Any Mechanics out there?

[chas0218]

15 minutes ago, Arcade Hunter said:

Keep in mind that he does not have the same engine in his 07.... great price on your motor by the way.

Yeah I was going to throw in a 6.0 and 4l80e tranny but they wanted 1k each so opted for the stock replacement. It had the water pump just minus the accessories. It took longer for me to pull my motor than it did to put the new one in because of all the rusted bolts. The "classic" 07 model is the same as my 03. If he has the earlier make then I'm guessing he had the same problem as me if the later NNBS (new new body style) then it will most likely be the afm motor. If he has the afm motor i would look into a lifter issue. I'm not sure which number cylinder it was but the afm cylinders were the culprit and was usually the intake valve lifter.

 

EDIT:I did forget to mention that the compression test will come back all good even if it is a lifter issue. The issue is the lifter becomes lazy and doesn't pump up with oil pressure and the intake valve stays shut.

Edited January 17, 2017 by chas0218

[Arcade Hunter]

29 minutes ago, chas0218 said:

EDIT:I did forget to mention that the compression test will come back all good even if it is a lifter issue. The issue is the lifter becomes lazy and doesn't pump up with oil pressure and the intake valve stays shut.

True that.  Oil has to be under pressure.  

 

[stubby68]

38 minutes ago, chas0218 said:

Yeah I was going to throw in a 6.0 and 4l80e tranny but they wanted 1k each so opted for the stock replacement. It had the water pump just minus the accessories. It took longer for me to pull my motor than it did to put the new one in because of all the rusted bolts. The "classic" 07 model is the same as my 03. If he has the earlier make then I'm guessing he had the same problem as me if the later NNBS (new new body style) then it will most likely be the afm motor. If he has the afm motor i would look into a lifter issue. I'm not sure which number cylinder it was but the afm cylinders were the culprit and was usually the intake valve lifter.

 

EDIT:I did forget to mention that the compression test will come back all good even if it is a lifter issue. The issue is the lifter becomes lazy and doesn't pump up with oil pressure and the intake valve stays shut.

The problem was number 4 and 8. The cam flattens out and does not give enough push on lifter. I wouldn't go with a 6.0 unless getting one put out after 2015. The earlier ones really lacked on power. My opinion.

[Five Seasons]

at that mileage I can't imagine there aren't other issues and problems ready to happen. might be time to call it quits. good luck. I nursed a beater truck along and did more work than I should have just to get another year out of it.

[chas0218]

14 minutes ago, Belo said:

at that mileage I can't imagine there aren't other issues and problems ready to happen. might be time to call it quits. good luck. I nursed a beater truck along and did more work than I should have just to get another year out of it.

Been in this boat for the last 3 years, and need another 5 out of my truck until we can afford a new one. I think a vehicle lift is in my future if I'm going to keep working on my vehicles. 

[Five Seasons]

there's nothing wrong with keeping a truck going with diy work. My issue was that everything I touched was rusted and broke. It made even simple jobs headaches. When I noticed the frame was rusting pretty good as well I knew it was time. Unfortunately this is an issue when you buy a used truck that the previous owner didn't wash enough in the winter.

[Jeremy K]

My 99 chevy with the 5.3 was the biggest rot box ever ! I sold it to my buddy who knew it was rotted bad ,the drive train has over 200k and still runs great. Never had many problems with that truck except the brake lines rotting out and the ABS sensor issue.

[First-light]

7 hours ago, Arcade Hunter said:

Do a compression test.  Try to rule out mechanical failure first.  If it is, you may just need to do the heads.  Your 07 has (or at least my 07 Tahoe) has cylinder deactivation, meaning four cylinders drop out when engine power is not required.  It does this by redirecting oil to certain lifters to cause the valves to stay open hence, dropping out the cylinder.  Compression test may tell you to look at this closer at this system.

Also.... You should be using an AC Delco (original equipment) oil filter as they have a modified oil bypass circuit that can handle the cylinder deactivation system.  Using any other brand could starve part of your engine of pressurized oil.  Ask me how I know!

Also, there is a second oil filter on your vehicle (if equipped with cylinder deactivation).  It is located under the passenger side valve cover.  I have not had to mess with mine yet (157,000 miles on it) but if I recall it is serviceable.

The 8-4 cylinder deactivation is acting funny. When the stabilitrack goes off I lose the 4cylider option. It stays on 8 cylinder all the time. 

[First-light]

Also have to say truck runs better after first start up when its cold. 

[NFA-ADK]

To check the cam you only have to take off the valve cover and run it.  Not sure how easy it is on this model on that side.  Simple test if the valve cover can come off with easy.  Otherwise swapping the injectors is another way of testing but an injector test is best to see if it's getting signal.  To me it sounds like you might have a bad cam because you checked most of the other things.  If fuel presser and volume is good an the injector is firing then I would think mechanical.  Usually a valve or spring issue would be associated with some noise so if that is not the case it leads back to cam or something electrical. 

I would take it to the dealer.  They are more experienced with the product and might have the answers you need.  I have seen issues like this then they replace the engine and have the exact same issue. 

Good luck First-Light, keep us posted!

[First-light]

Here is the latest update. Talked with the Chevy dealer. Service manager said it could be a cam problem but they didn't detect any noise. Stabiltrack will shut off when the truck misfires. My mechanic still wants me to run the truck with the fuel additive to clean out the carbon. Well I got in the truck this morning and the engine light was off. Ran it about 50 miles and it is still off. Going to do 1 more can of the Techtron and see what happens. Truck still has a slight rough idle but I would imagine any car with 200,000 miles on it would. 

[NFA-ADK]

If you have a lot of carbon build up it can clog the engine.  A quicker way of doing this it to remove the air intake and spray top engine cleaner into the throttle body.  It can cause misfire when doing this so sometimes it will set off a check engine light.   You have to rev the engine when spraying the cleaner to keep it running.  Usually one can will clean most things out. 

 

Good luck, hope that's all it was is carbon build up! 

(Usually I do the top engine cleaner before replacing plugs as this can foul them out.)

[First-light]

18 hours ago, NFA-ADK said:

If you have a lot of carbon build up it can clog the engine.  A quicker way of doing this it to remove the air intake and spray top engine cleaner into the throttle body.  It can cause misfire when doing this so sometimes it will set off a check engine light.   You have to rev the engine when spraying the cleaner to keep it running.  Usually one can will clean most things out. 

 

Good luck, hope that's all it was is carbon build up! 

(Usually I do the top engine cleaner before replacing plugs as this can foul them out.)

NFA, That sounds like a good idea. I also noticed the tuneup last year didn't include new wires. So the wires on the truck have 100,000 miles on them. I'll do the Top cleaner run it then change the wires and plugs. Thanks for the advice. 

FL

[Five Seasons]

My 99 chevy with the 5.3 was the biggest rot box ever ! I sold it to my buddy who knew it was rotted bad ,the drive train has over 200k and still runs great. Never had many problems with that truck except the brake lines rotting out and the ABS sensor issue.

That's funny, rear brake line was the last job I did and the abs issue drove me nuts but at least I could stop. Needing new tires for the winter was when I realized it just wasn't worth it anymore.

[Five Seasons]

Sea foam is great. Don't just do the tank, suck it up your vac line. I did this a while back on my wife's protege and the carbon that came out of the tail pipe was unreal. Smoked up the neighborhood, it was pretty cool.

[Jeremy K]

38 minutes ago, Belo said:

 

That's funny, rear brake line was the last job I did and the abs issue drove me nuts but at least I could stop. Needing new tires for the winter was when I realized it just wasn't worth it anymore.

 

I did all the brake lines at the same time before realizing you need the computer to cycle the ABS to get all the air out of the system. I decided to take a few drives around the block with the old faulty ABS sensors still in and return home to do another round of bleeding ,I think it took 3 tries.

[chas0218]

On 1/21/2017 at 1:30 PM, NFA-ADK said:

If you have a lot of carbon build up it can clog the engine.  A quicker way of doing this it to remove the air intake and spray top engine cleaner into the throttle body.  It can cause misfire when doing this so sometimes it will set off a check engine light.   You have to rev the engine when spraying the cleaner to keep it running.  Usually one can will clean most things out. 

 

Good luck, hope that's all it was is carbon build up! 

(Usually I do the top engine cleaner before replacing plugs as this can foul them out.)

Seafoam in the can works well for this, like mentioned it will usually set off the light. You can reset the light by disconnecting one of your battery terminals for 5 minutes if the CEL comes on normally it is just the service light.

My little grocery getter Pontiac Vibe AWD has 216k on it she purrs like a kitten still. When was the last time plugs were replaced? I am betting they have to be pretty rough looking if they have 100k+ on them.

I would also be running some sort of fuel system cleaner through the tank as well as doing the saw foam through the vacuum hose method or the spray into the intake. I would throw  the cleaner in at around half tank for a higher concentration to work on those deposits a little better. Look at cleaning your Mass Air Flow sensor with a can of the cleaner. These are all things that can cause the truck to run differently because they are dirty.

Edited January 23, 2017 by chas0218

[Five Seasons]

21 hours ago, Jeremy K said:

I did all the brake lines at the same time before realizing you need the computer to cycle the ABS to get all the air out of the system. I decided to take a few drives around the block with the old faulty ABS sensors still in and return home to do another round of bleeding ,I think it took 3 tries.

the abs issue I was referring to is in the sensors. they rust and start tripping out on you activating the abs when you stop at slow speeds.

[Jeremy K]

24 minutes ago, Belo said:

the abs issue I was referring to is in the sensors. they rust and start tripping out on you activating the abs when you stop at slow speeds.

Same here ,I left those in so that the abs would go off and get the air out of the abs block after doing the brake lines . Afterwards I cleaned the mounting area and put new sensors in. 

[stubby68]

23 minutes ago, Jeremy K said:

Same here ,I left those in so that the abs would go off and get the air out of the abs block after doing the brake lines . Afterwards I cleaned the mounting area and put new sensors in. 

Have been working on vehicle my whole life. Never once have I had a problem bleeding brakes. Never needed a computer or special tool. Leave breeders open until fluid runs out. Tighten bleeders ,have someone pumps brakes 3 or 4 times then hold peddle down Crack bleeder on right rear to let air out. Repeat this till you are not getting air from line. Repeat the same on left rear then do the front. Takes maybe 10 minutes total time.  Garages will tell you anything to get your money.

[RobC]

The only time I ever had problem bleeding brakes was when the brake booster on the truck went bad.

[wdswtr]

Firstlight is your vehicle maintaining coolant levels or you needing to top it off once in a while?  You could also have a head gasket leak letting coolant into #8 cylinder.  This would cause skipping and misfires in that cylinder and dependant on size of leak even a complete non detenation. Whats the plug itself look like?

[Jeremy K]

2 hours ago, stubby68 said:

Have been working on vehicle my whole life. Never once have I had a problem bleeding brakes. Never needed a computer or special tool. Leave breeders open until fluid runs out. Tighten bleeders ,have someone pumps brakes 3 or 4 times then hold peddle down Crack bleeder on right rear to let air out. Repeat this till you are not getting air from line. Repeat the same on left rear then do the front. Takes maybe 10 minutes total time.  Garages will tell you anything to get your money.

That's why I don't go to a garage ,I've never had an issue bleeding brakes either until I had all the lines off that chevy . You could do some research and you'll see that In fact you do need a tech 1 scan tool to actuate the valves in the abs to release trapped air in the block or do what I did. 

Edited January 24, 2017 by Jeremy K

[stubby68]

3 hours ago, Jeremy K said:

That's why I don't go to a garage ,I've never had an issue bleeding brakes either until I had all the lines off that chevy . You could do some research and you'll see that In fact you do need a tech 1 scan tool to actuate the valves in the abs to release trapped air in the block or do what I did. 

Just did all lines and a caliper on a 08 Chevy on Saturday. No problems. Impossible to get air in there unless paddle is depressed while lines off and system open. Pressing peddle while lines off or bleeder open will suck air in. Like I said I have been doing this all my life. Not just a back yard mechanic. If and module is replaced it will need cycling to pure air when filled with fluid. Just doing work on line or anything after it will not let air in. Unless u have no fluid in master or pump peddle and suck air in.

[NFA-ADK]

Best bet when bleeding brakes is to try and place a hose around the line and place the other end in brake fluid container, this way all the fluid does not run out, make sure the container is above the line and keep the master cylinder closed until the job is done.  This will prevent the entire line from filling w/air and make the bleeding a standard procedure instead of needing another diagnostic tool to purge the air.

ABS sometimes requires special procedure to purge all the lines.  Some even require special tools like the S10 Blazer.

 

100,000 miles on the wires, I would say that is a problem.  Bet you notice the issue more when it is wet out!  Rain makes the wires arc as water transmits electric better than air.  This can be tested by power braking the engine and looking for sparks in the dark, just make sure you block the tires and put extra strong leg on the brake to prevent vehicle from moving.  Sometimes you can hear the "Tick" of the arc and notice that is when it runs rough.  

Sounds like you are closer to a fix, good luck!