost leaks myself.
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