Fuel Rail Flush Results

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Jeff Williams
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Fuel Rail Flush Results

Postby Jeff Williams » Thu Jul 10, 2003 2:17 am

Here is an update for you.

If you remember, I had some bad gas, and it caused my car to run rough, so I added some fuel treatment, and you guys gave me the advice to check all the fuel injectors, and sensors, then get the fuel rail flushed.

Well, I did it, and the car idles much smother, and I am getting about a 10% better fuel economy.

I went from around 19.8 MPG to 21.9 MPG!

I have put about 2000 miles on the car, since i had it done, and I am very pleased with the results.

The flush cost me $113 at the dealership, and they checked all the sensors, and did a power balance check.

All of m ydriving is highway driving, at 78 MPH, with about 5% of my driving, in neighborhoods, and in town.

Here's the old thread:

http://www.nissaninfiniticlub....24186


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DAEDALUS
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Postby DAEDALUS » Thu Jul 10, 2003 2:17 am

Great to hear. I've been measuring good mpg improvements too, but I only fill up around 2x a month, so I'm waiting for more data before feeling too confident in the results.

Q45tech
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Postby Q45tech » Thu Jul 10, 2003 2:17 am

Just an annual event on mine along with a fogger plenum runner TB clean and a hand wipe of the bottom of the TB and hand clean of the MAF screen, when I change the air and fuel filter........every May/June.A can of BG 44k prior to each 90 day oil change and the above will usually keep the idle perfect and the power as much as possible considering mileage.

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Jesda
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Postby Jesda » Thu Jul 10, 2003 2:17 am

Awesome, Jeff! After adding a can of B12 Chemtool I noticed significant mileage improvements as well, about 2mpg, and idling is far smoother. Next step: Rail flush!

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Jeff Williams
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Postby Jeff Williams » Thu Jul 10, 2003 2:17 am

Yes, a quarterly soaking of the MAF with brake cleaner has done wonders for the idle smoothness, as well. I didn't see much change in the mileage, but if I let it go too long, the car starts to load up and run like an American car.

airman
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Postby airman » Thu Jul 10, 2003 2:17 am

hm.. on my 96K 97Q after recent BG service I didn't notice _any_ changes. Not that I was complaining about anything but I was expecting some effect. Was it done at all? :D

Right after service my mileage was: first tank 17.5, second 19.9 with mixed driving (higways prevail though). Somewhat low for the second gen Q. Is it a good idea to replace sensors and may be thermostat?

$113 including power balance test? It's very good. I was charged 120 and no balance test. They asked another 100 for it.

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re: bad fuel mileage

Postby powerdrifter » Thu Jul 10, 2003 2:17 am

I don't think you're getting the best possible mileage out of your car. I have an '89 240sx w/ KA24E SOHC, HyperGround Kit, Magnecor ignition wires, SplitFire 3xPlatinum plugs, port/polished head, throttle body, intake plenum, manifold (removed SCV valve (secondary butterflies)), air filter adapter, polished MAF sensor (only on main air inlet), Hotshot Headers (and gasket are port-matched to the head), ThermoTec exh. wrap, Random Tech cat, new 180SX fuel pump/in-tank filter, new 195cc injectors, 300ZX fuel filter, Injen intake, HKS Super Mega Flow air filter, and STOCK EXHAUST (race exh. is for the races only, cops y'know). Everything on the car is in excellent condition, sensors, valves, vacuum hoses, car is driven hard but very well maintained. According to my measurements, I'm getting about 26MPG. How accurate are my measurements? Simple, do the only way possible to find the exact figures. You get two (2) separate 1gal. gas containers, drive your car until it's empty, RESET THE MILEAGE COUNTER, add 1gal ONLY, and Drive you car on the freeway. Where I live, it's 30-35 miles to Downtown Los Angeles, and I had to go anyways because it's the only place that I could find that carries the newest Japanese race/drift videos and mags. I ran out of gas exactly 26 miles later doing 85-90 on the fast lane with light traffic on a Saturday, took me about 25 min. getting there. Now use the other gal. of fuel to get you to a gas station. This is just my personal experience that I pass on for others to read. Hope it helps you in some way. [email protected]

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lessthanjakejohn
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Postby lessthanjakejohn » Thu Jul 10, 2003 2:17 am

For powerdrifter: That is a waste. Fill up your tank. Reset tripo. Drive till its time to fill up. X - Y = Z X- Z = B M/A= AVG Mileage.

X = Total tank. Y = amount of gas in Z = Amount of Gas left. B= Amount of gas spent. M= Miles traveled during that time.

That way you get a better avg of a week- two weeks of driving. But then perhaps a Q has an fuel / mileage counter builtin on the car?

BTW, do you think his mileage is bad? He has a 4.5 liter V8.

???

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Jeff Williams
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Postby Jeff Williams » Thu Jul 10, 2003 2:17 am

Quote »BTW, do you think his mileage is bad? He has a 4.5 liter V8.[/quote]

AND our cars wiegh 5,200#!!!

My mileage fluctuates from tank to tank, but I think that is caused by me trying to get to the next even dollar ammount, when filling up.

I don/t EVER want to run my car out of gas. Who knows what is in that last 1/5 gallon (water, dirt, dead animal parts,...)

I use the NASCAR approach, which is the same as lessthanjakejohn suggests.

BTW, the car is still getting over 20 MPG, on every tank, with a few 22 MPG tanks. Overall the average has been 21.3, which is still an improvement.

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AZhitman
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Postby AZhitman » Thu Jul 10, 2003 2:17 am

Big difference between what constitutes a good idea to a 240 owner and a good idea to a Q owner.

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90Q45blue
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Postby 90Q45blue » Thu Jul 10, 2003 2:17 am

Agreed, plus, no one buys a Q for its great gas mileage. :)

Nick

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elwesso
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Postby elwesso » Thu Jul 10, 2003 2:17 am

True that!!!

I just divide the number of miles (trip meter) by the number of gallons I put in the car...... (miles per gallon)...... Is that wrong???

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sultan
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Postby sultan » Thu Jul 10, 2003 2:17 am

my car is running rich (i hope the bad knock sensors are causing that) and i've got a lead foot so gas mileage doesn't exist for me. i'm happy when i get over 17 mpg. good gas mileage is what the bike is for, i get 40 mpg in the city, no highway because the gearing is horrible and it leaks oil when held at constant freeway speed. hmm, maybe that's because all the engine gaskets are 23 years old...

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lessthanjakejohn
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Postby lessthanjakejohn » Thu Jul 10, 2003 2:17 am

elwesso wrote:True that!!!

I just divide the number of miles (trip meter) by the number of gallons I put in the car...... (miles per gallon)...... Is that wrong???


hahahahaha. Yes that is what I was trying to think of earlier... The simple way.

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elwesso
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Postby elwesso » Thu Jul 10, 2003 2:17 am

To be honest, I went through all that trouble to find out that the numbers were the same using my way and your way........ But mine is a tad easier!!!!


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