How good is using a fuel system cleaner?

[pavanbabut]

Hi guys,

Did anyone of you ever use a fuel system cleaner that are in market?

If so, how good are they in cleaning the system?

Any side effects of using it?

If everything is good, which brand is good?

I always use Valvoline for all kinds of fluids in my car.

Here is the complete list of products for fuel system

Valvoline Fuel System Additives

Lemme know which are good and better to use.

-Pavan.

[svxsubaru1]

The strongest and best bang for the buck that you can buy to clean a fuel system would be xyloeine( spelling?) You can find it at a any paint store or a home depot like store. It comes in 1 gallon containes for around $10. Its also a great octane booster, but you have to remember to add a couple of onces of ATF fluid when you use it so it won't dry out your seals. I For got the best ratio for xyolene to gas iam sure some one on here will know.

[SilverSpear]

Originally Posted by svxsubaru1

The strongest and best bang for the buck that you can buy to clean a fuel system would be xyloeine( spelling?) You can find it at a any paint store or a home depot like store. It comes in 1 gallon containes for around $10. Its also a great octane booster, but you have to remember to add a couple of onces of ATF fluid when you use it so it won't dry out your seals. I For got the best ratio for xyolene to gas iam sure some one on here will know.

You put two drops of ATF in your gas tank???? what about destroying your injectors???

[dcarrb]

There are "fuel system cleaners" in whatever brand of gasoline you buy. Anything else you dump into your fuel tank is a waste of money.

dcb

[n00b on demand]

When your tank is almost empty dump some toulene or xylene into the tank and then fill it up with gas. Very good for cleaning the fuel system. Like it was said before....pick it up at home depot or a store like that.

[pavanbabut]

Thanks for ur replies.

So wht all u guys mean is, stay away from those products and it is always better to use toulene or xylene to clean the system effectively. Right?

If So can someone gimme the ratio of addition?

-Pavan.

[Darksied-X]

Here's the big toulene\xylene\fuel additive thread from a while back. It should have all the answers your looking for: http://www.subaru-svx.net/forum/show...hlight=toulene

[mohrds]

No gas additives will do anything unless they are strong enough to damage other things.

From http://www.asashop.org/autoinc/june98/techtotech.htm

Fuel Injetor System Service
(Note the words "system" and "service" in the subtitle, and not "cleaning!")

The proper steps in fuel injector system service are:

Check fuel pump operating pressure and volume.
Test pressure regulator for operation and leakage.
Flush entire fuel rail and upper fuel injector screens to include pressure regulator.
Clean fuel injectors.
Decarbon engine assembly.
Clean throttle plate and idle air control (IAC) passages.
Check minimum air flow rate and adjust if needed.
Relearn onboard computer.
All eight steps may be performed using one of the "two-line" fuel injector service units. (Carbon Clean, Injector Test, DeCarbon and Motor-Vac, to name a few.)

Check fuel pump operating pressure and volume
The missing link here is volume, as most working technicians assume that if the pressure is correct, the volume is OK also! By hooking up a fuel pressure tester to the fuel rail inlet and return, and using the pressure side feed t-Ed into the fuel unit, we can quickly test the fuel pressure with engine running but also at the same time test the volume of the pump by stealing fuel into our holding tank (one pint in 30 seconds is the usual specification). When proper volume is flowed into the tank, we would shut down the engine and change hose connections to allow the machine to be put in control of the fuel supply system. The two line system would be attached to inlet and return on the fuel rail, with the vehicle's onboard system being "looped" and returning fuel to the tank. This prevents disabling of the factory unit.

Test pressure regulator for operation and leakage
At this time, the regulator would be tested for operational pressure and proper regulation including leakage. (This works well as the operator has total control of rail pressure with the unit control valve.)

Points to Ponder:


Good pressure doesn't mean proper volume! Example: A clogged filter may test OK on pressure, but restriction may not allow proper volume under load!
There is some logic to using the vehicle's gasoline to service the system as opposed to a can of shop gasoline that has been around for some time!
Pressure regulators do fail and a lot more of them don't properly shut off the fuel, causing higher-than-normal pump wear and shorter life!
Flush entire fuel rail and upper fuel injector screens to include pressure regulator
At this time, I would suggest raising the input pressure to a point above the regulator setting to allow a constant flow of fuel through the inlet pressure side of the system - through the fuel rail and out the open fuel pressure regulator. In most cases, the apply pressure is 75 psi to 90 psi but will be maintained by the presence of a regulator. At this point, a cleaning chemical is added to the fuel mixture at a 5-1 mixture and allowed to flow through the system for 15 minutes to 30 minutes. (I have some GM dealers that use one hour per vehicle with great re-sults!) Results are best on a hot engine, and fuel supply is looped with the vehicle's engine not running.

Points to Ponder:


This flush is the "fix" that most vehicles needed to begin. The difference is that you are effectively removing the deposits to a remote tank and filter vs. attempting to soften and blow through the upper screens.
Most injectors use a 10 micron final screen.
A 25 percent restriction in the upper screen would increase the injector on-time approximately 25 percent!
Injectors have a working "duty cycle" like a welder. Extending the duty cycle equals a shortened life of the coil or bobbin.
Each engine has a "pattern failure" in the system. Example: Buick V-6 engines have problem injectors on the rail curves and the injector next to the exhaust gas recirculation (EGR) valve. Those three injectors will always show a restriction to flow first! Cylinder No. 5 is the pattern failure on 4.9L Ford in-line 6s. (Study the rail design and look for the problem areas.)
Clean fuel injectors
At this point in the "service," we start the engine and adjust the output pressure somewhat closer to regulator pressure or somewhat lower. Adjusting lower will cause the pulse width to open up somewhat longer and allow the injectors to be cleaned. Slow speed (idle) position will take a longer time frame and operating temperature will be reached. This is one place where time is required. Did you ever wonder how a can of injector cleaner could clean the entire injectors in nine minutes? (It can't!) Remember, not only do we want clean injectors, but we also want the chemical to decarbon the engine valves, pistons and O2 sensor.

Points to Ponder:


Time is required to perform this service.
Internal pintle cleaning is performed during this cycle.
Fuel control is always in direct response to O2 response. Example: Slow O2 = slow fuel control = poor performance.
Decarbon engine assembly
On most vehicles, the injector spray is going to help the decarboning process. On others, we may need to enhance the operation with an external addition of mixture through PCV hoses, throttle plates or idle air controls.

Points to Ponder:


Most technicians (especially very young ones) think carbon is a 1990s problem. The older guys (especially the very old ones) remember throwing rice through a flathead at 2500 rpm and watching the black specs fly out of the exhaust. This is still a problem in the '90s (although rice is not suggested). We have a lower fuel volatility, and in some cases too high of a compression may cause a no-start situation.
Proper compression = 14.6 x compression ratio.
Clean throttle plate and idle air control passages
Just this "service" alone on most late model engines will show a manifold vacuum increase of up to two. You may stop the engine and clean the areas as needed, but my suggestion is to use an extra hand-held fuel injector hooked in parallel with the pressure hose along with a pulser to allow a cleaning of throttle plates with the same chemical as the injectors are running on. This has proven to work very well as air drawn into IAC passages on a running engine will clean the passages without IAC removal. Neat trick!

Points to Ponder:


A manifold vacuum increase tells the technician that the engine "liked" the service.
Using the hand-held injector usually will lower a General Motors IAC count from 40 to 15 without touching a thing! (Think about this.)
Check minimum air flow rate and adjust if needed
Most vehicles' "stall" problems are due to a misadjusted throttle plate or incorrect minimum air rate. Check service manuals for specs.

Points to Ponder


ACDelco makes a set of small "tuneup" booklets that do an excellent job of covering minimum air rate adjustment procedures.
Relearn the vehicle's onboard computer
Some vehicles may have been running in such a poor state of operation that the onboard computer may need to be relearned! Consult the OEM-suggested relearn procedures per make.

Fuel injection system service is complete! This "service" usually takes approximately one hour for the vehicle to run out of fuel and the entire service to be performed. The good thing is that the technician may do other services while this is being performed! Some of my customers put in a set of plugs while the engine is flushing or change the fuel filter or do the brakes. Charges are up to the individual shop, but the performance gained is absolutely amazing.

In reality, all you are doing is exactly what should be done with mileage, and that is restoring the system to original operations.

Jim Linder, owner of Linder Technical Services, Indianapolis, Ind., oversees an automotive technician support facility that provides equipment and technician training programs to the Indiana marketplace. Linder Technical Services has six training sites in Indiana.

[dcarrb]

Originally Posted by pavanbabut

Thanks for ur replies.

So wht all u guys mean is, stay away from those products and it is always better to use toulene or xylene to clean the system effectively. Right?

If So can someone gimme the ratio of addition?

-Pavan.

Really, what makes you think your fuel system needs "cleaning?"

dcb

[immortal_suby]

Though the injectors themselves may not need cleaning, if you have ever taken the intake off of an svx you will see that there is a ton of black gunk built up in the runners. The IRIS valve butterfly gets some gunk on it too. It would definitely benefit from a good cleaning.

The subaru tech tells me the cleaning they do is not just a pour in the tank one. They spray something into the intake as the car is running to eat up all the gunk buildup.
I like to get in there when I have the intake off with a good throttle body cleaner and get it all nice and clean and remove the IRIS and clean that section out real well. The EGR is usually pretty caked up too.

[thundering02]

yeah I used to have a can of intake cleaner with my teg and just spraying it in and you would see some black stuff drain out. makes me wonder about the rest of the system and thats why i use cleaners....I use the 104+ "off road only" kinda stuffs

Well, after I got my new[ish] engine installed, the car would sputter at idle. I threw a gallon of xylene in with the second tankfull. It idles perfectly now. Could I have gotten a bad batch of gas? Yeah, possibly. Maybe the engine had deposits in it, from sitting in a crate for a while.

[pavanbabut]

Originally Posted by dcarrb

Really, what makes you think your fuel system needs "cleaning?"

dcb

Hi,

The thing tht makes me to clean the fuel system is, I am sensing some rough idle sometimes when i press the accelerator a little bit (very little) means the rpm needle is dancing around 1k at tht time. The other thing is sometimes while idling i am sensing some shake/movement (or whtever we call it) in the car while i am in drivers seat. Last but not the least, Bad gas mileage.

I am not having tht much time to clean all the things (fuel injectors, fuel lines, pump etc) by removeing one by one. So i am thinking whether these products can do some good (not full perfect) and make things atelast a little better.

Hope i am clear in my doubts.

-Pavan.

[pavanbabut]

Originally Posted by immortal_suby

Though the injectors themselves may not need cleaning, if you have ever taken the intake off of an svx you will see that there is a ton of black gunk built up in the runners. The IRIS valve butterfly gets some gunk on it too. It would definitely benefit from a good cleaning.

The subaru tech tells me the cleaning they do is not just a pour in the tank one. They spray something into the intake as the car is running to eat up all the gunk buildup.
I like to get in there when I have the intake off with a good throttle body cleaner and get it all nice and clean and remove the IRIS and clean that section out real well. The EGR is usually pretty caked up too.

Hi,

If you dont mind and if you can make some time, can you tell me how to do this stuff. I am little bit inclined to do this if I can do it in some reasonable time.

thanks,
-Pavan.

[dcarrb]

Pavan,

Please understand: I'm no expert. Some folks will swear on their grandmana's grave that this or that fuel additive is the greatest thing since sweet iced tea, but I am exceedingly skeptical that anything you pour into your tank will cure the symptoms you describe. (I suspect a "silent majority" here would agree.) It's highly unlikely that any component of your fuel system needs cleaning. Gasoline is a potent solvent. If an injector is to blame, it probably needs to be serviced or replaced.

As to cleaning the intake as some have alluded, that's a completely different issue. No fuel enters the SVX intake, so obviously, nothing you dump into the tank will make any difference here. The intake can indeed become gunked-up by crankcase vapor byproducts and airborne debris, but again, the likelyhood of this having an obvious detrimental affect on your car's performance seems minimal.

dcb