Fuel injector cleaners tests

These tests were done by me to help determine the best products:

Background about tests:

As a worst case sample of material which might be found in gasoline I used ordinary tar. The brown deposits we find coating carburators, and which collects in fuel injectors and on intake valves, are the highest boiling components in gasoline. They are tar-like materials which distilled along with the lighter gasoline. The best solvent I've ever seen for these was methylene chloride, but it's expensive and I'm sure it's being phased out to protect our ozone layer. In any case, if you used it on a modern car the chlorine freed during combustion would corrode the oxygen sensor. Amoco advertises a cleaner gasoline and I'm sure it's because they've reduced these tar-like compounds. All gas these days contains at least a little detergent of some sort to help keep these deposits from building up too much.

Dimethylformamide is listed in the literature as being a good engine cleaner and is "especially good at dissolving carbonaceous deposits". I haven't used this myself because it is a bit too toxic. Instead I used N-methyl pyrrolidone, which is also good.

For my tests, I tried to use a wide variety of products, well known and unknown, expensive and cheap, and also some pure solvents in order to represent a good cross section of products on the market. Note, carbon itself (such as soot and other thermally decomposed material) is not soluble in ANY solvent but solvents like dimethylformamide and N-methyl pyrrolidone do a good job of breaking up clumps and dispersing the fine particles to release the heavy tarry materials trapped within them. However, some of these solvents are too harsh to use freely in the fuel system. (Someone in one of these forums told me that when the auto industry looks for good cleaners, they mostly look for solvents that will not attack the plastic and rubber parts in the system.)

Most cleaners (the safer & slightly less effective ones) usually have common solvents in them like toluene, alcohol, acetone or methyl ethyl ketone, and naphtha. If you want to use these to clean your system, you can get more for your money by buying the pure solvents at a hardware store and mixing them yourself. I have never had a problem adding toluene, acetone, alcohol, or naphtha to my gas tank in quantities up to one quart per 16 gallons.

Most of the straight solvents I used are at least as flammable as gasoline so be careful if you use them. The alcohol used was pure, 100% isopropyl alcohol. This has no water in it, it is not the same as "rubbing alcohol".

These test results are as fairly and accurately done as I could manage with the equipment I had available, and the other data presented is also accurate to my knowledge. Your car may have different plastics in it than mine does so if you choose to make your own cleaner, do it at your own risk.

TEST RESULTS

RELATIVE EFFICIENCIES AT WHICH VARIOUS CLEANERS WILL DISSOLVE HIGH BOILING RESIDUES FROM GASOLINE AND CARBONACEOUS DEPOSITS FOUND IN USED MOTOR OIL, (10=BEST):

· 10 Gunk Gas Treatment
· 10 Toluene (a common ingredient)
· 9 Castrol Syntec Power System
· 8 Duralube Fuel System Cleaner
· 7 Gunk Fuel Injector Cleaner
· 6 Redline SI-1
· 5 Gunk Air Intake Cleaner
· 4 Naphtha (a common ingredient)
· 4 STP Fuel System Cleaner
· 4 Seafoam Motor Tuneup
· 4 Trak Fuel Injector Cleaner
· 4 STP Intake Valve Cleaner
· 4 CD-2 Emission Cure
· 4 Prolong Fuel System Treatment
· 3 CD-2 Fuel Injector Cleaner
· 3 Techron Concentrate
· 0.5 Butyl Cellosolve (a COMMONLY used "AUTO INDUSTRY DETERGENT" for oil and grease)

THE FOLLOWING CLEANERS DO NOT HURT NYLON (LISTED RANDOMLY).
(The letters in parentheses indicate how well they dissolved the material from used oil, A=best.):

· Toluene (A)
· 2-Phenoxyethanol (A)
· Duralube Fuel System Treatment (B)
· B-12 Chemtool (B)
· Trak Fuel Injector Cleaner (C)
· Techron Concentrate (D)
· STP Intake Valve Cleaner (E)
· Seafoam Motor Tuneup
· CD-2 Emission Cure
· Prolong Fuel System Treatment
· Aromatic distillates
· Naphtha
· Butyl cellosolve
· Acetone

THE FOLLOWING CLEANERS WILL DECOMPOSE THE NYLON SOCK IN THE FUEL TANK. Listed in order of increasing severity:

· STP Fuel System Treatment
· CD-2 Fuel Injector Cleaner
· Gunk Fuel Injector Cleaner
· Castrol Syntec Power System
· Redline SI-1
· Gunk Gas Treatment
· Monoethanolamine
(The monoethanolamine is the worst here. It turns nylon black on contact. It is significant to note here that the "best" "detergents" in use today are similar, strongly alkaline organic solvents). Another use for the current bunch of organic amine "detergents" is cleaning deposits out of cylinders, so I hear.

I hope this takes the guesswork out of choosing good products.

Thats awesome. I have been wondering about these fuel additives and whether they actually worked or not. this should make choosing one a bit easier. Thanks a lot for the info.

Originally posted by sciguyjim
These tests were done by me to help determine the best products

According to this test, it looks like Duralube is the best cleaner that won't harm nylon fuel system components. I do not know if my car uses nylon components in the fuel system.

Can you provide more detail on how you conducted the tests? I appreciate your scientific approach to this matter... I use the Chevron Techron fuel cleaners, but have to rely solely on their data.

defentally usefull to know :bandit:

Originally posted by JUNKPILOT


According to this test, it looks like Duralube is the best cleaner that won't harm nylon fuel system components. I do not know if my car uses nylon components in the fuel system.

Can you provide more detail on how you conducted the tests? I appreciate your scientific approach to this matter... I use the Chevron Techron fuel cleaners, but have to rely solely on their data.


To find out what's in your car's fuel system, call the mfgr's customer service dept & tell them what you want, maybe they can route you to a person who knows. That's what I did. They told me almost every kind of rubber o-ring in the system, including some kinds I'd never heard of.

The tests compared how well each product dissolved soluble gunk and how well they broke up lumps of insoluble carbonaceous material. The appropriate gunk was applied to an absorbent paper then the product was applied and allowed to soak past the spot of gunk. After a specific amount of product was applied, the distance it carried the gunk was measured.

Shit! I have been using STP for a long time now, damn, time to change!

that certainly made for some interesting reading... i've been using techron fuel system cleaner concentrate for years. one contributing factor is that a family friend of ours has worked in their marketing dept for over 20 years...

my personal observations: i always add a bottle of techron before every oil change, run the tank dry, refill, and then change the oil. i'm always amazed at how black the oil gets when i compare the oil color on my dipstick before and after techron treatments. whether or not it is the best, i do not know. it does appear, however, that it is doing something!

I keep forgetting to ask - did you test regular pump gasoline to see how effectively it dissolves your tar? If the tar is readily soluable in gasoline, this would bode poorly for using tar as the test material.

Originally posted by ivymike1031
I keep forgetting to ask - did you test regular pump gasoline to see how effectively it dissolves your tar? If the tar is readily soluable in gasoline, this would bode poorly for using tar as the test material.

No, I didn't test gasoline, but I know for a fact that tar is soluble in it, certainly at the small quantities normally present in the gasoline. Gasoline, and other products manufactured from crude oil, are a complex mixture of many thousands of individual chemicals. Because of this complexity, it is difficult to easily refine the oil to get individual pure chemicals. The complexity also makes the gasoline a good solvent for other petroleum products. Any tarlike material which is found to be insoluble in gasoline or other common petroleum solvents would have to be changed considerably form its original chemical structure and so would not be a suitable candidate for the tests.

One of the reasons gasoline has its yellow-brown color is from traces of high boiling, high molecular weight compounds containing atoms of oxygen, nitrogen and sulfur. These "heteroaromatics" are the same compounds of which tar is composed.

When gasoline sprays out of the fuel injector tip, or when the car is shut off and the injector tips get a "hot soak", most of the gasoline vaporizes as it should. However, some of the traces of tar-like materials present do not vaporize because they naturally have very high boiling points. They remain on the tip and can build up over time. They can also be polymerized by the heat to form compounds more like "coke", soot and graphite. This is the same material which can build up on the backside of intake valves. The detergents added to gasoline and changes in fuel injector design have helped reduce the chance of having problems from this buildup.

The purpose of my tests was to identify products, and some individual solvents, which can be used to clean injector and cylinder deposits. The deposits cannot be changed too much from their original structure because as they polymerize they become insoluble in any solvent.

The trick is to find solvents which are cost effective, have compositions similar to the tarlike material (in a number of features), and which will not harm the various gaskets and seals used in the car. As with most things, there isn't one best answer. Compromises have to be made with the chemical properties of the solvents and the blends of solvents used.

So, you could say the gasoline is the source of both the problem and the solution.

or "gasoline is the solution in which we find the problem?"

If none of the solvents dissolve tar better than gasoline does, why use any of them?

Originally posted by ivymike1031
If none of the solvents dissolve tar better than gasoline does, why use any of them?

Because these tar-like compounds, while having some properties similar to gasoline, also have quite distinctive properties of their own. Certain solvents with these properties may work better than the hodge-podge mixture of stuff in gasoline.

May work better... may not work better... who knows? I thought the point of the testing was to find that out? If all we know is that some of the solvents work better than others, but we don't know whether any of them works better than gasoline, then the most fundamental question ("should I ever even bother using this stuff") hasn't been answered.

For one thing, I don't have access to all the chemicals used in the store bought products (except in the products themselves), and I don't have the facilities to do testing on a larger scale. Personally, I think most of the products do help clean like they're supposed to, though a lot of people don't believe these products are necessary at all. They feel if the car is tuned properly you should do fine with just basic maintenance and good quality gas with the proper octane rating. I did accomplish my goal of rating the store bought products, at least in lab tests if not in an actual engine. Part of the reason I chose some of the pure solvents was for my own curiosity and to see if I could choose acceptable solvents by the chemical properties I thought were important. Some of the solvents were similar to the product ingredients, which, as I said, I couldn't obtain easily.

I still don't understand why you didn't test a sample of gasoline as a baseline...

I guess I should have, I just didn't think of it at the time. How would I explain cleaning injectors by doing nothing but running more gas through them?

Well if that's what the results showed, I'd assume you'd conclude that the "cleaners" were not worth the money. Based on personal observations, I'd say that even the cheap ones work better than gas, but it would be nice to have quantitative evidence.

Yeah, the cleaners are not really worth the money (which doesn't mean they don't work.) That's why I suggest buying a good solvent like toluene for about 8$/gallon at a hardware store and adding that to your tank. You get more for your money. And, It won't hurt anything in your engine because gasoline already contains toluene & other chemicals like it.

I could try to reproduce my tests to get a comparison for gas, but my "lab" is really my kitchen and I think I'd get sick of smelling gasoline fumes in my house. None of the other things tested had a smell nearly as strong as gasoline.

Basically, any engine additive/cleaner/friction reducer is usually snake oil. It's a lot like saying the whole drivetrain system, which has been continually developed and perfected over the last 150 years, is also so flawed that some little bottle of wonder goo will solve all your ills. In reality, if anything is fundamentally wrong with the design, that bottle of goo is about as likely to fix it as you are to be bitten by a rabid pig while simultaneously being struck by lightning and attacked by mutant, ill tempered sea bass.

Note: if you really want injectors to be clean, send them in for flushing. Much like rebuilding an engine or cleaning out the coolant system, ithe injectors need to be treated to a chemical bath off their fuel rail and in the presence of something other than regular gasoline. Also remember that pintle style injectors are the only ones which routinely show evidence of clogging over long time periods, Lucas disc injectors are pretty much uncloggable (is that a word?).

Originally posted by texan
Note: if you really want injectors to be clean, send them in for flushing. Much like rebuilding an engine or cleaning out the coolant system, ithe injectors need to be treated to a chemical bath off their fuel rail and in the presence of something other than regular gasoline. Also remember that pintle style injectors are the only ones which routinely show evidence of clogging over long time periods, Lucas disc injectors are pretty much uncloggable (is that a word?).

I agree. I've heard that's the best way to get them cleaned. It's just that we like to hope a quick, inexpensive method will solve our problems.

I've heard that current design injectors don't clog like those years ago.

"Uncloggable" is now officially a word. I'll give you full credit for it.

Basically, any engine additive/cleaner/friction reducer is usually snake oil. It's a lot like saying the whole drivetrain system, which has been continually developed and perfected over the last 150 years, is also so flawed that some little bottle of wonder goo will solve all your ills.

That may be true for a large number of products, but it's not universally true. I don't think that the usefulness of bottles of "wonder goo" says anything about the design of an engine either. Engines don't work very well without motor oil, do they? Why would you expect that every other bottled product performs a function already addressed through the engine design?

I don't see anything conceptually wrong with using a strong solvent to clean fuel injectors in-situ. It's certainly much more cost- and time-effective. When my girlfriend's car ('97 Civic) starts to idle rough, a bottle of fuel injector cleaner seems to fix it right up. It seems to work remarkably well - usually within a few minutes of adding the stuff to the tank, the car is idling noticeably smoother. (This has only happened twice in 125,000 miles.)

Here are some other "wonder-goo" products that don't seem like snake oil to me (besides fuel injector cleaner):
* red line "water-wetter," which, according to some of my peers in cooling system design, actually can improve cooling system performance in certain situations
* "hard block," which can be used to reinforce weak cylinder liners, and can also be used to change the depth of a cooling jacket to improve coolant flow rates in the upper (more critical) portion
* fix-a-flat
* aerosol carb cleaner
* aerosol brake cleaner
* gasoline stabilizer (for storage)
* gasoline water remover
* diesel anti-gel
* "wire drier"
* gasket dressings
* radiator stop-leak, which admittedly is not a permanant solution, is certainly better than being in a jeep, on a rocky trail 30 miles from civilization, with no coolant.

I didn't mention any of the oil additives, because I don't know which of them work and which don't. I don't see any strong reason to believe that someone couldn't sell an aftermarket oil additive that would improve the lubricating performance of motor oil, or extend its life. Oil manufacturers use additives to improve oil performance straight out of the bottle, but they face stronger price constraints than someone (even themselves) selling a secondary add-on additive package.

Interesting read... I had been looking for a test like this for some time.

Couple questions:

1. Any thoughts about why Techron (one of the more hyped and expensive cleaners) faired so poorly?

2. Any thoughts about Marvel Mystery Oil

Again - appreciate all the effort you put into this.


Clint

PS - If you send me some of the "tar" you used, I'll be happy to stink up my kitchen and see how well gasoline and Marvel do on the test.

bluetwo - my personal observations: i always add a bottle of techron before every oil change, run the tank dry, refill, and then change the oil. i'm always amazed at how black the oil gets when i compare the oil color on my dipstick before and after techron treatments. whether or not it is the best, i do not know. it does appear, however, that it is doing something!

Implies that the techron has some interaction with crankcase oil which would have to be through blowby. Perhaps the Techron helps dissolve deposits on the piston/rings that are carried off by the oil?

bluetwo - Couple questions:

1. How many miles on engine?

2. What often do you change oil and what type of oil are you running?

3. How much oil does your engine consume?


Thanks in advance,

Clint

PS: I just tossed in a bottle of techron before finding this post. Will report what it does with my car. (91 Stealth RT/TT 150K miles)

Originally posted by cbatters

Couple questions:

1. Any thoughts about why Techron (one of the more hyped and expensive cleaners) faired so poorly?

2. Any thoughts about Marvel Mystery Oil

PS - If you send me some of the "tar" you used, I'll be happy to stink up my kitchen and see how well gasoline and Marvel do on the test.

Clint,
I have no idea why Techron faired so poorly. Maybe Chevron just has a good advertising agency.

I haven't heard much about Marvel Mystery Oil, but that means nothing bad either.

The tar I used was ordinary tar from a local hardware store. I said I used a worst case sample. I'm sure both the gasoline and the Marvel will dissolve the tar, but the gas will dissolve it faster and more thoroughly, especially at room temp. This is because it has a thinner consistency and has smaller molecules. The oil would have to be heated to dissolve much of the oil in a short time. If you start heating oil and tar, do it gently in a sealed container or in a place where you have ventilation, and don't use open flames or exposed heating coils. You shouldn't need that much heat anyway.

I personally prefer Royal Purple and Lucas, and have been using them for at least 5 years

I guess I should have, I just didn't think of it at the time. How would I explain cleaning injectors by doing nothing but running more gas through them?
That works too.
Other independant injector cleaner tests have showed that NO aftermarket chemical cleaners will work well.
Only physical means like abrading the material or sonic vibration will work.

I have a car that spent a large part of its earlier life sitting, and one of its two supplemental injectors (it's turbocharged) got a bit gummed up and would leak into the intake plenum after the engine was shut off, made it hard to restart, and it would run bad until the fuel was cleared out of the plenum.
I might add that the offending injector looked perfect on the outside.
Sent both my injectors off to an injector specialist and they cleaned them utrasonically.
They came back looking exactly the same on the outside, but work spiffy.
Well worth the $60 I spent.

I personally prefer Royal Purple and Lucas, and have been using them for at least 5 years

Wow, so you've been using them for almost half as long as this thread had been dead!

-Rod