Possible afm lifter failure

[Jjohn1987]

Hey all,

New guy at the wheel so bare with me, got an 07 new body style LTZ w/ VortecMAX and absolutely love it over the past truck I had. But last weekend it developed a dead misfire on cyl. #6. Did the usual plugs, wires, swapped coils around and was trying to get a bad coil diagnosis. All coils were good, so I kinda got thrown for a loop. Figured I would try ohm testing the injector and come up with some rough ideas if it were fuel or not, and that proved negative as well. Put compression gauge on and it has great compression. So lost, I do what any person would, hopped on the ole' inter web to see if there is anyone else saying the same things and boy did I get a surprise. AFM engines eating lifters and having lifter failures. So my figuring is that the lifters that are giving (or are going to be giving) me issues are probably the the AFM cylinders, so my question is can I just change these lifters or should I do them all? This is my slow time of year income wise so I kinda have to watch what I do but I also need my truck to be reliable as well. Any suggestions or helpful comments would be greatly appreciated guys.

 

Thanks in advance...

[SILVERADOSC540]

Welcome VMax. I had an '07 VMax and loved it. Have you had it scanned or had codes pop up? I would certainly have the dealership look at it, they probably won't charge to scan codes or give you their two cents worth if you have one you trust. Once fixed either a handheld tuner like superchips or a custom tune from BlackBear(site sponsor and better option) can disable afm and also bring that engine to life. All I had was a handheld and it really woke up my '07, and BlackBear Performance is the best in the business when it comes to LS motor tunes. Goodluck with the diagnosis.

[Jjohn1987]

 

Welcome VMax. I had an '07 VMax and loved it. Have you had it scanned or had codes pop up? I would certainly have the dealership look at it, they probably won't charge to scan codes or give you their two cents worth if you have one you trust. Once fixed either a handheld tuner like superchips or a custom tune from BlackBear(site sponsor and better option) can disable afm and also bring that engine to life. All I had was a handheld and it really woke up my '07, and BlackBear Performance is the best in the business when it comes to LS motor tunes. Goodluck with the diagnosis.

Thanks I've pretty well decided it's the lifters. I've done some research and found that tsb. How hard is it to do that deactivation from everything I was told it would require a new PCM

[hzhardy]

There is also an issue with rust building up fron the steel fuel lines on the injector screen causeing a stoppage. This will not show up on a ohm test.

[RyanbabZ71]

Turning off AFm does not require a new PCM. Its an ECM flash basically or range make a product you plug into the ODBII port.

[Badass69]

Dump your oil and check it for metal both visually and via analysis. If a lifter piled up it took the cam lobe with it........ thus every bearing in the bottom end is garbage and it's bye bye engine. I hope this isn't the case for you.

 

Change all 16 lifters out if you go this route and my personal opinion is do not use GM LS7 lifters. Get Brian Tooley ones....... because I don't like Comp either lol. You need the valley cover off of an non afm engine as well..... like a 4.8 or a 6.2. It's a snowball effect though as you may as well do a cam swap while you are in there........ and so on and so on.

[2017SierraSLT]

Have you pulled a valve cover to verify that the rocker arms are moving up and down in relation to the others on cylinder 6?

[Jjohn1987]

Have you pulled a valve cover to verify that the rocker arms are moving up and down in relation to the others on cylinder 6?

That I have done and all seem to be moving as should.

[2017SierraSLT]

I would think that if you have proper compression and valve timing at cylinder 6, all that is lacking is fuel and spark. Swap fuel injectors and see if the problem changes. I have heard that carbon coked intake valves will cause a dead cylinder. The carbon acts as a fuel sponge, not allowing enough fuel into the chamber to fire.

[hzhardy]

Govtech posted the following in response to a similat issue I am having with my escalade. Befire you go off poping you heads off check this.

 

Subject: Fuel Injector Replacement Information - Inspect Fuel

Injector Inlet Filter Screen for Rust

Models: 2005-2007 Buick Rainier 2004-2007 Cadillac Escalade, Escalade ESV, Escalade

EXT 2004-2007 Chevrolet Express, Silverado, Suburban,

Tahoe 2004-2007 Chevrolet Trailblazer 2004-2007 GMC Envoy, Envoy XUV 2004-2007 GMC Savana, Sierra, Sierra Denali 2004-2007 GMC Yukon, Yukon XL and Yukon Denali XL 2004-2007 HUMMER H2 2005-2007 Saab 97x with a V8 Engine (RPOs L33, LH6, L59, LM7, LQ4, LQ9, or LR4)

 

This PI was superseded to update models and condense the

recommendations. Please discard PIP3280C.

 

 

 

The following diagnosis might be helpful if the vehicle

exhibits the symptom(s) described in this PI.

 

 

Condition/Concern:

 

Some customers may complaint of a SES light, engine misfire,

or other engine performance concerns. In some instances, their

concern may be the result of a plugged fuel injector inlet filter

screen, which may not be repaired by cleaning the fuel injectors as

outlined in 03-06-04-030.

 

 

In a returnless fuel system, all fuel leaving the tank flows

through the fuel injectors because there is not a return line for

fuel to return to the fuel tank from the engine. As a result, any

contamination (including rust) that forms in the fuel line will

find its way to the fuel injectors. The fuel injector inlet has a

filter screen to filter out small contaminants, such as rust. If

enough debris accumulates on the fuel injector inlet filter screen,

it will start to restrict fuel flow.

 

 

Recommendation/Instructions:

 

If the latest version of 03-06-04-030 leads to fuel injector

replacement, inspect the fuel injector inlet filter screen for rust

contamination. If rust contamination is present, replace the

affected fuel injector. Replacement of all steel fuel lines is also

recommended whenever rust is observed in an injector because there

is a chance that rust remains in the steel fuel lines.

 

 

Also inspect for rust in the fuel tank, which indicates that

water may be present. If present, it could affect uncoated portions

of the fuel pump and filter assembly and the fuel lines, and could

lead to a re-occurrence. If rust is observed in the fuel tank,

follow the Fuel System Cleaning Procedure in SI to clean the inside

of the fuel tank and refill with clean fuel. Also inspect the

in-tank fuel pump module and filter assembly, and replace as

necessary.

 

 

Using GM Fuel System Treatment PLUS (at oil change intervals)

can protect against the affects of water and certain contaminants

that may be present in some poor quality fuels.

 

 

Please follow this diagnostic or repair process thoroughly

and complete each step. If the condition exhibited is resolved

without completing every step, the remaining steps do not need to

be performed.

[Jjohn1987]

Well here's what I came up with, number 6 intake lifter was locked up in the compressed position and the reason the fuel was getting in there and making that plug wet, I assume was the suction from the intake stroke was strong enough to draft that intake valve out and was letting the fuel that fired out before down in with not enough air to "bang it". I will be able to post a pic or two tomorrow but have to be at work soon. Just excited to have my truck back finally!!

[rgilday]

Hey all,

New guy at the wheel so bare with me, got an 07 new body style LTZ w/ VortecMAX and absolutely love it over the past truck I had. But last weekend it developed a dead misfire on cyl. #6. Did the usual plugs, wires, swapped coils around and was trying to get a bad coil diagnosis. All coils were good, so I kinda got thrown for a loop. Figured I would try ohm testing the injector and come up with some rough ideas if it were fuel or not, and that proved negative as well. Put compression gauge on and it has great compression. So lost, I do what any person would, hopped on the ole' inter web to see if there is anyone else saying the same things and boy did I get a surprise. AFM engines eating lifters and having lifter failures. So my figuring is that the lifters that are giving (or are going to be giving) me issues are probably the the AFM cylinders, so my question is can I just change these lifters or should I do them all? This is my slow time of year income wise so I kinda have to watch what I do but I also need my truck to be reliable as well. Any suggestions or helpful comments would be greatly appreciated guys.

 

Thanks in advance...

i have a 2007 Silverado new body style, I have experienced multiple afm lifter failure. first the left bank I had a lifter go bad, locked up, not working, whatever goes bad in them. I, like a dummy, only replaced the bad one. I drove it for approximately 5000 miles after replacing it, and then the right side bank had yet another one go out. i replaced all four afm lifters on that side. approximately 8000 miles later I had one of the afm lifters that I didn't replace on the left bank go bad. this is not the easiest fix and I think gm needs to recall this particular problem in all years its effected, but they havn't.the dealership wanted in excess of $2000 to fix.... they have recalled some years so if your having this problem take your vin number to a dealership and they will be able to tell you if there is a recall on you truck. abd yes I am going to dig back into this engine and replace the remaining three lifters I so ignorantly ignored when I had the intake, head, exhaust manifold off the first time... so in doing this job yourself it will require new intake, head, exhaust gaskets. new head bolts. I did not have the head re surfaced but I would recommend it. it seems that only the afm lifters are faulty from the research ive done so I have no intentions in replacing all lifters (non afm lifters) but use your own judgment when doing the job yourself. hope this helps symptoms: running rough, check engine blinking, loud ticking noise.