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Stuntmanmike77

Original poster
Member
May 6, 2018
137
Sanford, ME
Hey everyone. Not sure if it goes here but, besides removing or replacing the fuel injectors I decided to go with a can of seafoam before I fill my tank but, my wife accidentally got the spray seafoam with the intake hose straw. Would this work well cleaning some junk out of there? I know it wont go through the injectors but just wondering if this is safe and effective on these 4.2 engines?
 

mrrsm

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Stuntmanmike77

Original poster
Member
May 6, 2018
137
Sanford, ME
Is this stuff effective? Got some slight hesitation and a new fuel pump so I thought this would be a good option for now instead of putting chemicals through my new pump? Idk I've never used it this way before.
 

hockeyman

Member
Aug 26, 2012
726
I've been one to always use a fuel injector cleaner when doing an oil change, then filling the tank shortly afterwards to help move any residue through it. That said, I have used seafoam on many of occasions (including in my previously owned 2003 Envoy with a 4.2) and did not have any issues afterwards. Did it work? I don't know because there were no hesitation problems beforehand. It was sorta a preventive maintenance thing.

In many of my previously owned vehicles, I've applied seafoam in both the intake vacuum tube and the fuel tank. The intake vacuum tube is much more fun due to the huge plume of smoke it creates shortly after it's used, but I have to admit that I never removed any of my intake manifolds before/after to inspect them to see if it actually did anything or not. It just made me "think" that it did.

My advice is to first identify your hesitation, then go from there. You can dump all kinds of money and products into the fuel tank and vacuum tube, trying to solve the problem, then come back and say that seafoam doesn't do crap....only to find that your hesitation was being caused by (something like) a burnt spark plug wire.
 
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mrrsm

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I'm not sure whether the topic of "How to Diagnose EFI Problems" has been covered yet... but finding something definitive by using an OBD2 Diagnostic Scanner that can give you some Live, Comparative Data to really confirm that the problem does occur because of poor EFI performance is good beginning. This video will give you a General Idea on how to perform this same test with Common OBD2 Equipment on your SUV, because guessing that to be the case could become OBPITA (One Big Pain In The A**) and STILL not solve the problem:


Your instinct to avoid punishing your New Fuel Pump does you credit. Chemicals created to dissolve thickened, Gasoline Gum and Carbon Deposits that dwell in combustion chambers are meant to be used in as close a concentration as possible. Chemicals like ACDelco TEC (Top Engine Cleaner AKA X66P), Berryman's B12 and the BG-44 type products all work equally well.

However, if dumped directly into the Fuel Tank, they can also soften and dissolve the Rubber Seals inside of the Electric Fuel Pump as well. There are quite a few Threads that cover De-Carboninizing Stuck Compression Rings, Carbon impacted Valve Seats and thickly Carboned Up Piston Heads to restore normal compression and fuel efficiency using the ACDelco TEC via removing the Spark Plugs and injecting the stuff directly into each Cylinder for an extended soak. This must of course be followed by evacuating the Black Carbon Mung that will pool and puddle inside ...before re-installing the Plugs, lest the Goo cause the Rotating Assembly to Hydro-Lock and damage the Engine.

These Harsh Chemical Products should NOT be introduced through the Air Stream as the EFI System is discreetly isolated within its own separate Fuel Line to EFI to Intake Manifold delivery Ports and the stuff will never get to the 'innards' of each Fuel Injector to do its job.

Ordinarily, GM Techs use the GM Tech 2 Hand Held Scanner to perform a "Cylinder Power Balance Test" to determine Cylinder By Cylinder which one is suffering from any performance loss:


The other more laborious method employs the use of an Analog Fuel Pressure Test Gauge and by cycling each EFI... again... Using the Tech 2 to isolate one EFI at a time while the others get disabled... and observing the amount of the Drop in Fuel Pressure individually for each one. In this manner, isolated, misbehaving Fuel Injectors can be identified.

It is too bad that the very involved R&R of the Intake Manifold must be done first before removing the Fuel Rail and Fuel Injectors and either replacing one...or all of them at once if you prefer.... but that is what will be called for if you finally decide to get a Re-manned Set of (6) Injectors and wind up replacing them all as a long term solution. Your profile does not include the Year of Manufacture for your SUV... but armed with that data and search on Amazon will reveal some Vendors who offer these EFIs in Re-Man Sets for around $100 to $150.
 
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Stuntmanmike77

Original poster
Member
May 6, 2018
137
Sanford, ME
I might look into r&r the injectors cause my valve cover is starting to seep and gotta remove the intake anyway. Love all the great info, very helpful. And I'm sure there is a debate about this but, changing my vvt sensor cause the connection has oil in it and it's original. Wanted to go with a good high mileage synthetic. Been using the walmart supertech brand but wanted to try something like castrol edge or valvoline synthetic. What seems to be popular for these engines?
 
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Sparky

Member
Dec 4, 2011
12,927
Anything decent is fine. Really. I ran mobil 1 the whole time in mine but that was just me. Had good results so I stuck with it.
 
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mrrsm

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I'm a 'Dyed in the Wool' Mobil1 5W-30 Fully Synthetic Oil Fan ...and the same goes for using either K&N or Mobil1 Oil Filters as well. But many other well-informed GMTN Members like Amsoil, Royal Purple or ANY other Fully Synthetic Motor Oils, too. If you live in very cold climes... switching over to Mobil1 0W-30 will ensure good Low Temperature Lubrication during Start Ups in particular will improve the performance and life of these engines during very frigid times.

The most Important Thing concerning all of these Motor Oils has less to do about what you choose...and more to do with how often you choose to Change the Oil and Oil Filters. High Mileage Engines have problems of excessive Blow By from Incomplete Combustion By-Products passing the Piston Rings and contaminating the Motor Oil much sooner than the popular fallacy that allowing your engine to go as long as 5,000 Miles instead of using 3,000 Miles as the Bench Mark.

Owners of such vehicles will wind up with their Fully Synthetic Motor Oil getting 'watered down' by a Cocktail of Unburned and Pure Gasoline mixing with the Motor Oil down inside of the Crankcase and destroying its lubricity right along with all of the advertised benefits that Synthetic Motor Oils get touted for. In some cases ...the Gas Gum can clog the Oil Pick Up Tube enough to completely Block any Oil from entering the engine at higher RPM. Cylinder Wear and Badly Worn Babbitt Bearings due to Oil Starvation Herald the Death Knell of all engines suffering from these conditions.

And when it comes to the VVT controlled Engines in the GM Atlas Family... Dirty Motor Oil invariably causes performance problems with Clogged (or completely lost) CPAS Screens and the infamous P0016 and P0017 Codes getting thrown along with the rough idle and poor performance. Clean, Filtered Motor Oil is the Life's Blood of this and any other Engine and demands that Oil Changes should be done regularly and at intervals that side-step all of the fallacies surrounding the idea that, "Hell...You could go 15,000 on a Full Synthetic, Ya Know...?" Yeah... Right. That's it... He's being 'frugal'...

The GM 4.2L Engine cringes to hear such nonsense because in the first instance... it cannot perform well if the Oil Level never gets checked often enough to keep the Volume of Oil as close to a full level of 7 Quarts as possible over time...and even so... in the second instance... it must have that expensive Motor Oil and Filter changed out, too ...right on schedule. This Engine runs on Oil Pressure as Low as 12 PSI at a low idle and reaches a high pressure level at around 65 PSI above 3,000 RPM... so that means that the Crankshaft Mounted Gerotor Oil Pump moves over 11 Gallons of Oil Per Minute at that RPM. Ergo... Treat your Engine to these wonderful, regular "infusions of Liquid Gold" ...and it will simply run better for a much longer time. :>)
 
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Sparky

Member
Dec 4, 2011
12,927
I do not believe these engines are near so sensitive at all given my experience and others. I ran mobil 1 yes, but I changed it when the light said to which was averaged 10k miles or so. One time it was as much as 14k. Of course, type of driving (city vs highway, short vs long drive cycles) makes a big difference. Result? At 215k miles it would be at or still a bit above the add 1 qt line on the dipstick after 10k miles.

I would not go 10k on cheap noname oil, but decent stuff I have no qualms about it. If you want to change at 5k then fine, but with good oil and filter it is not necessary.

I now have a 5.3L which not only has 2 cyl more but 1 qt less, so it needs changed more often. I still get around 7k or so. Needs the oil topped up halfway thru but i have several oil leaks that help contribute to that. It has 205k on it and it runs strong still.
 

Mooseman

Moderator
Dec 4, 2011
25,257
Ottawa, ON
And the quality of oil has gone up so much that OEM's are now specifying thinner and thinner oil. At my former work, the 2015 Tahoe specifies 0w20 Dexos whereas the vehicle it replaced, a 2011, was 5w30 synth, both with the 5.3.

If you're really interested, there is this post on the 4 stroke snowmobile forum I frequent, where oil is a very hotly debated topic, that has a ranking for shear strength of each brand. Some surprises in there.

 
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Sparky

Member
Dec 4, 2011
12,927
Well the 2015 5.3L is different than the 2011 5.3L, so the design spec for the oil is also different.
 

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