Any body have good data on the Yaris fuel system?

[LtNoogie]

I've done my pdf searching through the posted 2007 Service Manual and this is all I've found.

We should be measuring 44.1 to 49.7 psi with the engine idling. This is regulated fuel pressure because the manual says to check the vacuum sensing hose and the fuel pressure regulator if the measurements are out of spec.

Anybody know where the fuel pressure regulator is? Incredibly the service manual does not show a picture of the thing or where it is in the car.

Anybody know what the unregulated fuel pressure is straight out of the fuel pump?

I cannot find anywhere in the manual what the static fuel flow capacity is of our OEM fuel injectors. Anybody have that number that can be referenced? Better yet, a specification or data sheet for the OEM injectors?

I would like to work from specified numbers or first-hand measurements. Anecdotal references won't work for me in this case.

Thanks

[kurokoma-kun]

From the Fuel manual...

"Injection volume: 47 to 58 cm3 (2.9 to 3.5 cu in.) per 15 seconds" (page 17)

To clarify my remarks in another thread: this works out to 212cc/min--using an online calculator to get max hp for this injector volume, I got 130.

[CTScott]

The fuel pressure regulator is part of the fuel pump assembly. If you remove the fuel pump/sender gauge from the tank the regulators is pressed into the pump with and o-ring.

[LtNoogie]

Originally Posted by kurokoma-kun

From the Fuel manual...

"Injection volume: 47 to 58 cm3 (2.9 to 3.5 cu in.) per 15 seconds" (page 17)

To clarify my remarks in another thread: this works out to 212cc/min--using an online calculator to get max hp for this injector volume, I got 130.

Thanks for finding that. I guess I need to learn how to work those calculations for myself.

Originally Posted by CTScott

The fuel pressure regulator is part of the fuel pump assembly. If you remove the fuel pump/sender gauge from the tank the regulators is pressed into the pump with and o-ring.

That's not good for what I wanted to do but thanks for the information.

[kurokoma-kun]

Originally Posted by LtNoogie

Thanks for finding that. I guess I need to learn how to work those calculations for myself.

I wish I could learn how, but I am not good enough at math--as far as things like the max hp I have to rely on a calculator to give me the answer. If the numbers are off I never know why so I can't tell a good calculation from a bad one.

Even if I get the scientific concept or whatever, even if I memorize the steps to solve, the simple arithmetic takes me a very long time and the results typically don't mean a thing I'm kind of in awe of math geeks for whom the numbers make some intuitive sense.

Are you one of those freaks, Long? Then maybe you would like to d/l the demo of this--a sophisticated looking fuel injector calculator for windows.

http://www.performancetrends.com/Fuel_Injector.htm

[LtNoogie]

Originally Posted by CTScott

The fuel pressure regulator is part of the fuel pump assembly. If you remove the fuel pump/sender gauge from the tank the regulators is pressed into the pump with and o-ring.

I read practically the entire FUEL part of the service manual but never found a reference to the fuel pressure regulator being there. Do you have another source or did you find it by taking out your fuel pump assembly?

If the regulator is part of the fuel pump assembly, then I can never get any pressure out higher than what the regulator puts out, right? I was hoping that the regulator would be a standalone unit away from the pump that I could replace with an adjustable in-line regulator that could give me higher pressures under certain conditions.

Thanks for your thought on this.

[LtNoogie]

KK,

This is some complicated stuff! But I'll post what info I've gathered so far from the service manual.

Fuel pressure: 44.1 to 49.7 psi. So to make things easy, average fuel pressure = 46.9 psi

The way the test diagram is depicted, it appears that the injector is being tested at a 100% duty cycle for 15 seconds.

Injection volume: 47 to 58 cc per 15 seconds = 188 to 232 cc/min. If we take the average, that comes to 210 cc/min @ 46.9 psi.

Now to find a calculator that tells us what size injector is needed. Problem is that many of them ask that you input the desired crank horsepower. So what do we enter? 130hp? 140hp? I have no idea what to enter here.

Others are fancier and ask what AFR are we looking for at the highest RPM...11 @ 6400?...12 @ 6400?

Oh yeah, another fancy calculator factors in BSFC. Brake Specific Fuel Consumption is the amount of fuel consumed (in lbs. per hour) for each horsepower made. This should be .45 to .50 for naturally aspirated engines, .55 to .60 for supercharged engines, and .60 to .65 for turbocharged engines.

No wonder people do a lot of trial and error as part of their "tuning". I'll keep reading until I feel I understand this stuff.

[CTScott]

Originally Posted by LtNoogie

I read practically the entire FUEL part of the service manual but never found a reference to the fuel pressure regulator being there. Do you have another source or did you find it by taking out your fuel pump assembly?

If the regulator is part of the fuel pump assembly, then I can never get any pressure out higher than what the regulator puts out, right? I was hoping that the regulator would be a standalone unit away from the pump that I could replace with an adjustable in-line regulator that could give me higher pressures under certain conditions.

Thanks for your thought on this.

I got the info from TIS, as Cammell mentioned. Shoot me a PM with your email address and I'll email the newer fuel section.

I think you could pull the internal regulator and put your adjustable regulator in-line.

[CTScott]

Originally Posted by camelll

You buy the whole year ct?

I subscribed to TIS, so I have access to all vehicles, all years (until my subscription runs out). I can grab sections and paste them into a Word doc, or print them to PDF. It is mighty painful to do, as every section is separate link (i.e. for the fuel section alone there is: injector, injector components, pump, pump components, sender gauge, sender gauge components, ...)

Lately, I've been reverse engineering the Prius rear wiper - Soon, I'll have a DIY on enabling intermittent for our rear wiper...

[CTScott]

Originally Posted by camelll

Nice thanks for the help with this and all of the other projects you help out on, seems to be a lot.

No problem. I'd really like to see this one solved, as after watching peterpoop's movies, I am saving my pennies. I really don't need the extra oomph from my Yaris, but I'd really like the sound. With my supercharged Xterra, you really have to listen closely to hear the difference from a NA one.