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Chevy Silverado and GMC Sierra Active Fuel Management Problems



  • KCRamKCRam Mt. Arlington NJPosts: 3,516
    Since your issues don't involve the Active Fuel Management system, please post your engine question here: Chevy Silverado and GMC Sierra Gasoline Engine Problems and the suspension question here: Chevy Silverado and GMC Sierra Suspension and Ride

    kcram - Pickups/Wagons/Vans+Minivans Host
  • Were the problems with AFM resolved for the '09 and later models? Thank you.
  • minismomminismom Posts: 4
    I purchased a l500 sierra (l989) as a farm truck - this is what it is doing - it does not accelerate after stopping at an intersection - stalls & won't restart - have changed distributor & brians, plugs & wires, new battery, oil & gas filter - also when it does restart it belches black smoke and smells like gasoline - does the same thing when it is in reverse - sucks up gas like crazy - I don't want to have to have the tank pulled to change the fuel pump, screen or sending unit - the check engine light is on also - mechanic told me it was the catallyc converter - other than that it is a nice truck & the body & frame is in great shape for a truck that age - thanks for any help
  • obyoneobyone Posts: 8,054
    Sounds like you have a plugged catalytic converter. However, that may be the result of your problem rather than the cause. Since you stated that they have changed the brains, the other cause could be a bad fuel pump. The belching of black smoke and the smell of fuel is exactly what killed your catalytic converter. Your plugs are probably fouled at this point also.

    If you worked on the truck you could probably get away with $600 in parts to fix your truck. If using a mechanic you're looking at over $1000 to fix it. A replacement catalytic convter is close to $300 wholesale. Not sure if the truck is worth saving.
  • cnw20cnw20 Posts: 4
    I have an 07 Silverado with AFM and 5000 miles ago (I currently have 75K on it) the dreaded "add engine oil" light came and I had a dry stick. I took it to the dealer who replaced the gasket around the oil filter (you could see the oil accumulation on the bottom of the frame but surprisingly not a drop on my driveway - they told me it only leaked out at high speeds?) and added sealant to the bolts. Well 5000 miles later I have the same problem and am going back to the same dealer tonight - I'll keep you posted. Hey maybe if they fail to fix it this time I'll let it seize up and hopefully get a new engine?
  • gmcustsvcgmcustsvc Posts: 4,252

    I apologize for the problems you are experiencing with your vehicle. Please keep us posted on any information from the dealership.

    Thank you,
    Caron, GM Customer Service
  • cnw20cnw20 Posts: 4
    edited August 2011
    I just called Chevy at 800-222-1020, didn't get a case # yet, and they will contact the dealer who "tried" to tell me that using 3 quarts in less than 3000 miles is normal - I told them when I dropped off my truck last night do NOT tell me this and they called today and did. There's many TSBs all over the internet on this lousy engine and GM knows it - I plan to fight this to the bitter end. If in fact, as posted by u earlier, that these engines are supposed to burn a quart for every 2000 miles that only means one thing - GM is again making garbage like they did in the 70s!
  • gmcustsvcgmcustsvc Posts: 4,252
    Can you please keep me posted on what happens with Customer Assistance? I apologize for your frustrations. I look forward to your update.
    GM Customer Service
  • i got a brand new vortex max in 08 3 days after i got the truck i took it to the dealer to tell them about the knocking noise coming from the engine when the truck is running and a loud clicking sound when i make a u turn but the dealer was out of business so i took it to a other dealer they told me it was normal so i keep on driving until it became worst about 16,000k again they told me its normal then my friends told me its not normal because they all have the same trucks so about 35,000 i took it to a different dealer and they all said its normal mean wile i had lots of other small problems seat belt jam up door locks not work cruise control broke heated wind shell wipers not working and traction control broken so i drove the truck the ways it was until the engine blew up at 101,000k just over the warranty they fixed it under good=will repair then the same engine blew up 3 weeks later at 104,000k the guy from gm told me they would replace the truck or buyback the truck and had me take it to a dealer to confirm it was the engine so i did and some one else said they only gonna fix it again so far it cost gm over $20,000 to repair this shi# engine and i had to many things go wrong so i am pissed i will not expect this truck back at all and i demand a replacement truck and buyback this truck if not i will contact bbb about the and make sure non of my family or friend ever buy a gm product [email protected]
  • gmcustsvcgmcustsvc Posts: 4,252

    I apologize for the problems you are experiencing with your vehicle. Do you currently have a case set up with GM Customer Assistance? If so, could you please email me the case number?

    You can get my email by clicking on gmcustsvc.

    Thank you,
    Caron, GM Customer Service
  • ok caron i do have a case number and they are not doing anything. john the one who was handling my case assured me i would get another truck cause its obviously a lemon and now they are re nagging on they words. don't you guys record your phone calls? anyways it is noted in my account what he said. i dont wanna get mad but gm is screwing me. it cost me close to 42,000 dollars for this truck. i put 6,700 down and i am paying 800 for a broken vehicle. i know gm buys back their problem trucks. i want them to buy back my truck or i have no choice to go the arbitration route. please help. the case number is 71-969290786
  • As it has been a while since my original Rant regarding my 2010 silverado and AMF . On the 5th return to the dealer, they determined it was cam shaft failure. After two days in the shop, they claimed a error msg. Showed up out of the blue stating the #1 plug fouled. I don't about you, but this is not my first run around with GM and the excuses for not doing the approbate repaired is getting old. so they replaced the plug and sent me on my way. Couple of weeks later the plug fouled again, this time it was asked with oil. They contacted GM for the third time. This answer was to pull the heads and remove the litters well long story short, on day two a different tech at GM to the dealer to replace the #1valve guide other then the valve cover being pulled pulled nothing else was checked. Don't know if I mentioned this before, my neighbor
    2010 at 18000 miles had engine rebuilt, cam shaft failure... Sounds like a common problem. Well the end of this story is the day after I got it back I traded it off at a 30%loss guess the value of
    GM's are not what they used to be. Replaced it with a 2011 chevy camaro. Dealer stated there are some issues ie... Exhaust system. But "GM" is refusing to pay for the repair as they state that is inherent to that type of system which is there because of the AFM. I think it time that GM stops trying to B.S. The government for the bad fuel milage and charge the penalty like Dodge does for not getting within the fuel guide lines. Thanks GM for finally getting it through my head, this is my last run around with a GM product as this company has no interests in the satisfaction of its consumer. On a positive note I have owned 78 camaro, 84 camaro four chevy trucks and my last 2011 camaro up to "2010 I had a good run.
  • My 2010 silverado was diagnosed by dealer cam shaft failure after intervention from GM they replaced # 1 cylinder valve guide. That was the sixth attempt at a repair. Still didn't address the cam shaft. GM won't even take the word of the mechanics working on the trucks. My neighbors truck had engine rebuilt at 18000 miles, "camshaft failure" seem like GM Is trying to avoid a recall. I dumped the lemon
  • jbt4jbt4 Posts: 1
    I have an 07 GMC Sierra and I have also been having problems with oil consumption. At about 65,000 miles my "low engine oil light" came on. It had only been 1800 since my last oil change, there was no oil visible on the dip stick. I call the dealer where I purchased the vechile and they advised I bring it in as soon as possible. They changed the PCV valve, Manifold gasket and few other things. Everything was fine for two oil changes then the same problem started happening. I have an appoinment to bring my truck back to the dealership Monday (this will the 6th time) b/c the low oil light came on again and this time it had only been 1500 miles since my last oil change, I'm starting to think this problem will never be fixed and my 100,000 mile warrenty is all most up. Does anyone if there is a fix for this problem? Thanks
  • stumpman2stumpman2 Posts: 3
    edited August 2011
    I wonder if you bypass or reprogram the AFM where it stays in 8 cyl mode all the time if it will help? A friend who is a GM mech said they were having issues with replacing pistons due to this. said it wasn't lubing the cylinders properly that weren't firing/running when in 4cyl mode Just wondering if it will help or not?

    I have an 07 with 43,000 miles and so far no problems. Do all these engines have this issue after so many miles or just some of them?
  • gmcustsvcgmcustsvc Posts: 4,252
    I apologize for your frustrations. Can you please email me with your complete contact information, VIN, current mileage, and involved dealer? I would like to set up a case for you with GM Customer Assistance. This will document your concerns and that you are experiencing them under warranty. Has the dealer involved technical assistance? If not, I would recommend asking them to do so. I look forward to your email.
    GM Customer Assistance
  • chuck1chuck1 Posts: 1,405
    If you put it in manual mode and shift it to 5th - the AFM will never come on. You can try that.

    There is absolutely no truth to the fact they are replacing cylinders due to AFM.

    Read how it works-it's a very simple system-
  • stumpman2stumpman2 Posts: 3
    edited August 2011
    Mine is an 07 and doesn't have a manual mode that I know of.....Not sure why he would lie being it didn't have an effect on me. Said there were 5 in there being worked on or had been worked on. Said something about not getting enough lubricant to the cylinders or something to that effect.
  • chuck1chuck1 Posts: 1,405
    There are hundred of thousands of these motors on the road when you include all models of GM cars....

    Do a google search - see for yourself. I guess maybe a few have had problems. I couldn't find anything on a google search.
  • Read on other GM boards many people are having issues with 07NBS and newer trucks using a lot of oil between changes and having engine troubles. Not hard to find at all if you look.
  • chuck1chuck1 Posts: 1,405
    It's not a lot of trucks. I understand, if it's yours its important. BUT, very few trucks are having oil consumption issues. I have looked at those other boards AND the NUMBER OF POSTERS who claim they are having issues.

    The vast majority are happy.
  • Had it back to the dealer twice and its still using oil. They overfilled it for the first consumption test so after it burned that up I'm on my second consumption test now. Once I saw your (or another service person) post about a 5.3L AFM with under 36K miles should use 1 quart every 2000 miles I decided to trade it in and never buy a GM vehicle again. I have cars and trucks that had over 100K miles that NEVER used any oil between changes. When will GM finally realize that this engine is a lemon and do right by their customers? My guess - never.
  • I have a 2007 GMC Sierra SLT Crew Cab with a 5.3 AFM Motor. The day I drove this truck off the Dealer Lot in Jan. 2008 brand new it had multiple warranty issues.
    1.)Rear Power Window did not work.
    2.)Drivers Side Seat Motor did not work.
    3.)Whole Carpet Kit had to be replaced because of defect causing it to fall down under the brake and gas petal. They took out full interior trim and broke all clips that hold all plastic pieces in place.
    4.)Recall for Window Washer Heater. Causing Trucks to catch fire. Took it out and dissabled it.
    5.)Stering Wheel Control Lights would not work.
    6.)All 4 Door Handles Broke, almost off the truck.
    7.)Oil Dip Stick Tube broke away from the block at the bolt.
    8.)A/C Wire Harness to the fan blower motor.
    9.)Battery Replaced
    10.)Oil Consumption with AFM. They opened up the motor and put some coller on the AFM valve.
    Not even my first oil change since having the work done and it consumes again with the message coming on Low Oil.

    Local GMC Dealer " Phillips Buick GMC " Fruitland Park, Florida has been the ones to perform the repairs. On the second time in about the oil consumption I am being given the run around about it not being a problem. And they want to do a 1000 Mile test VS the standard 2000 mile 1 quart test. Even after the valve coller work to repair this problem, it still exists at the same rate.
    Along with the consumption issue I also noticed that my gas mileage went down. I complained of this as well. I haven't got more than 15 MPG on Highway almost since new. Sticker says 16 MPG City, 21 MPG Highway. After they did the work I got about 2.5 MPG more for about 6 tanks of gas. Then the gas mileage droped again and the oil low message came on again.

    I had such a problem with an aftermarket warranty that the original GMC Dealer " Fountain Auto Mall " Orlando, Florida,sold me. They sold me a $2,400 warrany that when I had to use it at Phillips GMC I was told that Phillips GMC would not honor it even though I bought it from another GMC Dealer. I also found out that the second warranty that I was sold ONLY provided the exact same coverage that the manufacture sold with the truck. 36,000 bumper to bumper and 100,000 drive train. I finally called the aftermarket warranty company and got $800 prorated back to me.

    I am currently consulting an Attorney for action against GM for the Lemon. And the original Dealer Fountain Auto Mall GMC for their deceptive practice of the useles aftermarket warranty.
    The firm that I am using is Krohn & Moss, Ltd. they will take a case for free if it is legit.

    I'm interested in any feedback anyone may have.
  • chuck1chuck1 Posts: 1,405
    edited October 2011
    I had such a problem with an aftermarket warranty that the original GMC Dealer " Fountain Auto Mall " Orlando, Florida,sold me. They sold me a $2,400 warrany that when I had to use it at Phillips GMC I was told that Phillips GMC would not honor it even though I bought it from another GMC Dealer. I also found out that the second warranty that I was sold ONLY provided the exact same coverage that the manufacture sold with the truck. 36,000 bumper to bumper and 100,000 drive train. I finally called the aftermarket warranty company and got $800 prorated back to me.

    I bought my truck and the dealer tried to sell me a third party warranty. The first question one should ask is "Is this a GM warranty?" Most of these third party warranty companies are "fly by night" and I don't blame the second dealer for not accepting it. There is a good chance they would not be paid by the warranty company. Dealers sell what makes the most money for them, not what is best for you. Good luck with the rest of your problems.

    BTW-you really over paid for that warranty.
  • Adding sealant to the bolt helps in some way, but the actual point upon which the leak comes out is in the gasket. I don't know exactly how does it happen after all you have firmly held the gasket. High speed, yes it is. It actually an aspect contributory to the leak. In my case, the built in turbo manifest such actuation. If you could have an engine less than what you are expected to pay off for the replacement, then go for it. But for me, I'd rather have it repaired.

    Making the impossible possible!
  • string2string2 Posts: 71
    I feel like I have been ripped off by Chevrolet. I bought A 2011 Silverado Crew Cab two months ago. "The Active Fuel Management" system won't drop back to 4 cylinders at cruising highway speed (70 MPH) on flat level highway, unless going downhill or if I take my foot off gas. This is with or w/o cruise control turned on. AFM system will work for short distances at around 45 MPH. I have 2,700 miles on it now and it has never worked at highway speed, as advertised and explained in the Owner's Manual. Took to two dealers. There is no trouble code, but the computer was changed out. Still no improvemant at all. Contacted Chevy service assistant. She talked to dealer and said without a trouble code there is nothing wrong with it. She said drive it, it might get better if I put more miles on it. She said her decision was the final say on the problem. Checked videos on Utube and found a demo showing 95 miles on same truck as mine working just like the manual says it should. I am HACKED OFF @!*&#
  • cnw20cnw20 Posts: 4
    Once GM stated publicly that using 1 quart of oil for every 2000 miles is normal I sold my Silverado and since I do not a pickup anymore bought a 2012 VW Sportwagen TDI that gets 45 mph and I haven't looked back.
  • chuck1chuck1 Posts: 1,405
    The AFM will only come on at 6% or less throttle. It's not coming on if your driving 80plus on the's not going to happen.
  • string2string2 Posts: 71
    Thanks for the info Chuck. I have looked at the Demo videos on utube showing how AFM works. It showed V4 mode working as it should in cruise control at 72 MPH on level highway. Stayed in V4 mode about 3-4 minutes until starting uphill. Do you know if there is any adjustment on the throttle, that may be the problem? Thanks again!
  • chuck1919chuck1919 Posts: 176
    From what you are describing the road was probably level or perhaps slopes down a bit. It doesn't take much for it to "tune out" of 4 cyl mode because 6% is not much throttle.

    Even 80 on a flat road will not get you in 4 cylinder mode except going down a hill.

    I don't think GM should have ever put the V8-V4 indicator on the dash. Just let it go about it's business and nobody knows the difference. JMHO.
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