2013 PPV Slight Idle Shake Unknown Cause

[1BADI5]

Well there are a number of things that come to mind here and some are simple things you can do as an owner.

1) we know the AFM is garbage and prone to lifter issues; I put 8 oz of seafoam in the oil for about 250 miles before my oil change to clean the junk out. Those small oil passages on are the issue if the vehicle did not have regular oil changes. I have seen this free up a bad lifter ( its cheap and worth a shot)

2) Motor mount(s) replacement is a common problem with the GMT900s, verify there the mounts are solid, if cracked or have excessive play; replace them(easy job) (mine were replaced at 65K)
3) Transmission mount (see #2)
4) Verify your fuel pressure at the rail, if the pressure is good, you might have a gummed up injector(s)

As a part time tech this is where I would start.

 

[CrashTestDummy]

All thanks for the input and I think I’ll invest in a tech 2 and run some tests and watch the read outs.

I do understand the service advisors position but it’s frustrating when I’m about to put down $100 to schedule an appointment and not be able to feel confident in the dealer and it’s technicians. So I’ll try again at another Chevy dealer and maybe get in sooner than 2 weeks.

You don't need a Tech2. The scanning can be successfully-completed by yourself so you get the current, valid, codes to work with.

I've used an ELM327 Bluetooth OBDII module with their ELM327Checker app on our '10 PPV and '12 9C1. I have the apps installed on our Galaxy Tab 4 tablet, but both have iDevice apps. I think the module was less than $100, and has been very useful.

When it came time to read chassis codes, I had to step up to the Bluedriver OBDII Bluetooth scan tool module and their app. The app, as usual, was free, and I think I paid about $100 for the scan tool. Both have paid for themselves if for nothing more than not having to hassle with the dealer for codes the parts house couldn't find.

Invest in one of these. I'd go with the Bluedriver, because it will scan, and clear, traction control and ABS system errors.

The apps for both will even post links you can follow for more info on each code posted.

I even know of a guy on another forum who is trying to sell his ELM327 for the price of shipping:

http://www.newcaprice.com/forum/viewtopic.php?f=32&t=3349

Do it!

 

[justme]

Please keep me posted on the results of your findings.

sorry for the delay, but my scanning method is not giving any codes. I am blaming the scan tool at the moment, but it may be the range technology device.

I need to run it without the range device for a bit and see if that yields the misfire codes I am expecting.

 

[balln2k11]

If you have the DIC buttons in your Tahoe (I would make the cheap investment if you don’t) , switch the instrument gauge to where you see the V8 or V4 mode. Drive around and see if the shake happened the same time it switches from V8 to V4 .

I did the AFM/DOD delete as I was having a similar problem after changing motor mounts, trans mounts, spark plugs (#8 plug is horrible), and bunch of other stuff and still had the same problem. After the AFM/DOD delete using my DiabloSport tuner... no more shakes.

 

[foeteef]

Thanks will check that out, yes been thinking of afm delete... does it leave check engine light on?? Not a dealbreaker but just wondering

 

[1BADI5]

Thanks will check that out, yes been thinking of afm delete... does it leave check engine light on?? Not a dealbreaker but just wondering

Well if you do a full blown AFM delete, you will need a tuner to go in and turn it off. I know with HPTuners its a super simple function to perform, but keep in mind it will still cost you $250-500 for the tuning. (Note: HPTuners $200 of that cost is just for the credits to access the VIN for tuning)

 

[RichardCranium]

P015B bank one sensor o2
P219A fuel bank 1 imbalance
P219B fuel bank 2 imbalance

Those last two are fuel trim codes, lean or rich. That certainly doesn't narrow anything down for you, but since its on both banks of the engine its likely a central source. IMO you are chasing your tail looking at oxygen sensors, I'd be looking at the MAF to see if it has anything stuck to it. Does your truck have CAI or anything? I'd also look for simple intake-side leaks, especially between the MAF and throttle body (intake boot, clamps, etc).

Well if you do a full blown AFM delete, you will need a tuner to go in and turn it off. I know with HPTuners its a super simple function to perform, but keep in mind it will still cost you $250-500 for the tuning. (Note: HPTuners $200 of that cost is just for the credits to access the VIN for tuning)

$100 to unlock the VIN.

 

[foeteef]

I'm going to run my codes tomorrow and post. No check engine light, but I know it can still ha have stored codes.

 

[1BADI5]

$100 to unlock the VIN.

Yes, Sir.......you're correct

 

[foeteef]

Well sorry for the delay in posting. But ran codes several times. None found. Check engine and transmission codes. Nothing . Used two different good scanners. OTC Genisys touch and Autel maxsys 808. Again mines sound like a light exhaust leak on right/passenger side. Have examined all over manifold and where manifold meets pipe.
But I dont think it would be that because noise and sluggish/hesitation, almost dead spot, is same time frame with rpm. Thinking of buying those diablo delete. I know its not a full delete but to see if noise/hesitation stops I'll know it's with afm or lifter tick issue. ???

 

[Doubeleive]

Well sorry for the delay in posting. But ran codes several times. None found. Check engine and transmission codes. Nothing . Used two different good scanners. OTC Genisys touch and Autel maxsys 808. Again mines sound like a light exhaust leak on right/passenger side. Have examined all over manifold and where manifold meets pipe.
But I dont think it would be that because noise and sluggish/hesitation, almost dead spot, is same time frame with rpm. Thinking of buying those diablo delete. I know its not a full delete but to see if noise/hesitation stops I'll know it's with afm or lifter tick issue. ???

have you taken the valve covers off and checked for a broken valve spring?
as for people having to wait a week or two to get into the dealer that's crazy, I can go the dealer here at 10am and have most things done by the end of the day, it has to be something pretty serious to keep it even more than 24 hours and they are a busy dealership.

 

[1BADI5]

With a broken valve spring you would normally get/have a misfire and with a PO300(general misfire) or say PO302 if it was cylinder 2

 

[Doubeleive]

With a broken valve spring you would normally get/have a misfire and with a PO300(general misfire) or say PO302 if it was cylinder 2

ya I figured but thought it could be a possibility, not sure if that would always throw code or not.

 

[foeteef]

Haven't did an inspection for broken spring. Would think it would cause an issue further through range of rpm/throttle.

 

[1BADI5]

So I did some digging into this.

I knew there was no problem with the motor, motor mounts or transmission mount.

So the OEM tuning on these trucks it odd at best. GM has the idle set around 550 rpm. I have spoken with a few local tuners and all them said the same thing; tune it. Moving the idle from stock to some where in between 600-700 rpm is the sweet spot and the idle annoyance with disappear.

For proof of concept, once the truck is at operating temperature.....your in park and the shaking is present. Shift it in to neutral, mine idles nice and smooth at 600 rpm and the shaking shit is gone.

Reflash and fixed. You might even be able to get the dealer to reflash for the idle; I have not looked to see if there was a TSB or VCN for it yet.

 

[GCATX]

I did this exact thing last week. I found an old diablo sport I had thrown in my desk drawer years ago. Turned of the DOD and bumped the idle 100, left everything else stock tune. Idle feels about 75% better. I still want to check the driver motor mount, but honestly, it's not that bad anymore.

My wife's current escalade needed new driver side motor mount at 38k miles, it was shaking at idle and had the clunk when on/off the gas. I remember we had to replace the same mount on her 08 escalade at 90k, we bought it used so it may have been done once already.

 

[1BADI5]

Thanks for your feedback

 

[State_Blue_Man]

All,
Its has been some time but I have an update. I found the driver side cat was partially plugged and surface was starting to melt. I think the was due to the 9,900-ish idle hours and lack of proper maintenance. I replaced the Y pipe assembly and resolved all of the other codes besides a P219a. The performance and fuel economy came back up but not where I was happy enough. I replaced the plugs and wires & this improved the idle condition further. The V4 plugs were bad to say the least. Come to find out i pulled the trucks service history and found out no one replaced the plugs and wires so it was long over due anyway. Next step is to test the fuel system to see if i have a bad injector or weak fuel pump.

I did have a bad trans mount and going to put on in the next few days. i found this out when i pulled the cross member to get the exhaust out.

The motor mounts are in good shape surprisingly.

Keep in mind the truck has no injector, knock, or evap faults still.

I'll keep you posted on my findings. I'm just crossing my fingers that its not the AFM/DOD starting to fail.

 

[OR VietVet]

Besides the age anyway of the cats, they were likely effected by the old plugs and wires and therefore unburned fuel got in the cats. That will damage them. The bank #1 imbalance code, P219A, could be something as simple as the injectors needing cleaned. That is also the same side as the bad cat you found. A weak fuel pump would effect both banks but it is a great idea to check the fuel pressure anyway. What brand of fuel do you use and what grade? The mid and premium grades have additives in them that help keep fuel systems/injectors clean. At this point I would use something like Chevron Techron in a tank or two and see what happens. I would also clean or replace the MAF and clean the throttle body. Check the air filter and replace as needed.

 

[State_Blue_Man]

Besides the age anyway of the cats, they were likely effected by the old plugs and wires and therefore unburned fuel got in the cats. That will damage them. The bank #1 imbalance code, P219A, could be something as simple as the injectors needing cleaned. That is also the same side as the bad cat you found. A weak fuel pump would effect both banks but it is a great idea to check the fuel pressure anyway. What brand of fuel do you use and what grade? The mid and premium grades have additives in them that help keep fuel systems/injectors clean. At this point I would use something like Chevron Techron in a tank or two and see what happens. I would also clean or replace the MAF and clean the throttle body. Check the air filter and replace as needed.

Yes, I believe you are correct in that assumption this is leading me to a fuel injector / system problem when going into V4 mode. So this may narrow down the two injectors to pull first. (I'm going to pull them all while I'm in there and clean if i can)

Any recommendations on OEM replacement injectors? I see many types out there for really cheap and super expensive.

I'm currently running 92 (from costco) in the tank to help clean out the system with injector fuel system cleaner from seafoam. The idle condition improved about 1/2 way thought the tank. I still and 1/2 way to go till empty. I'm going to clean the top end with some MAF cleaner and TB cleaner. Then go through a visual inspection again encase i missed something like a vacuum or exhaust leak.

I'll keep you all posted and send some Pics.