USAFPROUD

I just wanted to put it out there for anyone who wants to delete the DOD or AFM mode on their Gen 4 LS engines, that disabling the mode with a tuner, or plug in device doesn't prolong the life of your engine. Why am I posting this? little back story, I bought my first truck, a 2008 Silverado 1500 with the 5.3 LMG with 89,000 miles. Truck was well maintained with regular oil changes. I personally went through and checked everything on this truck. Three months in, I started my truck and it sounded like someone dumped a can of marbles into my cylinders. The truck was perfect up to this very point. The noise subsided and never did it again, so i brushed it off and plugged my HP Tuners in and disabled DOD. fast forward a month in, I unscrewed my oil cap with the engine running because I was showing my friend how blow by works and how to test for it. I was awarded with a horrible knocking sound, that when I put the cap back on, wasn't audible. The knocking was only audible with the cap off. So I pulled the valve cover to find two lifters bone dry and not pumping up. I decided to pull the rods and try to clean the lifters but no avail. Three weeks later, the engine began to misfire and the lifter collapsed completely. I then proceeded to angrily tear the engine apart and found the lifter spun in its bore eating the camshaft lobe. I replaced everything, did a DOD delete, LS7 lifters and rods, a camshaft from a 4.8.. and sold the truck. Once people found out I had knowledge about the issue, i was doing cam shaft and lifter repairs monthly. This issue is incredibly widespread. I even started charging people to disable their AFM as precaution thinking if I turned it off, they wouldn't have issues. Even though turning it off often solved oil consumption issues, I found that most of the vehicles I disabled DOD on came back with collapsed lifters, and pissed off customers. Most of the lifter issues have been on 2007-2010 chevy trucks and suburbans with the iron and aluminum block engines. A super common engine to quit first is the LMG. I've seen several of these including my own give up in my area. The first signs include a knocking noise only heard under the oil cap or driver side valve cover. The oil pressure usually remains steady and doesn't fluctuate if the engine has issues. Mine held a 40 psi idle before and after the lifter failure. The aluminum block often fails on the no.1 lifters and will throw oil pressure codes, clog the VLOM filter under the oil sending unit. Usually a oil pump is to blame for these issues but I've seen lifters do it too. I have a few tips for anyone taking thi project on:

1. Set aside three days for the project. It isn't hard, but it is a involved job.

2. Tune out DOD, see if your issues go away, and if they do, Great! If not, drive it until you are ready to do the delete. It will save you time having the delete done in the ECM

3. Never reuse headgaskets or head bolts. Don't ask me how I know

4. Verify if your engine has VVT or not. Most trucks after 2009-2010 have it. most shops offer the kits to delete AFM on VVT engines and people wonder why their kit doesn't work on their non VVT engine.

5. If you have the VVT engine, you have the single bolt cam with phaser and if deleted you have to buy a three bolt cam and adapter. Purchase LS7 lifters, valley plate, springs, and rods for your delete. AMS racing from Bossier city LA has a delete kit with everything you need including cam: https://www.amsracing.net/products/c...dod-delete-kit I'm not their sponsor and don't endorse their products, but it's the kit I've used with excellent results and they are literally a mile away from me.

6. If you have a non VVT engine and you go sourcing parts yourself, I advise you stick with LS7 parts. You can replace your cam in the non VVT engines with a aftermarket cam, or the stock cam shaft that comes in the LQ9 6.0L or Gen 4 4.8L engines. If you want a mild cam that will interface well with the A6 or A4 trans, a LS3 cam will wake your engine up without needing to tune.

7. Dont retain DOD! If your lifters fail, and you replace them, expect them to fail again. The VLOM is known to fail and often cause these issues. The VLOM is basically the valley cover but has the solenoids for the V4 mode lifters. If you are doing warranty work, and deleting isn't an option, it is highly advised to replace the VLOM with a genuine GM module and replace its filter under the oil sending unit. Also, never replace just the lifters that collapsed. You must replace all of them, especially if you put a new cam in. You can use the stock engine cam if it isn't ruined, but again, replace ALL the lifters!

8. If you don't have any symptoms of failure, keep an eye out. If you can catch the failure in its early stages, you can usually get away with just replacing lifters. It does take some time to eat the cam and put metal in the engine, my truck knocked for 4 months and I was able to catch it.

9. This isn't a very expensive job. If you know to to source the lifters, gaskets and trays, and get a use cam, you can easily do the job for 400 dollars.


Another note is that I've seen vehicles with P0521 sending unit codes that go away for a few days after replacing the sender. This code is usually caused by a blocked VLOM filter under the sending unit, in its passage. (See TSB below) it's usually caused by sludge in the engine and issues with the VLOM. A good cleaning
Will usually resolve the issue, but should it arise, it's a common issue I see with trucks that had their lifters or cam replaced and the customer opted out to replace the VLOM.

TSB For the VLOM filter: https://www.obd-codes.com/pdf/gm-tsb-pip4786c.pdf


Excellent rebuild thread: SilveradoSierra.com ? How to delete your AFM / DoD and/or VVT : How-To Articles

What my engine sounded like when it's lifter collapsed, (LMG)

I wish I could say there's a cure for the issues but no amount of religious maintenance or driving like a old man can prevent this problem. It's not a matter of if, it's when. My customers range from lead footers (like myself) to grandma who takes her Cadillac to church every weekend. I've seen most of the lifter issues pop up at around 90,000 -120,000 miles. If you make it past 130,000 then you've probably got a good engine, be nice to it and you might not have an issue. I can say that 5 people on base right now have the issue and don't even know it. I just listen to them start their trucks in the morning and kinda cry inside when I hear their 5.3 sound like a diesel.

Johnfortunato

I need to turn my DOD v4 mode off on my 5.3.. do you know where this can be done? I have a snap-on solus ultra scanner could it be done with this?
thanks

BTC1984

2008 Suburban 157K miles. Runs great. Oil pressure sending unit goes bad. My son drives it for about 200 miles with the sending unit bad. Finally I take the truck from my son get it to the shop and my mechanic replaces the Oil pressure sending unit and also replaces the screen under it, says the screen was full of gunk. Says he did a test drive and it was fine. He brings it back to the shop after the test drive to charge my AC unit, then it starts to mis-fire in cylinder #5. He says due to AFM the lifter is stuck. The mechanic and many other people said changing the Oil sending unit has nothing to do with the stuck lifter. But I just read the screen under the unit is for the AFM oil. So if that's true the two systems are very much connected. Your thoughts?

The Shop

AFM cylinders are 1 and 7 and 4 and 6. so missfire on 5 is unrelated. we have seen plenty of bad lifters on cylinders 3 and 5 with bad rollers.

The Shop

no a solus cannot turn off afm. you will need hp tuners or other editing software to do this.

ccalim99

You use AMS DOD Delete kits...I have an 07 5.3l and ordered the kit.
Underneath the valley cover is completely empty from AMS compared to the stock one which has solenoids. I know they arent used, but do I need to move anything from the old one to the new valley cover sent from AMS? Or is it okay to install as sent?

Christopher Talbert

Hey thanks for the post. I just performed the same swap on a 2009 Silverado 5.3L LT. Purchased a AFM DOD Delete Kit with Oil Pump for 2007-2013 GM Chevrolet 5.3L Truck SUV from AMS Racing in Bossier City. The kit came with a cam with a single bolt. The truck ran great when starting and driving short distances. After my first long drive (45 min) I noticed a ticking/knocking noise under load and high idle. Not sure what my problem could be. I took my time to install everything. I called AMS and they offered to replace the liters. Have you had this issue? I also sent in my ECU to be reprogrammed. On a cold start the truck starts nice and quiet.

Wiskies garage

Hello, would a bad VLOM throw P3400 CODE? I replaced lifters after failure and now getting this code. Thank

Mickeyg316@gmail.com

have you ever replaced all lifters and cam, only to have a lifter collapse again after thousand miles?

johnmr12

Here is my experience. My 2015 silverado 5.3 with the "brilliantly" designed AFM system got a cylinder misfire code. It was cylinder 4. I had no idea what AFM even was at that point, so I did the typical troubleshooting steps. I swapped out the plug, then I swapped the coil pack with another cylinder, then I removed and cleaned the fuel injector. Nothing worked, so I pulled the valve cover and saw my intake valve was not functioning. Thats when I started researching the problem and learned all about AFM. I had noticed that the truck would burn about a quart of oil every few months, and I never could find a leak. So I took it to my mechanic, and he found that the cheap *** plastic lifter tray had spun the lifter. At that time he said the camshaft was ok, so he replaced the trays and lifters on the passenger side. I bought a device that plugs into your diagnostic port and disables the AFM. I ran for about 2 months and the exact same thing happened. My mechanic told me he was wrong about the camshaft being good, so it ate the new lifter. At that point he said since I needed a new camshaft he would have to do both heads. He is probably the most honest mechanic I have ever met so he agreed to only charge to do the drivers side and he would do the labor on the passenger side free. I decided at that point to get rid of AFM altogether so I bought an AFM delete kit, which came with everything to eliminate the AFM. But, you have to reprogram the control module so it doesn't know about the AFM. I found a guy in Missouri, sent him my module, and he programmed it for $50. My mechanic charged me about $1500, the delete kit was about $600. I had paid about $1500 for the first repair so if you do it right the first time, it should cost around $3,600. If it hasn't had any trouble yet, I recommend spending the $200 for the device that plugs into your diagnostic port. It prevents the AFM lifters from collapsing. By the way, since I removed the AFM crap, my truck no longer burns oil.