Fuel Pressure regulator

[jamiemirror]

No Filh, I'm not so expirienced.
I will suggest as first buy the ZT2 wideband kit from Zeitronix. After that you just can monitor your fuel ratio in real time and think what exactly must be done. One interesting ideia from USA ITB entusiast - he just uses TVIS signal to manipulate water temp. sensor value (as I remember - add 10kOhm to the value) - that way the ECU was fooled to enrich in RPM over 4500. Normally ITB setups with stock ECU are running lean in higher RPM.

In general - KN is good, adj. fuel regulator is cheap mod - and ZT2 is nesessary (if you don't have dyno - I think all we haven't because we are enthusiasts and have no extra money for continuous dyno-tunning). The TVIS-trick will work for you also - but only if needed (see ZT2 data log).
Note: If you overrich mixture over 12:1 - this will robber your power. Try to keep AF ratio 12-14:1 (WOT- at least 12.5:1).
PS:If you use stock 10angle base ignition advance - try 16angle one.

[Mux213]

filh,

A mate of mine has a garage here in NL and does alot of supra work. You might want to send him an email for supra parts. His website is
http://www.supras.nl

[nmwisima]

No, I didnt explained my situation very well.

oem gZe running at 0,55 bar boost and about 2,5 bar fuel pressure at idle, right?
I use a larger pulley, STi pump (240 lit/hour) and fuel pressure regulator and run 0,86 bar boost with 3 bar f.p.

BUT, when fuel pressure is 3 bars at idle, it suppose to go up when on full throttle.
I was told that the electrically controled original f.p. regulator can automatically increase f.p.
That means that if you adjust f.p. at idle at 3 bar (instead of 2,2) when on full throttle fuel p. suppose to raise up to more than 4 bars and boost pressure also raise up to 0,95 bar because MAP sensor can do that.

Well my problem is this:
Are the above right? Electrically controlled f.p.regul. can indeed automatically increase pressure at full throttle?
Does the MAP Sensor indeed reads more fuel and gives more boost?
and finally,
Why am i running just 2,2 bar fuel press at idle with oem regulator???

[nmwisima]

hey jammie where are you???????????????

And others plz..................

[jamiemirror]

@ nmwisima:
I was outside to take a walk with my daughter :-)
http://www.billzilla.org/4agstock3.htm

Quote:One last important item is the small rubber pipe that goes from the inlet manifold to the fuel pressure regulator. What it does is this - When there's a high vacuum, as you get at idle, it alters the regulator so that it has a little less pressure. When you open the throttle, the manifold pressure quickly rises a little, and as a result the fuel pressure also rises a little, thus making a cheap & effective accelerator pump. The engine will work just fine without that rubber pipe though.

This is interesting explanation about "2.2 bar pressure at idle" case.

Quote:oem gZe running at 0,55 bar boost and about 2,5 bar fuel pressure at idle, right?
I use a larger pulley, STi pump (240 lit/hour) and fuel pressure regulator and run 0,86 bar boost with 3 bar f.p.

When GZE engine idles - the fuel pressure will be again 2.2 bar (because of VAC). When GZE runs 0.55 bar boost - the fuel pressure will be somewhere 3.05 bar (if we measure 2.5 bar on NA engine + boost pressure). The main ideia is to increase injector flow via fuel pressure instead of injector size. This can be done in limited (~10-15%) borders. So in described situation if we run idle at 2.5 bar instead of 2.2, NA will be 2.8 and boosted - 3.35 bar.

PS:4AGZE uses electic supercharger clutch and some electric air valves but I'm not sure about electric valve for fuel pressure regulator - I just haven't info about this regulator from GZE engine.

[nmwisima]

i am not sure all these are true, those are the words of the previous owner who also made the transplant of the gze on my AE.

hE SAIS that with more fuel pres at idle (let's say 3 bar), it can go up to 4,5 bar on full throttle and that will give the compressor the opportunity to raise the boost at 0,95 bar!!!!!!!!!!

Don't know

[filh]

Thanks again , Mux 213 and Jamiemirror , I'll check all this in a few days
just waiting for the Ebay auction on injectors (green from ae92).
And I'll of course check your interestings links .
There are so many informations on this , but not easy to find the right way in! As you said , where are fans first ! And I think to be one , as I ran
Toyota in rallies for about 27 years now (some unfaithfullness with a GM Manta and a Nissan 160j SSS) . Toyota Ta22, Corolla Ke30, Trueno(old school) Corolla Te72 , and now Ae86....
Big Toys for Big Boys
Phil Filh

[alimonos]

"You will probably need some piggy back electronic unit (such us super afc2 or e-manage) so why spent money on fuel press regulators. "
How does this work, where is it connected and of course ... cost?

[jamiemirror]

Cost must be the first issue in this case :-)))
But if I would use piggy-back - maybe Megasquirt (standalone) is more logical choice - from USA assembled and tested units starts from $250.

[NoHachi]

Hi everyone,
Just a few remarks from me, but I'm just going on common sense. I haven't had any experience with a 4A-GE specific fuel system.

1: nmwisima's fuel pressure regulator question:
I really don't think there is something like a electronic fuel pressure controller on the GZE. Think about it: why would toyota bother tinkering with the fuel pressure, when they could more easily adjust the ECU for under boost conditions?\
I think I know what your friend was referring to. A fuel pressure regulator always adjusts fuel pressure such that the pressure at the injector is a constant value over the pressure at the injector outlet (intake runner). That means that the injector always injects the same amount of fuel given a fixed time period. Lots of people think that it raises pressure at WOT, but that is not the case! In NA engines WOT means high intake vacuum and thus low fuel pressure. It lowers the pressure!
FI engines run boost (=positive pressure) at WOT, so the regulator then raises the fuel pressure so that the pressure difference stays the same.

The pressure regulator could be made electronic, but i have yet to see one on a engine. The old scool regulators work plenty good and are still widely used. You could check this easily, just look at the fuel rail and pressure regulator (should be at the end of the rail). Any wires going in there means something fishy is going on.

@filh: Please don't change anything without measuring first!!!!! The std lambda probe is more than good enough for this. They are excellent at detecting the lean condition that could be the source of the problem you describe. I think your AE86 should already have one, so just hook it up to a cheap lambdadisplay. Ignore al of the figures where it says what lambda is at. All the std sensor is is a switch that switches over at lambda = 1. Thats exactly what you want to know.