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Pete
Pete, GMC Mechanic
Category: GMC
Satisfied Customers: 24656
Experience:  GM training and dealer tech for 14+ years. Diagnostics
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Pete. we are a mechanic shop. we have replced intake with a

Customer Question

hi pete. we are a mechanic shop. we have replced intake with a afe system. the reduce power code was saying mass air flow sensor. weve replaced that 3 times and if still only reduces power in the rain when tiad has puddles and spkash up
Submitted: 1 year ago.
Category: GMC
Expert:  Pete replied 1 year ago.

Hi my name is ***** ***** I will be happy to help with this today.I need a little more info to assist better.

Can you tell me the year and model of this vehicle as well as engine size?

Can you tell me the fault codes set with this issue?

Let me know so we can continue,thanks Pete.

Customer: replied 1 year ago.
2008 chev drama 6.6 dieselI can't remember the code but it was the mass air flow
Expert:  Pete replied 1 year ago.

Have you checked for any vacuum leaks on the engine with excess air entering the engine?If there is a vacuum leak or turbo component leak this can cause a mass air flow sensor code to set.If the intake is an after market intake and isn't fully compatible with this model this can cause a difference in the way the air enters the cylinders and may set off a mass air flow sensor code as well.In this case with an after market intake that may be designed differently in some cases after market engine programming is needed by an accessory install facility to keep the code from setting.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

Customer: replied 1 year ago.
We haven't check with smoke machine because we don't have one. But we did check all vaccum lines but will check again. We could get a different age intake under warranty. But last week we noticed the pre screen getting wet.. that makes us believe that's the mass air flow may be getting wet. But we tool a pressure washer to the tranny spray by the wheel the front and still can't get a code. I'll tell my tech ti look fir vaccum leak today. I will need more questioned answered. Thanks
Expert:  Pete replied 1 year ago.

Your welcome.Let me know what you come up with here when your ready.

Thanks Pete

Customer: replied 1 year ago.
I scanned truck no codes. We check vaccum leaks and wires nothing.
Customer: replied 1 year ago.
Can I do something with our scan tool
Expert:  Pete replied 1 year ago.

Is the mass air flow sensor still getting wet at all and was a new one installed that isn't getting wet?If you can get me the fault code number this will help.

Customer: replied 1 year ago.
He does have delete kit with Billy dog it mat not throw a code anymore. We just put this on for him
Expert:  Pete replied 1 year ago.

O.k.,it may not set this code with this set up here.Is it still going into reduced power mode even with the delete kit and Billy dog?

Customer: replied 1 year ago.
Last code was p101
Expert:  Pete replied 1 year ago.

Is it still going into reduced power mode now?

Customer: replied 1 year ago.
he was on performance mode. No engine light on just went to reduce engine power and worked after shut off and quit raining
Expert:  Pete replied 1 year ago.

But no new codes have set or no codes at all when this occurred last?

Customer: replied 1 year ago.
No codes at all
Expert:  Pete replied 1 year ago.

This is a tough one for me to answer myself here.I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Customer: replied 1 year ago.
Ok we will check the vaccum lines again could it be the moisture is splashing into air cleaner getting through filter
Expert:  Pete replied 1 year ago.

If your engine air filter is getting wet with this issue here it is possible the air cleaner box is picking up water from outside air or puddles causing this here and would need corrected to resolve this.If it is getting wet you will want to locate the source of the water entering and correct it.

Thanks Pete

Customer: replied 1 year ago.
Cam moisture get through am air filter? I think it's something else. What else cause engine reduce with no check engine light or code.
Customer: replied 1 year ago.
Ya the screen had water stains again so we duct tape all holes inside fender
Expert:  Pete replied 1 year ago.

I apologize for the delay as I was off line the last few days.

Moisture can make it through the filter itself and can cause an issue like this here.I would make sure no water is getting in still and clean any areas that had moisture damage to see if this resolves the issue.If this was already attempted and did not work to correct this here let me know.

Thanks Pete

Customer: replied 1 year ago.
Hello.
I duct tape all holes in fender wells. We need a rain to see if this was the problem. There were more watee stains on the pre screen. If this doesn't work. What els should we do. It's funny that we've put on 100 s of these intakes and never has any problems. Thanks foe now. Will let you know.
Expert:  Pete replied 1 year ago.

Let me know if this resolves this here.This may have been water entering around the holes causing this.

Thanks Pete

Customer: replied 1 year ago.
Just dI'd it again and it's raining out
Expert:  Pete replied 1 year ago.

Is there water in the filter again?

Customer: replied 1 year ago.
Well check in an hour
Expert:  Pete replied 1 year ago.

O.k.,let me know when you find out.

Customer: replied 1 year ago.
There is a wet spot and it's coming from behind headlight can we block that off too. We're worried that it would starve for air
Expert:  Pete replied 1 year ago.

Was the updated air filter housing/grill ever installed?I thought I went over this with you but reading through this I don't see that I did and I apologize as I must have been working with two customers with similar issues here.

Customer: replied 1 year ago.
we installed a afe cold air intake due to regular filter was getting jammed with snow
Expert:  Pete replied 1 year ago.

There is a bulletin out on covering the grill with a cover from GM.Was this ever installed at all?

Customer: replied 1 year ago.
No where
Expert:  Pete replied 1 year ago.

O.k.,let me post the info on this.I am wondering if you have this installed or install it if this will solve the water entering,my guess is the water entering is causing this for sure here and the water entering issue needs resolved.

TECHNICAL Bulletin No.: 08-06-04-054A Date: January 07, 2010 Subject: Snow or Ice Ingestion into Air Cleaner Element, malfunction indicator lamp (MIL) Illuminated, Engine Power is Reduced Message Displayed, DTC P0101 Set (Perform Repair as Outlined) Models: 2007-2010 Chevrolet Silverado 2500/3500 Series 2007-2010 GMC Sierra 2500/3500 Series Equipped with Duramax(TM) Diesel Engine (RPO LMM) Please Refer to GMVIS Supercede: This bulletin is being revised to remove the graphic, update the Parts and Correction information and add information to advise a customer. Please discard Corporate Bulletin 08-06-04-054 (Section 06 - Engine / Propulsion System). Condition Some customers may comment on the malfunction indicator lamp (MIL) being illuminated and an Engine Power is Reduced message being displayed. The technician may observe DTC P0101 set as current or in history. Cause This condition may be caused by snow being ingested into the air cleaner housing and accumulating in the air cleaner element, resulting in restricted airflow into the engine. Correction 1. Verify the condition by questioning the customer as to when the condition occurs (such as during or right after a snow storm). ◊If the condition occurs as described above, proceed to Step 2. ◊If the condition does not occur as described above, refer to Diagnostic Trouble Code (DTC) List Vehicle in SI. 2. Remove the air cleaner element. Refer to Air Cleaner Element Replacement in SI. 3. Inspect the air cleaner element for the following conditions: 1. Packed snow 2. Frozen ice 3. A soaking wet condition that would indicate previous snow ingestion 4. Excessive debris and contamination as a result of the ingestion ◊If any of the above conditions are observed, replace the air cleaner element. Remove any snow or ice that may have accumulated in the air intake duct. Note Winter covers for trucks that are equipped with the Duramax(TM) Diesel Engine are included with vehicle orders that ship to the following areas: All of Canada, and the following states: Alaska, Colorado, Idaho, Maine, Michigan, Minnesota, Montana, New Hampshire, New York, North Dakota, South Dakota, Vermont, Wisconsin, Wyoming. These vehicles should not need a new cover. 4. Install the grille opening section ONLY (if using the 2 piece cover) of the winter front cover following the usage guidelines provided in the Owners Manual for the appropriate type winter cover. ◊If the customer does not have a cover, obtain and install the grille opening section ONLY, GM P/N 25822811 (GMC) or GM P/N 25822812 (Chevrolet). 5. The grille opening cover MUST BE installed to ensure a complete repair, BEFORE ENCOUNTERING SNOW. This repair allows warm air to be circulated into the air cleaner. Additional Information to Advise Customer Important If the vehicle is driven in a snow storm before installing the winter cover and the customer chooses to resolve the issue, they must follow this procedure using the following steps: 1. Remove ANY ice or snow that may have accumulated in the air intake duct, BEFORE REPLACING the air cleaner element. 2. INSTALL the winter cover BEFORE continuing to drive the truck. 3. Turn OFF the ignition, and all electrical accessories and components. 4. Remove the key from the vehicle, THEN open and close the door. 5. WAIT for 2 minutes to allow the (ECM) to power down. This can be verified by watching for the instrument panel cluster (IPC) gage needles to drop slightly. 1. Allowing the ECM to power down will let DTC P0101 revert to a History DTC and the vehicle should return to full power if the issue has been eliminated. 2. Advise the customer to take the vehicle to the dealer as soon as possible to verify the condition has been eliminated.

https://www.dropbox.com/s/85g3uzm3ax5vtk6/rad-10-27.gif?dl=0

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete.

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