I recently went through hell with misfire smoke out the exhaust and no power. I diagnosed stiction in a 7.3 powerstroke 308,000 miles. I dumped two quarts of hot shots stiction eliminator and my problem is gone that stuff really works good. My question is can I use more readily available products for stiction. Can I safely use marvel mystery oil in the engine oil in a HEUI hpop 7.3 powerstroke or what about rislone. Stiction is caused by varnish so what other products are safe?
Bad stiction issues 7.3 powerstroke mmo?
- Thread starter don1911
- Start date
Can you explain how you diagnose stiction?
CleanSump
Site Donor 2026
This always turns into a good one. Outside of people who own HUEI injector engines everyone piles on to claim "stiction" isn't real etc. etc. HUEI hpop injectors dirty up and start sticking. The term "stiction" is commonly used to describe the dirty oil powered injector issue.
Lets please stay with can MMO keep the injectors oil side clean rather than get into the endless is stiction real debate.
Lets please stay with can MMO keep the injectors oil side clean rather than get into the endless is stiction real debate.
Smoke out the exhaust low power engine sounds rough
But that is not the true definition of the word
Are we talking about sticky nasty piston rings or sticking open/closed fuel injectors?
Stiction
Stiction is the force that needs to be overcome to enable relative motion of stationary objects in contact. Any solid objects pressing against each other will require some threshold of force parallel to the surface of contact in order to overcome static adhesion. Stiction is a threshold, not a continuous force.
Hi don, what did you do when you diagnosed the injector issue? If you hooked up a scanner (ForScan or such) and ran a buzz test that will tell you a lot. But there are many other parameters that affect this and plenty of old-ball causes.
So if the Hotshots worked, the varnish or sludge causing the faulty injection process can be prevented and cleaned up. I would use a good HDEO changed early (1 do one year ~ 3000 miles on my 7.3) and a fuel additive, no oil additive. All MMO will do is thin and dilute good engine oil. Don't forget that when these trucks were new, Ultra Low Sulfur Diesel was not a thing. So now you are combining old age, some varnish, and fuel with no lubricity. Bound for issues.
Lots of good choices for engine oil and fuel additives.
Oil: Delvac, Amsoil, Motorcraft, even good old Brotella. I have T6 in the truck right now with a Donaldson filter.
For fuel additives (don't forget to keep the fuel filter changed and bowl clean!), I like Archoil, Amsoil All-In-One, and Power Service. I'm using up a stash of Hotshots Lubricity Improver and probably won't buy it again. All-In-One does the job and keep low temp treatment year round.
So if the Hotshots worked, the varnish or sludge causing the faulty injection process can be prevented and cleaned up. I would use a good HDEO changed early (1 do one year ~ 3000 miles on my 7.3) and a fuel additive, no oil additive. All MMO will do is thin and dilute good engine oil. Don't forget that when these trucks were new, Ultra Low Sulfur Diesel was not a thing. So now you are combining old age, some varnish, and fuel with no lubricity. Bound for issues.
Lots of good choices for engine oil and fuel additives.
Oil: Delvac, Amsoil, Motorcraft, even good old Brotella. I have T6 in the truck right now with a Donaldson filter.
For fuel additives (don't forget to keep the fuel filter changed and bowl clean!), I like Archoil, Amsoil All-In-One, and Power Service. I'm using up a stash of Hotshots Lubricity Improver and probably won't buy it again. All-In-One does the job and keep low temp treatment year round.
CleanSump
Site Donor 2026
That is it! The subject is sticky, oil actuated, fuel injectors that the internals resist movement due to the lacquer and deposit buildup in the actuators. They're very dependent on being clean.
https://bostechauto.com/blog/what-i...PI4piKk36PditQjJ0gzw80TOsEYiruNX9Bsn_dzF_Jn6j
Yes you can run them safely. They will thin the oil and your wallet.
My answer to 7.3 stiction is some kind of lube in the fuel, pulling a 10K load up a long hill occasionally, and fresh15w40 every 4000ish miles whether it needs it or not. No stiction/injector issues for the 23 years 210k I have owned it.
At 300k plus miles, do those injectors owe you a thing? I would think about sending them in or getting new ones.
There are a lot of crappy injectors on the market and only a few decent ones. And the job isn't really difficult, but its time, patience and a lot of care needs to be taken. If the stock injectors are not leaking, O-rings not leaking, cups not cracked, and firing well, I'd leave them in. But like you said, there are some things that should be done to to verify the health of the injectors. The buzz test is one and is easy to do.
In the HFRR test (diesel fuel lubricity) MMO made the diesel fuel worse than diesel fuel alone.
I think Archoil and LubeGuard are the top ones as far as helping with diesel fuel lubricity.
I think Archoil and LubeGuard are the top ones as far as helping with diesel fuel lubricity.
Yeah my veterans administration disability benefits should start next month so I will have money for injectors
If there is confirmed stiction issues, it may be time to shim the injectors. Yes, it's a thing...I did it on my 2000 F250 about 12 years ago when I had 250K on my 7.3's stock injectors. Really helped with start-up, running and slightly with fuel economy. I purchased a kit off of Ebay from USA seller/supplier and was pretty simple, torquing the injector and rocker hold down bolts while in there really helped quiet down the engine as well. I now have 434K on my original stock injectors. Hope this helps
Don - will you have a shop do these or replace them yourself? For the record, I have never even cracked the valve cover off of mine, but I have replaced the turbo, up pipes, and pedestal and a host of other top end things. From my understanding, the cups and injectors are not difficult with the proper tools, but getting everything to seal correctly can be a pain. Lots of amateurs have rolled an O-ring and caused massive issues at start-up.
Research before you buy. My experience is that you can't go wrong using OEM or Riffraff parts. Everything else is suspect. BTW- Riffraff has installation guides for most of the parts they sell. Very helpful. Same goes for diesel shops. Research, research, research.
@aquartlow - did you replace the injector cups? I'm assuming you replaced all of the O-rings on each. What other work did you do? The under cover injector harnesses?
Research before you buy. My experience is that you can't go wrong using OEM or Riffraff parts. Everything else is suspect. BTW- Riffraff has installation guides for most of the parts they sell. Very helpful. Same goes for diesel shops. Research, research, research.
@aquartlow - did you replace the injector cups? I'm assuming you replaced all of the O-rings on each. What other work did you do? The under cover injector harnesses?
No sir! Shimming the injectors only involves removing the solenoids, not the entire injector, to gain access to the armature plate to both measure clearances and to modify the armature spacer plate for improved oil draining. Decent video showing basically the same procedure as the instructions included with the shimming kit.
The one thing I did to help with removal and installation process was welding the provided bits to some 1/4" drive extensions to lessen the likelihood of the bits dropping into the engine. While I was "in there", I replaced the injector/glow plug harnesses(all the glow plugs actually still tested or rather Ohm'd out as being good). FWIW, I tried Archoil and it "helped" but realizing that the costs involved for continuous Archoil applications pushed me toward the armature/poppet valve clearance issue, this kit resolved that so no more Archoil has been needed since this was done, this 434K truck is my daily driver. This shim kit will not fix injector failure issues, just issues associated with lessened armature clearances. Hope this is helpful.
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Uneducated hunch from a fellow 7.3 owner: do a run of Redline 15w40 to further help clean up the oil side of the injectors. Fuel side, a couple of treatments of PS diesel Kleen or Hot Shots diesel extreme or similar. Sounds like the stiction eliminator actually did help.
Injector guy in Ohio said 7 of my originals had very little wear on them at 380k, and the other was a POS reman that never ran or tested right, but he fixed it. They can last the usable life of the truck with proper maintenance.
Injector guy in Ohio said 7 of my originals had very little wear on them at 380k, and the other was a POS reman that never ran or tested right, but he fixed it. They can last the usable life of the truck with proper maintenance.
You could always run a lower dose of the Stiction Eliminator with each oil change.
What does this have to do with the OP's question?
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