remove stock fuel cut on j-spec 2jzgte

[Ian C]

We've done this already, I'm sure of it. Scott M is correct in these matters. At some point you'll have to bite the bullet and actually get an FCD and wire it in. Get the Turbosmart one, we've already said several times it'll work properly. Until then, this thread gets hoofed out of tech.

[bignum]

i`m hitting 1.6 bar here, whats going on:eyebrows:

[jza800]

They are only £350 ish second hand.

 

i only found one on ebay to £536.49

[jza800]

We've done this already, I'm sure of it. Scott M is correct in these matters. At some point you'll have to bite the bullet and actually get an FCD and wire it in. Get the Turbosmart one, we've already said several times it'll work properly. Until then, this thread gets hoofed out of tech.

 

i allredy bourgt a fcd. from hks.. and as it dont Work probely, i wantet to be sure to get the right one this time, instead off just buying something tht might not Work..

[Scott]

i allredy bourgt a fcd. from hks.. and as it dont Work probely, i wantet to be sure to get the right one this time, instead off just buying something tht might not Work..

 

"it don't Work probely" because it's not installed properly IMO.

 

Did you install it? Did you have someone competent do the work? Did they use a multimeter to setup the voltage cap output?

 

It's not rocket science, it takes a bit of patience and some logic to install devices like these. Blind faith won't get you there unfortunately, whether it's in yourself or someone who instils it in you.

[jza800]

it was indstalled correct..

 

Black : grund

 

red : 12v positiv

 

yellow : to ecu pin 62 (cut wire)

 

White : to the wire going to the map sensor

 

yes we had a multimeter on the yellow one, as that is what the ecu see.

[Scott]

And what was the output when on WOT?

[jza800]

on setting 9 and 18 psi. 3.90v stock voltage on 18 psi is 4.91v

[Scott]

Just FYI, I don't actually know exactly how an FCD works. However, here is my logic for your setup not working.....

 

Above a certain pressure the ECU just lets the injectors loose. This is the reason that the TTs are so safe at even the upper BPU levels. It's very unlikely for them to run lean when in and around the 400hp mark.

 

Below that certain pressure the ECU dictates how much fuel goes in there.

 

To much above that certain pressure brings in fuel cut where the ECU just kills the fuel till the boost lowers (head off windscreen)

 

The FCD fits in the middle. Set correctly it sits in the band between injectors fully open and fuel cut.

 

If the FCD is set to cap the frequency too high then fuel cut will still kick in - Obvious

If the FCD is set to cap the frequency just right the ECU will see a pressure above the limit that it opens up the injectors, yet below the point where it hits fuel cut - Sweet spot

If the FCD is set to cap the frequency too low then the ECU will see too low a pressure and will give fuel based on that pressure. As that pressure is "fake", it'll run lean. - Where I believe you currently sit.

 

This is theoretical but simply based on the fact that you have totally written off that we have told you. You are too quick to discount facts, opinions and advice based on nothing more than one particular avenue/post/product doesn't agree.

[jza800]

here are the readings we got

 

----------------9 --- 10 --- 11 --- 12 -- stock

 

 

+18-19 psi 3.90v 4.09v 4.27v 4.45v 4.91v

 

+ 15 psi ---3,59v 3,75v 3,91v 4,06v 4,43v

 

+ 10 psi -- 3,16v 3,31v 3,42v 3,53v 3,80v

 

+ 5 psi --- 2,75v 2,83v 2,91v 3,00v 3,21v

 

0 psi ------ 2,35v 2,40v 2,45v 2,50v 2,68v

 

-5 psi ----- 2,07v 2,12v 2,16v 2,17v 2,20v

 

-10 psi ---- 1,84v 1,86v 1,87v 1,90v 1,95v

 

-15 psi ---- 1,59v 1,60v 1,61v 1,62v 1,66v

 

-20 psi ---- 1,32v 1,31v 1,32v 1,33v 1,33v

 

-25 psi ---- 1,01v 1,01v 1,01v 1,02v 1,01v

[Scott]

on setting 9 and 18 psi. 3.90v stock voltage on 18 psi is 4.91v

 

It's set wrong then isn't it.... Miles wrong.

 

See post above!

 

Out of curiosity. How were you managing to hit 18PSI without the FCD active?

[jza800]

i was mountet on the car. the only wire that not was connectet was the yellow. because thants was the one thats connect to the multimeter to messure the output voltage from the fcd to the ecu.. i bourgt a handpump with a pressure gauge, connectet to the map sensor.. and as my car is a j-spec all fueling is control by the map sensor, as i dont have maf sensor..

[Scott]

i was mountet on the car. the only wire that not was connectet was the yellow. because thants was the one thats connect to the multimeter to messure the output voltage from the fcd to the ecu.. i bourgt a handpump with a pressure gauge, connectet to the map sensor.. and as my car is a j-spec all fueling is control by the map sensor, as i dont have maf sensor..

 

 

Right well here is my thinking. The Supra hits fuel cut when the ECU sees more than 1.0bar of boost. I'm not sure of the exact levels, as it's been a while since I even looked at anything like this, but I believe the ECU just dumps the fuel at 1.0bar. So with that in mind the sweetspot is either going to be 1.0bar, or very slightly under (to avoid fuel cut).

 

So logically I would want the ECU to see, at the max, 14.5PSI.

 

I'm going from your table now, which you say is your results? I'm going to trust you here and assume that you are being honest and that you haven't just pulled that off another forum. So, with those assumptions in mind, I would want to trim the 1.2bar (17.5psi) to 1.0bar (14.5psi). If the MAP sensor, when functional, gives off 4.43v at this level (it'll be just less than that obviously) then I would set the device to read around 4.4V @ 1.2bar.

 

The best setting in that respect is 11.

 

I would personally try 11, if it hits fuel cut then try 10. Between the 2 I can see no way that a functioning FCD would hit fuel cut.

 

My point though? 9 is the wrong setting for a MKIV Supra based on your information.

[jza800]

you can truly trust my readings, as i self messured the voltage...

 

i have tried to run the car on setting 12. it runs great and fuel cut is gone. the thing i dont like is the air/fuel ration. under wot close to 6800 rpm i see 12.0 on the gauge. which i think is not all good. and other i talk to say under wot it should go Down to 11 to 11.5 on the air/fuel gauge..

 

the other thing i dont like is why would a Company like hks recomand a lower setting that after my test seems not to be right ..

 

because if you see on the stock readings i messured, you can see i how much it goes off Scala from the stock readings when the fcd is mountet , that i really dont like as it is missing fuel there.. and thats why i dont like to use the hks one, and if i read on the others fcd ex. turbosmart fcd2 - gizzmo ms-2 - bccd. thay seems to follow the stock voltage range to the clamping point, instead where the hks fcd seems to scaling the Whole boost range to the clamping point.

 

so thats i why i am leaning to some off the others device.

[Scott]

This is my point bud, this has been my point since my first post. My second point is that you aren't taking anything that anyone is saying onboard. I'm having to retype everything over and over again because you are not taking anything on board.

 

An FCD WILL cause lean situations if configured incorrectly or faulty. I already put that.

 

I'll say it again. The FCD you are using DOES work, it's worked in plenty of cars over the years. It needs to be setup properly and competently. If it's not, or if it's faulty, you will get issues. You're having issues, try and find out what the cause is. Chucking another FCD at your issue isn't the solution or where your focus needs to be.

 

Did you check the AFR on positions 9, 10,11,12? Were there any differences? Given your description there should have been.

 

Oh, as I understand it there are different pre-configurations for the HKS FCDs. There are "Toyota" specific ones and there are "Supra" specific ones. You need to get the "Supra" specific one, otherwise the settings are different IIRC. That's just what a quick search of the forum brought up though, I don't have any experience with trying to contribute to such discussions.

 

Just as a side note, on setting 12 you should still hit fuel cut over 1.1bar

Edited September 13, 2013 by Scott (see edit history)

[jza800]

if i am seeing it correcty, it will first hit fuel cut over 1.3 bar on setting 12 as the voltage first is over 4.3v as the fcd first clamp the voltage at 4.45v witch is at 18-19 psi. but at setting 11 there will be no fuel cut, as the hks fcd clamps the voltage at 4.27v..

 

the car run like shit on setting 9 and 10. it has a lot off missfire. because as i think to Little fuel. and it lean out if you tried to give the car a Little gas 17 ti 18.0 a/r.. and yes i tried with a other one, as i thought the one i got was defekt, but the new one did the same..

 

the one i got is the hks fcd std with number fst-19253 witch should fit supra..

[Scott]

Stock 15 PSI (just over 1.0bar) is 4.43v

Interpolated 14.5psi (1.0bar) will be 4.37v

 

Setting 12 at 18PSI (1.25bar) is 4.45v = fuel cut.

 

However, my point is not the fuel cut or anything to do with that. My point is about the AFR, draw your attention to the AFR when you are hitting above 1.0bar as stock. You will notice that it hits rich, around 11 IIRC. Even with at 1.2bar it sits at 11 in my ownership.... and bare in mind that's my experience with 1.2bar and a "leaned out" Mines ECU. Stock you would probably see high 10s. That's for another discussion though as that's clearly nit picking.

 

So, lets go with methodical logic.

 

Bone Stock - 1.0bar of boost pressure - AFR 10.5-11 (approx guess) - MAP Sensor Output 4.3v (Approx)

FCD in place - 1.2bar of boost pressure - AFR 12 (approx from your description) - Adjusted Voltage 4.4v (Approx)

 

 

From simply that alone you can see there is something wrong. It's a fact that the Jspec ECU dumps the fuel on the 2nd tubby at 1.0bar, it's the entire reason why people can safely boost their cars to those levels without any fueling/timing issues.

 

There is either something wrong with your setup, or something wrong with your car...

 

Injectors dumping = 11 AFR = safe

Injectors NOT dumping = Boost showing below 1.0bar = Actual boost below 1.0bar or signal showing below 1.0bar.

 

You need to get to the root cause of what your issue is bud. If you are sending 4.4v to your ECU then your injectors should be firing at their maximum which would mean a nice safe rich mix.

Edited September 13, 2013 by Scott (see edit history)

[jza800]

i dont think there is something wrong with the car. if i take the fcd out, the car run like normal..

 

as you can see on my numbers, the stock range is fine and after the book.. it is only going wrong when the fcd gets mountet, i have tried to messure the voltage from the mapsensor to the fcd (White wire), and that follow the stock range, but from the fcd to the ecu (yellow wire) it goes wrong. so the only problem i can think off is

 

1: the fcd does not get the total 12v input voltage

2: bad ground

 

i have taken the ground and positive by the ecu pins.

 

i will trye the take some messure off the voltages on the ecu.. if that not it, i am on bare ground Again

[Scott]

Now you're thinking along the right lines

[jza800]

i did now test the voltage on the ecu side.. the problem was not there because that there was 12v.. and after reading seeing what tim mr2 wrote, the HKS isn't a clamping FCD its one that is basically a variable resistor so throws out the entire map. if i'm running 1.2bar it must be lowering the map reading by atleast 0.25bar of boost to compensate. So not only is it not injecting enough fuel for the boost but its also going to be using more ignition advance because of the position in the loadcells. Its just allowing for the overfueling nature of the stock to allow enough fuel not to blow up.

 

But like i've said i'm not a fan of trickery to the ecu in anymore. The clamping type is the lesser or 2 evils. But still not ideal.

 

Tim

 

and after seeing the test i did, it do exactly what he wrote. so i have to find another fcd..

[Scott]

i did now test the voltage on the ecu side.. the problem was not there because that there was 12v.. and after reading seeing what tim mr2 wrote, the HKS isn't a clamping FCD its one that is basically a variable resistor so throws out the entire map. if i'm running 1.2bar it must be lowering the map reading by atleast 0.25bar of boost to compensate. So not only is it not injecting enough fuel for the boost but its also going to be using more ignition advance because of the position in the loadcells. Its just allowing for the overfueling nature of the stock to allow enough fuel not to blow up.

 

But like i've said i'm not a fan of trickery to the ecu in anymore. The clamping type is the lesser or 2 evils. But still not ideal.

 

Tim

 

and after seeing the test i did, it do exactly what he wrote. so i have to find another fcd..

 

 

It's not the brand of FCD. Here we go again.

 

What Tim said is absolutely correct, it does throw off the entire map because it drops the voltage across the whole range rather than just chopping off the upper limit (clamp).

 

However... my point to you is that it's either faulty or set wrong. Reason being is that on setting 12 it should be hitting fuel cut as it's NOT lowering the boost by 0.25bar. According to your very own readings it's above 1.0bar.... which should be hitting fuel cut. The obvious point to make during all this is that at 1.0bar the injectors should be flowing at full pelt = mega rich. It's not hitting fuel cut and it's running lean, ergo it's set wrong, or it's faulty, and your readings are incorrect.

 

All of the above has now been said around 5 times just by myself.

 

However, for the sake of not going around in circles anymore I'll stand by what I said in one of my opening posts. Get a readily available FCD that'll do the job without any setting up etc, post a wanted ad for the one you would like to have in the future (greddy would be my choice) and you're sorted regardless. If the HKS is not faulty, you'll get around £40 for it.

[jza800]

i have a hard time to understand how 2 hks fcd can be faulty. you can see on the test i did, how much i go Down/away from the stock voltage. and as my map sensor control the fuel to the engine, i dont like that i goes so much away from the stock map basic on the range.

 

and as you self wrote it trow the entire map as i drops the voltage, so thats why i dont like the hks fcd. i like to have the safe limit to now that the fcd follows the stock map sensor signal/voltage and just clamps to voltage on 4.3v. around 1 bar. like the greddy Bcc does.. then it will first lean out from 1 bar and up.. instead ex from 0.1 bar...

[Scott]

i have a hard time to understand how 2 hks fcd can be faulty. you can see on the test i did, how much i go Down/away from the stock voltage. and as my map sensor control the fuel to the engine, i dont like that i goes so much away from the stock map basic on the range.

 

and as you self wrote it trow the entire map as i drops the voltage, so thats why i dont like the hks fcd. i like to have the safe limit to now that the fcd follows the stock map sensor signal/voltage and just clamps to voltage on 4.3v. around 1 bar. like the greddy Bcc does.. then it will first lean out from 1 bar and up.. instead ex from 0.1 bar...

 

 

It can only be a handfull of things though.

 

Faulty FCD

Improper fitting/use of FCD

Fault with the car

 

The FCDs are used on numerous TTs on this forum with no hassle. This seems to be eluding you entirely as you seem insistent that you are the only person ever to have tried an HKS FCD.

 

As I said, cut your losses. Get an idiot proof variant to get you going just now and put up a wanted add for a greddy. Job done

 

 

As for the qualities of the FCD. I wouldn't worry so much, when working properly, as the stock map is silly rich anyway. There is loads of headroom for a bit of leaning off through the rev range. It's probably advantageous on a stock TT, power wise, as long as everything is fitted/working correctly.

Edited September 14, 2013 by Scott (see edit history)

[jza800]

It can only be a handfull of things though.

 

Faulty FCD

Improper fitting/use of FCD

Fault with the car

 

The FCDs are used on numerous TTs on this forum with no hassle. This seems to be eluding you entirely as you seem insistent that you are the only person ever to have tried an HKS FCD.

 

As I said, cut your losses. Get an idiot proof variant to get you going just now and put up a wanted add for a greddy. Job done

 

 

As for the qualities of the FCD. I wouldn't worry so much, when working properly, as the stock map is silly rich anyway. There is loads of headroom for a bit of leaning off through the rev range. It's probably advantageous on a stock TT, power wise, as long as everything is fitted/working correctly.

 

hmm than i have to be a faulty fcd again, the fitting i as the instruktion says. if the car was faulty it should do the same with the fcd off. and as the car drives like normal i doubt the car is faulty..