I put a gallon of MMO in my gas tank...

Originally Posted by Vladiator
Originally Posted by dave123
You can't fix stupid.

It was an experiment: my time, my money, my consequences. Absolutely no reason to start the name calling, bud.

The point of any experiment is to find PROs/CONs of an idea. In this case CONs outweighed the PROs, so I am sharing my experience in case someone out there decides to do the same and hopefully stumbles across this thread.


I appreciate you doing this and coming on here letting us know. Knowing that there would be the know it alls piping in made it even more worthwhile to see their panties in a wad!
 
A whole gallon, yikes.
crazy2.gif
Most I've used is ~ 1 quart in a full tank of fuel that is 20 gallons.
 
Holy moses that is a lot of MMO! I personally use it in the F-150, which has smoothed out the idle quite a bit. But that sounds crazy. However, I appreciate your willingness to experiment
smile.gif
 
Originally Posted by Vladiator


Moral of the story? Don't put a gallon of MMO in your gas tank, .


I applaud your effort. While it may seem self evident to most of us that MMO in large concentrations is unhelpful, just what exactly happens is another matter.

I wonder if it had any cleaning effect?
 
I appreciate you sharing. All we've had are some pretty sweet under-the-valve-cover pics to keep us entertained recently.

Originally Posted by dave123
You can't fix stupid.


Now, that's just not necessary.
 
Originally Posted by Donald
Originally Posted by Vladiator
Just for S&G I put a gallon of Marvel Mystery Oil in my ~30 gallon gas tank of 1995 Chevy Tahoe before fill up.

It was going great and smooth, until 40 miles into the gas tank... The misfires started... Multiple misfires, and OBD1 only gave code 32 (EGR code). Over the last couple tanks misfires kept getting worse, even the slightest incline caused a couple downshifts to help the ol´ 5.7L pull the heavy Tahoe.

Today took out the OEM AC Delco plugs that I installed about 10k miles ago and found them to be very wet, most likely with MMO, as it is an oil and doesn't burn off as fast as gas. Replaced the copper AC Delco plugs with NGK Platinums... All I can say is I should've got these plugs to begin with, because the engine is MUCH smoother now. Misfires obviously gone. Engine is smoother than it was before the misfires, and smoother than it was with brand new AC Delco copper plugs.

Moral of the story? Don't put a gallon of MMO in your gas tank, unless it is a 100 gallon fuel tank. 1qt is plenty for preventative maintenance. I just wanted to see what severe overdose will do and it did exactly what I expected it to do.


Is your name Scotty Kilmer?



He stated MMO is old school and has no business in a modern gasoline engine.
 
Originally Posted by Cujet
Originally Posted by Vladiator


Moral of the story? Don't put a gallon of MMO in your gas tank, .


I applaud your effort. While it may seem self evident to most of us that MMO in large concentrations is unhelpful, just what exactly happens is another matter.

I wonder if it had any cleaning effect?



The last part is the real question.
 
I hope it did some cleaning, even though there isn't much to do - just two beefy fuel injectors, one for each head. And of course the intake valves. Good old GM Throttle Body Injection. I doubt I'll ever repeat this test though... It was miserable driving a V8 that is misfiring and makes 63hp at wide open throttle. Glad to have all 190hp back now.

One thing I did notice is that the spark plugs that were farthest away from the injectors were the wet ones(1/2/7/8), and spark plugs in the middle cylinders were dry and looked decent(3/4/5/6).
[Linked Image]
 
Originally Posted by StevieC
A whole gallon, yikes.
crazy2.gif
Most I've used is ~ 1 quart in a full tank of fuel that is 20 gallons.

I did a little more than that with no noticeable negative impact. IIRC it smoothed out the idle a bit in an old beater. It would have been interesting to see borescope pictures of the piston tops after a full tank of the mix was burnt. But with misfires and fouled plugs the CC was probably taking a beating. I wonder if there was any negative long term impact on the CC?
 
Originally Posted by dave1251
Originally Posted by Donald


Is your name Scotty Kilmer?



He stated MMO is old school and has no business in a modern gasoline engine.

Thankfully my engine is faaaar from being "modern". So far actually that it can easily be converted to being carburated, like the SBC 350 from the 1960s were
 
More catalyst-safe (those things are expensive) is a PEA based cleaner, and using a double or triple dose of that wouldn't foul the plugs like all this MMO did.
MMO is known to have solvents, so it should remove some gum or varnish at least.
 
Originally Posted by nicholas
Every forum has a couple of these guys - - - - I call them internet weasels.

They would never say anything like that to your face - - - - because they know you would smash it in.

Just give the weasels their forum to feel tough.........................

Of course I'd say it to his face if it was my own son I would say boy you stupid and sit him down and ask how you get so stupid. I got no problem telling someone they that dumb this world is full of idiots.
 
Was their any indication of severe detonation? That much MMO would cause a significant decrease in octane of the resulting mix vs. pump fuel. There was an aviation accident with an ag plane where, if I remember correctly, the operator put enough MMO for the fill up into one tank which when selected, produced the expected results.
 
Originally Posted by wings&wheels
Was their any indication of severe detonation? That much MMO would cause a significant decrease in octane of the resulting mix vs. pump fuel. There was an aviation accident with an ag plane where, if I remember correctly, the operator put enough MMO for the fill up into one tank which when selected, produced the expected results.



I did not feel or hear any pinging/knocking/detonation. Just misfire after more than 5 minutes of idle, or at any load over 1700rpm.
*[Redline starts somewhere around 4500rpm, so staying below 1700rpm still produced enough torque to keep the Tahoe moving up to highway speeds.]*

The misfires under load made it feel like the engine was only running on 4 cylinders, and the fact that 4 of the spark plugs were dry-ish and other 4 were pretty wet tells me that this theory may be correct.
 
Originally Posted by slacktide_bitog
a gallon of MMO probably isn't a lot for a 30-gal gas tank, even though it is much more than you should use!

It is like putting 2 quarts, a half gallon, in a 15-gal tank, which is around the size of most cars' tanks.


Considering that the accepted ratio of MMO to gas is approximately 4oz MMO per 10 gallons of gas, for a 30 gallon tank, 12 ounces would have been the correct amount to add.. And he added more than 10 times as much.. I'd say it IS a lot for that 30-gal tank. WAY too much. I'm not at all surprised that he had so many problems. That amount of MMO was enough to treat 320 gallons!
 
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