Any Mechanics here? Need assistance

cattleman99

cattleman99

Snyder Precision LLC
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Mar 28, 2018
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#1
I have an 08 Silverado 1500 with a 5.3 Vortec in it. Flex fuel and 4WD. I’ve been noticing a really rough idle lately like a cylinder was misfiring, so I got the truck scanned. Cylinder 7 was misfiring, so I changed spark plugs on that bank with no success in solving the issues. So I just changed the injector, still a rough idle, almost getting worse.

Now, I’m getting another check engine light, and two new messages being “service stabilitrak” and “service traction control”.

Any tips or pointers? These messages and the check engine light aren’t always on, but they come on and go off quite often. Sometimes the check engine light flashes so I really don’t want to drive it.

Thanks!
 
#2
Had an older 5.3 in a Tahoe, coil pack and plug wire were bad on one cylinder.
I don’t think LS series engines suffer from the old small block cam rounding off sydrome? Someone should be able to read the code it throwing?
 
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#3
Expert684 said:
Had an older 5.3 in a Tahoe, coil pack and plug wire were bad on one cylinder.
I don’t think LS series engines suffer from the old small block cam rounding off sydrome? Someone should be able to read the code it throwing?
Click to expand...
I replaced plug wires, thing a coil pack would do the trick?
 
#4
Probably a coil pack, do you have a gap style spark tester? If not move coil to different cyl and see if misfire code changes to that cyl. Also visually inspect the coil pack usually they arc out and there will be shit stains on the plastic there it was arcing. Also the stabilitrac and trac light is from the check engine light fix that and the others will go away.
 
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#5
ajwcotton said:
Probably a coil pack, do you have a gap style spark tester? If not move coil to different cyl and see if misfire code changes to that cyl. Also visually inspect the coil pack usually they arc out and there will be shit stains on the plastic there it was arcing. Also the stabilitrac and trac light is from the check engine light fix that and the others will go away.
Click to expand...
Unfortunately I don’t have permission to take the scanner, and I don’t want to drive the truck how it is. I’ll run and grab a coil pack and see if it works
 
#6
Before you buy a coil ( move it around with another one( 1 to 7 and 7 to 1) for another and see if the code changes. It will single out the coil pack. It might be a 02 sensor too. So if you swap two packs around and code dose not change then try and swap the 02 from side to side and see if then the code changes. It's a little work but will safe funds in the end.

I'm betting the other is

4WD Actuator my 04 said the same code.
 
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#9
BigDaddy0381 said:
Before you buy a coil ( move it around with another one( 1 to 7 and 7 to 1) for another and see if the code changes. It will single out the coil pack. It might be a 02 sensor too. So if you swap two packs around and code dose not change then try and swap the 02 from side to side and see if then the code changes. It's a little work but will safe funds in the end.

I'm betting the other is

4WD Actuator my 04 said the same code.
Click to expand...
I don’t have a scanner on hand to read codes if I switch coils around
 
#11
2ndamendfan said:
Stabil track and traction control are functions of the engine computer. Those get deactivated when engine is not running right.

Fix the miss and those will be fixed also.
Click to expand...

Yep - if you start throwing misfire codes, then traction/stability control can no longer function due to uncertainty in engine torque estimation.

Swapping around the coil is a good starting point. If that doesn't yield any clues, it's time to do a compression or leakdown test on that cylinder to see if you've got a dead hole. The most likely cause is a collapsed lifter.
 
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#12
If you've already replaced a plug and injector your next bet is the coil. Remember that if you didn't reset the CEL after part replacement the computer may not immediately see that the issue is fixed. If you don't have a scanner to clear the DTC, I could disconnect the battery and clean the throttle body while it sits for a few minutes. That will clear the computer's short hold memory and cleaning the TB will make the computer relearn the idle parameters when you start it back up. After a coil you should look at an intake gasket, although it would be rare to see the computer throw a misfire code without a companion "system lean bank X" code as well. Best of luck
 
#16
Scan tools are not expensive - one can be purchased for about the cost of an oil change. If you can afford to put gas in the tank, you can afford a scan tool. And if indeed you've got a collapsed AFM lifter, then the cost of a scan tool is about to become the least of your worries.
 
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#18
E. Bryant said:
Scan tools are not expensive - one can be purchased for about the cost of an oil change. If you can afford to put gas in the tank, you can afford a scan tool. And if indeed you've got a collapsed AFM lifter, then the cost of a scan tool is about to become the least of your worries.
Click to expand...
Hope it’s not lifters.. I’ll be getting a afm disabler very soon
 
#20
If you had a collapsed lifter, you would hear the ticking without a doubt. do the coil pack swap for sure, they go bad. Get a new one from a scrap yard. then if that doesn't work, leakdown test on each cylinder for sure. a compression test gauge is cheap too about $40. If you have an Oreily's auto parts store around you, they loan all this stuff out.
 
#21
If you've got a dead lifter, then it's a bit late to be disabling AFM. But it's a great time to rip out all the AFM hardware while you're in there replacing the lifter.

Hopefully your problem lies elsewhere. Coils and wires are easier to repair. Don't rule out the injector on that cylinder, although it's kinda unlikely to be the problem.
 
#22
Sometimes with stuff it's cheaper to take it to the stealer and let them diagnose the problem, and you take it home and fix it, VS throwing parts at it. Trick is to know your limitations and when to take the gamble.
 
#26
You can buy the scanner on ebay it's a elm327 for cheap like $13 the down load tourqs app for $5 or so and you can read and clear the codes. Shoote a call tomorrow if any questions. I use to build LS motors and this was an easy way to figure things out with out charging 500 to run it thru the laptop programers I used hp tuners

Screenshot_20190904-214356.png
IMG_20190904_214419737.jpg
 
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#29
BigDaddy0381 said:
You can buy the scanner on ebay it's a elm327 for cheap like $13 the down load tourqs app for $5 or so and you can read and clear the codes. Shoote a call tomorrow if any questions. I use to build LS motors and this was an easy way to figure things out with out charging 500 to run it thru the laptop programers I used hp tuners

View attachment 7142352View attachment 7142353
Click to expand...
Due to a time restraint I can’t really order one and wait. If I don’t like the one I buy tomorrow I’ll give it a go though
 
#31
gunman_7 said:
If you had a collapsed lifter, you would hear the ticking without a doubt. do the coil pack swap for sure, they go bad. Get a new one from a scrap yard. then if that doesn't work, leakdown test on each cylinder for sure. a compression test gauge is cheap too about $40. If you have an Oreily's auto parts store around you, they loan all this stuff out.
Click to expand...
It does have a very faint tapping sound
 
#36
Expert684 said:

Take a look at this?
Click to expand...


Guy obviously isn't familiar with AFM Chevy's our he'd be pulling the lifter before doing a cam. More than likely either the lifter or actuator failed and his customer is going to get ripped off for an entire rebuild before he's done.

I actually don't know of anyone that has ran a cam flat unless they ran out of oil. Roller lifters just don't wear cams.
With the vortec start in 96 everything has been roller lifters because flat tappets don't like low zinc oils and catalytic converters don't like high zinc oils. Also the reason you see so many earlier sbc with flat cams now. Have to run diesel oil or hot rod oil with higher zinc to lubricate the lifter to cam sliding surfaces.



I own 4 Chevy's, and have to drive a Ford for work. The Ford is in the shop every 25k miles, my Chevy's keep on going with oil changes. Triton motors have their cam phasers (about $3k to have a shop fix) and spark plugs, Chevy's have their AFM (no idea on $ because I haven't had to screw with one yet).
Only Chevy with less than 225k miles is my wife's car, all 3 trucks are 225k-400k miles. Work Ford has had $16k in work done to make 150k miles.

Doesn't matter the brand, sometimes you get a bad one.
 
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#38
I would start with the inverted overthruster . Sometimes the muffler bearings in the over thruster go bad causing the chrome fullopium tubes to leak . You also wanna check your flux capacitor . You will need miro encabulator to do this . Spraying some Hanna Kanna. Fran on the capacitor may help . Let me know how you make out .
 
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#39
BigDaddy0381 said:
You can buy the scanner on ebay it's a elm327 for cheap like $13 the down load tourqs app for $5 or so and you can read and clear the codes. Shoote a call tomorrow if any questions. I use to build LS motors and this was an easy way to figure things out with out charging 500 to run it thru the laptop programers I used hp tuners
Click to expand...

2nd this option. I picked up a bluetooth module for $8 on Amazon and use the Torque Pro app and it's done exactly what it's supposed to do. Spits the code out and shows basically every bit of data going through the computer.
 
#40
chevy_man said:
Doesn't matter the brand, sometimes you get a bad one.
Click to expand...
I worked out of a truck for most of my life before retirement. We had Fleets full (over 200 trucks at one time) of IH, Ford, Chevy, Dodge, an Rice Burners. O&M cost vs Down time are real numbers not made up out of the blue. We did not baby, or abuse them, some were street only others off road 90% of the time an everyone loaded to max GVW & CGVW all the time. As they were just a tool for the task at hand. Nothing beat IH back in the day, Nothing. Then came Ford, Dodge, Chevy an Rice in that order. When IH went away, it was Ford, Dodge, Chevy & Rice. Years later it was still the same. In 2004 the brains to be looking at upfront money, vs life cycle money (front + O&M an resale) went heavy on Dodge an Chevy, huge mistake. The Dodge had weak transmissions, brakes, Steering, Diffs an everything electrical. The Chevys required a Wrecker on standby if you went off road the engines an trans were major issues all the time. These issues cost no only us money but our customers heart burn do to down time.The Rice burners were now as tough as the old IH's in Life cycle money. When I retired in 2009 it was Ford, Rice, Dodge, then Chevy.
All these trucks were used as tools, an every dollar spent upon them was accounted for. I even had a Dealer tell me once when I was in for that POS 6 liter Diesel, the reason we were having so many issues under warranty is because we used all our trucks to rated specs. We never had a 8K -21K CGVW truck that just pulled a bass boot or took the kids to school. Working truck are just that.
Now all that said, much depends upon your drivers an the quality of local service, but if it's a POS for the task from the drawing board the life cycle money will prove that out. Every one of the trucks had/have strong points an all of them have weak points, but at the end of the day it's life cycle money that is like a bullet hole on target, it does not know how to bend the truth.
 
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#41
cattleman99 said:
Guy obviously isn't familiar with AFM Chevy's our he'd be pulling the lifter before doing a cam. More than likely either the lifter or actuator failed and his customer is going to get ripped off for an entire rebuild before he's done.

I actually don't know of anyone that has ran a cam flat unless they ran out of oil. Roller lifters just don't wear cams.
With the vortec start in 96 everything has been roller lifters because flat tappets don't like low zinc oils and catalytic converters don't like high zinc oils. Also the reason you see so many earlier sbc with flat cams now. Have to run diesel oil or hot rod oil with higher zinc to lubricate the lifter to cam sliding surfaces.
Click to expand...

While it's not common to wipe a cam lobe on any modern engine with roller lifters, it's also not impossible. GM GenIII and GenIV engines use plastic lifter "trays" to keep the individual lifters from spinning in the bores (as opposed to the metal "dogbones" on GenI and GenII roller-cam engines, or the link plates on high-perf aftermarket roller lifters). If those trays fail, then the lifter can spin in the bore, and this tends to hurt the cam lobe. It's also possible for the needle bearings in the roller to fail, but that's fairly uncommon with stock valve springs.

All that being said, you are correct that the problem is far more likely to be a collapsed lifter than it is to be a defective cam. It's just that a good mechanic needs to take a peek at the cam lobes while the lifters are out, because going back to do that job a second time would be rather painful.

Doesn't matter the brand, sometimes you get a bad one.
Click to expand...

I generally hold the GM GenIII and GenIV motors in high regards. But the AFM feature has led to problems that simply don't exist on the simple versions of this architecture. It's yet another good example of stuff that will probably work fine through the warranty period, but will also cause headaches for those of us that run vehicles out to a quarter-million miles and beyond.
 
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#42
Update. I plugged my new scanner in and it now reads misfire on cylinder 3, not cylinder 7. I swapped coils between 1 and 3, with no change. Misfire still on cylinder 3. Next, I unplugged injectors on that bay, 1,5, and 7 all made the engine idle worse. Unplugging cylinder 3 did not appear to worsen the trucks idle.

I cleared the codes and started the truck up. I waited for the check light to come back on, and when it did the fuel pressure rose by a lot.
F864CEB1-7BD8-47AE-AC1D-9F8B5599FAFD.jpeg


Any tips on what to do next? It seems like it’s time to take it to a shop
 
#43
Take and have the truck running and spray brake cleaner lightly around the intake gaskets to see if you have. Afresh air leak. Then if no, swap the o2's from side to side and see if it changes .
 
#45
Did you take the spark plug put yourself? If so and you still have it check for oil coking and oil residue in the plug, I bet your problem is associated with the afm. The rings may be seized or you have cam/lifter failer.
 
#47
I've gone the full AFM (Active Fuel Management) delete route on several trucks after valve lifter failures. This includes replacing the cam and all lifters, plus replacing the solenoid plate with a blank one. Also have to get the computer re-programmed to ignore the AFM system so that your check engine light won't be on all the time. The reprogramming is part of the price of this delete kit.
www.ebay.com

2007 - 2010 CHEVROLET GMC 6.0L TRUCK SUV CUSTOMIZABLE AFM DOD DELETE KIT | eBay

Find many great new & used options and get the best deals for 2007 - 2010 CHEVROLET GMC 6.0L TRUCK SUV CUSTOMIZABLE AFM DOD DELETE KIT at the best online prices at eBay! Free shipping for many products!
www.ebay.com

This type of repair is necessary if you wait until the trouble-prone system fails. If you go ahead and get the computer programmed to ignore the AFM BEFORE the POS lifters fail, then the probability of failure is much lower. It's the constant turning on/off of the oil supply to the special-made lifters that leads to their demise. Basically a really good engine design ruined by over-engineering. This system became pretty much standard in the 2007 model year.

Here's a service to reprogram the computer:
www.ebay.com

07 up Chevy GMC DOD AFM DELETE TUNING 5.3L 6.0L 6.2L DISPLACEMENT ON DEMAND | eBay

This is the ecu side of the full dod afm delete, if you have other related problems then they. internal engine work you also need to have this programming work done on the ecu. 08-10PONTIAC G8 6.0L, 6.2L.
www.ebay.com

And here's a device you plug in the diagnostic port and leave it plugged in. It will turn AFM off as long as it's plugged in and newer versions will also turn off the even more stupid program that kills your vehicle when your sitting at a stop sign and then re-starts it when your ready to go again. :
www.ebay.com

RANGE TECHNOLOGY ACTIVE FUEL MANAGEMENT AFM DISABLER FOR GM VEHICLES RA003 GREEN | eBay

Find many great new & used options and get the best deals for RANGE TECHNOLOGY ACTIVE FUEL MANAGEMENT AFM DISABLER FOR GM VEHICLES RA003 GREEN at the best online prices at eBay! Free shipping for many products!
www.ebay.com
 
#48
mtrmn said:
I've gone the full AFM (Active Fuel Management) delete route on several trucks after valve lifter failures. This includes replacing the cam and all lifters, plus replacing the solenoid plate with a blank one. Also have to get the computer re-programmed to ignore the AFM system so that your check engine light won't be on all the time. The reprogramming is part of the price of this delete kit.
www.ebay.com

2007 - 2010 CHEVROLET GMC 6.0L TRUCK SUV CUSTOMIZABLE AFM DOD DELETE KIT | eBay

Find many great new & used options and get the best deals for 2007 - 2010 CHEVROLET GMC 6.0L TRUCK SUV CUSTOMIZABLE AFM DOD DELETE KIT at the best online prices at eBay! Free shipping for many products!
www.ebay.com

This type of repair is necessary if you wait until the trouble-prone system fails. If you go ahead and get the computer programmed to ignore the AFM BEFORE the POS lifters fail, then the probability of failure is much lower. It's the constant turning on/off of the oil supply to the special-made lifters that leads to their demise. Basically a really good engine design ruined by over-engineering. This system became pretty much standard in the 2007 model year.

Here's a service to reprogram the computer:
www.ebay.com

07 up Chevy GMC DOD AFM DELETE TUNING 5.3L 6.0L 6.2L DISPLACEMENT ON DEMAND | eBay

This is the ecu side of the full dod afm delete, if you have other related problems then they. internal engine work you also need to have this programming work done on the ecu. 08-10PONTIAC G8 6.0L, 6.2L.
www.ebay.com

And here's a device you plug in the diagnostic port and leave it plugged in. It will turn AFM off as long as it's plugged in and newer versions will also turn off the even more stupid program that kills your vehicle when your sitting at a stop sign and then re-starts it when your ready to go again. :
www.ebay.com

RANGE TECHNOLOGY ACTIVE FUEL MANAGEMENT AFM DISABLER FOR GM VEHICLES RA003 GREEN | eBay

Find many great new & used options and get the best deals for RANGE TECHNOLOGY ACTIVE FUEL MANAGEMENT AFM DISABLER FOR GM VEHICLES RA003 GREEN at the best online prices at eBay! Free shipping for many products!
www.ebay.com
Click to expand...
I bought a 2012 silverado 5.3 85,000 miles about 8 months ago, I did tons of research so I was prepared for the common issues. As soon as I got the truck I changed the oil and loaded the family up and took a 2000 mile trip up to Memphis then to Gatlinburg then back to north Florida, in that 2000 mile trip I noticed 1-1.5 quarts gone. I changed the plugs just to be sure of the condition, 2 plugs out of the 4 afm cylinders had oil on them. I next installed a morroso catch can then about a week or so later I overnighted the ecm to lt1swap.com and let him disable the afm cost $100 all in for the ecm work. After running for 3000 or so miles I've noticed no appreciable oil loss truck runs great. Do your research and you"ll be fine.
 
#50
tomcatmv said:
Does the 2013 have similar issues?
Click to expand...
It has the exact same system. If it's a 5.3 then it most likely will have issues. They ran a couple of fixes in 2011 but they still have issues. I would try and buy one with less than 120000 miles on it then complete the preventative maintenance items mentioned above.
 
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