So I just got a fuel system flush done at the dealer, which was the last thing left on my major tune up list. I have always been a big proponent of getting fuel system flushes done every 30-40k miles as part of a regular maintenance schedule. However, all of my cars and customers cars have been well cared for and/or low miles so I never really felt any difference before/after the service. My 96 LS is the first car I have owned with over 100k miles since I was 17 and I bought it knowing full well I needed some major TLC. There were no service records and the PO probably wasn't the best owner in general. So I went about replacing everything that could be replaced and I noticed a little increase in pep and smoothness.

Fast forward to this Monday when I picked up the car from getting this service done. I was instantly amazed at the difference in tip-in and how much smoother the idle was just sitting in the parking lot. It also startered faster and crisper than normal. Biggest difference came when I went to pull out onto the street and make a gap in traffic. Before, there was a distinct lag between the initial rolling onto the gas and any sort of response followed by some lazy acceleration off the line; suddenly it was almost instantaneous response and a much more urgent acceleration. I'm not taking smoking the tires and drifting it out of the parking lot sort of response and power, but if you know your car well, it's a VERY obvious difference!

This is definitely a service a lot of people pass over as cars age, but one that can make a huge difference in restoring a lot of the lost pep and smoothness, as well as fuel economy. Certainly worth the $130+tax that I paid, the dealer even covered $50 worth of taxi rides from and to the dealer.
I'll probably do it again in the spring just to make sure everything is at 100%.


For those that are not familiar with this service, basically you run a mixture of gas and a strong but combustible solvent through the fuel system with the engine running. The benefits of this are removing varnishes that can build up in the fuel lines and injectors restricting flow and compromising the atomization of the fuel from the injector. If the injector is not properly atomizing the fuel, you are getting poor fuel mileage as you won't have an even burn in the cylinder. This service dissolves and removes even small particles of debris that can slip past the filter and plug an injector. As a by-product, this service also acts as an intake flush cleaning out carbon and oil deposits down the ports and off the valves, the piston crowns, combustion chamber and exhaust ports. It will also help clean and increase the efficiency of the catalytic converter and extend the life of plugs and O2 sensors.

There are a bunch of different brands but the good ones all use the same basic method: the fuel feed line is disconnected and connected to the machine and fuel is pumped into its reservoir, the concentrated solvent is mixed with that fuel. The cars feed and return lines are joined, so the fuel from the tank is just cycled back, while the machine is connected to either side of the rail. The car is then started and run off the machine for 30-60mins while watching the temp and aggressively revved up to dislodge any carbon while soaking the cat to clean it up.

Should be pretty interesting to see the differences in fuel economy over the next few months. This tank is going to be rubbish as the service uses a good chunk of fuel out of your tank while putting on zero miles.

 

Interesting. Post some numbers. All you have to do is pull the negative for 30 seconds for a soft reset.

 

I keep my fuel log on my phone and have tracked it since I got it over a year ago. I drive 98% in city and have fairly erratic mileage from tank to tank based on the type of trips I take.

Over the last 3months I have averaged ~16L/100km, with one low of 11.61 and one high of 19.02 L/100km.
Under my normal driving conditions I average between 15-17.5 L/100km per tank. Random outliers are peppered about due to substancially more highway driving than normal or lots of short trips from cold.

I'll be filling up in the next couple of days and will reset the battery then!

 

SOP. my 95 LS always runs better and smoother after a good wash n wax..

 

Glad the fuel system service helped.

Stateside gas for the most part is pretty good. On another forum, one of the members was a chemist for ARCO. He gave a good discussion about the detergents/additive packages in gasoline. In combination with the mechanic we use, it bears out that he seldom sees fuel related issues here. This comes back to using premium as specified. The programming will adjust for lower octane gas and he cautioned me to not do that long term. YMMV vary of course and fr what I put into the tank, I have no complaints.

The obvious change in ours came when replacing the ECT sensor. It is getting MPG comparable to when it had 60K miles on it. I'm looking forward to a long trip to see if it will touch the 26.X MPG range again.

 

u will not get better mileage with 92 than 89..especially buying low grade premium fuel,dont buy gas where u buy food

 

^so is costco gas bad?

 

http://www.toptiergas.com/retailers.html
not sure who Costco gets their gas from, I run it in my corolla but not im my lexus..I do however use 89 or 92 from chevron...76 or Valero. and I don't see Valero on that list..i always thought it was a better grade gas...ugh

 

Quality of fuel is dependent on many things. You can get great fuel out of a horribly maintained tank and get a host of problems. I've seen one bad tank of gas completely plug a brand new fuel filter and wipeout a fuel pump. A lot of fuels come from the same source, the difference is the additives and the level of cleaning they go through. Gas from non-chain stations is usually just generic stuff with minimal cleaning and some but often no additives.

Up here, all the fuel from ALL statons comes from the same place. Be it Shell, Chevron or Essso(Exxon) and all of the smaller stations. The difference is that specific companies specify their own chemistry and processes where as the others essentially just buy from a menu. Up here, Costco gets the same fuel as the little stations which isn't as clean compared to Shell or Chevron. The only difference is that Costco tends to take better car of their holding tanks than the smaller stations.

 

All fuels, if let sit for extended periods of time, will begin to varnish up and leave deposits. Often a lot of these deposits and varnishes from the gas station and when you fill up. The settling time for fine particulates in still fuel is ~0.75-2days depending on size. As a general rule, you should never fill up at a station that has had a few delivery within the last day. The filling of station tanks disturbs all the crap at the bottom of their tank and is how you can plug a brand new fuel filter in tone tank of gas!

Generally speaking, the older the station, the dirtier the tanks.


Regardless of the fuel quality or origin, this fuel system service is still highly recommended even if you use a super clean high quality fuel.

If nothing more, think of it as a simple injector cleaning and cat/plug/O2 service.

 

i know the costco here has a very high turnover rate. always line ups at the pump. I havent noticed any difference between costco 93 and shell 91.

 

In my Lexus I don't notice really any difference between RaceTrac, Shell, or BP. We have 93 here in the South, which I always use. When I tuned my old mustang I had the most success with BP but they are significantly more expensive in my area. For the most part, I use RaceTrac.

 

You likely will never notice the differences between brands unless you get a bad tank of gas or are exceptionally **** about tracking your mileage and have zero variation in the trips you take.

However you will still see a difference between before and after with the fuel system service, if you have a large enough sample size.... If you just bought the car, you won't have enough data to be able to accurately see a definitive increase in mileage. HOWEVER, you will be able to feel the difference in smoothness and response if your fuel system is dirty.

 

As far as gas goes, we mainly use Chevron, BP, or Mobil. I fill the car up with the "mid-tier" gasoline which is ~89 octane and I get an average 20.6 MPG on the little diagnostic display. This is with a little "coaxing" though, and the speeds on the roads I drive on range from 30mph-60mph.

 

i'm a bit skeptical in this service as it may just be a placebo effect. it is also a possibly that the dealer reset the ECU when the battery was unplugged and the car is just relearning your driving habits. only time will tell if there is indeed an actual change. please keep us updated, and sorry for being a devil's advocate.

i do agree fuel qualities vary between regions. the highest octane we can get here in my city is 100 (race gas), then it bumps down to 91.