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The mkiv Supra Owners Club

HKS FCD running lean?


downimpact

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This thread seems to be going round in circles.

 

What is it you actually want to do with the car? If you are simply looking to go BPU then you dont need to scale the voltage at all, and as you have been told a few times already, this is a bad thing. All you need to do it to clamp the voltage at just below the fuel cut point, leave it well alone until then.

 

But, maybe I am missing what it is you are trying to achieve, if so try to explain.

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i will only raise my boost to 1.2 bar.. but i get fuel cut when i go over 1.0 bar off boost.. and now i been told that the hks fcd scale the voltage to the ecu, and the car then run lean.. so i what to find a safe way the remove the fuel cut on my car.. and thats way i wantet to now about the turbosmart fcd2 does it scale the voltage to the ecu like the hks does, or does it follow the map sensor voltage to 4.40v and then hold the output voltage on 4.40v so i dont get fuel cut and the car dont run lean??

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i will only raise my boost to 1.2 bar.. but i get fuel cut when i go over 1.0 bar off boost.. and now i been told that the hks fcd scale the voltage to the ecu, and the car then run lean.. so i what to find a safe way the remove the fuel cut on my car.. and thats way i wantet to now about the turbosmart fcd2 does it scale the voltage to the ecu like the hks does, or does it follow the map sensor voltage to 4.40v and then hold the output voltage on 4.40v so i dont get fuel cut and the car dont run lean??

 

If the Turbosmart doesn't operate in the way you suggest, then you do not want it. The only way of knowing this 100% is to run a test on it.

 

I have not heard of any cars running lean at 1.2bar if the clamp is applied a fraction before fuel cut. So as long as everything else is ok with your set up you will be fine clamping it at that point.

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If the Turbosmart doesn't operate in the way you suggest, then you do not want it. The only way of knowing this 100% is to run a test on it.

 

I have not heard of any cars running lean at 1.2bar if the clamp is applied a fraction before fuel cut. So as long as everything else is ok with your set up you will be fine clamping it at that point.

 

 

that i way i am asking as i dont now. i dont what to buy something Again if is does the same as the hks fcd do..

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If you don't want to buy one and test it to confirm, then contact this guy http://myworld.ebay.co.uk/gttidevelopments/&_trksid=p3984.m1439.l2754 He will make you one which will perform perfectly, but it will totally remove your fuel cut. You will be pleasantly surprised at the price too. The stock MAP sensor output will remain unchanged until the fuel cut point, there is a single multi turn pot for you to set the exact clamp point.

Edited by Shane (see edit history)
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as i can see out from this, is that it Work like the greddy bcc, it forllow the stock map sensor signal, to a set voltage ex 4.1v and then holds it there.. and you can also have an extra safty by having a higere boostcut where the fcd2 relese the voltage ex 4.40v if car car someday overboost... is that understud correct?

fcd.png

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as i can see out from this, is that it Work like the greddy bcc, it forllow the stock map sensor signal, to a set voltage ex 4.1v and then holds it there.. and you can also have an extra safty by having a higere boostcut where the fcd2 relese the voltage ex 4.40v if car car someday overboost... is that understud correct?

 

Well if it does that, then what's the issue?

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  • 1 year later...

I am reviving this old thread as I am now doing my own FCD. I had a MKIV in today for a lean run condition. I was told this started when a de cat, a fuel pump upgrade and a free flow exhaust was fitted. At the same time a brand new HKS FCD was fitted.

 

 

I got my pal to fit my wide band to it and sure enough the fuelling was all over the place. To cut to the chase I removed the FCD from it and the engine ran fine with no mixture issues, but it then hit fuel cut.

 

Tonight I decided to test the HKS FCD on the bench, properly and I am unsure if it's faulty or if they are all a lot more suspect than I thought. My standard test is to run an FCD on 13.8V off one bench supply, on the red / black wires to mimic a running system voltage. I then used a separate lab power supply to go 0 to 5V on the wire that would come from the MAP sensor to the FCD, whilst monitoring what comes out of the other wire to the ECU. Not only did it skew all voltages far more than I had believed they normally did, but lets say you turned the dial switch for clamping at as near 3.5V as a position allowed, with 5V into it. If you lower the 5V in to say 4V the 3.5V out should remain at the same clamped level. It doesn't not by a long way. The whole thing was just bizarre. I want to get hold of a new one, or another one to test. In the meantime has anyone got one and an accurate multi meter and a metered variable power supply to test it with? It looks a legit HKS one, but there is so much copied junk out of China these days, who knows? I had a clone boost controller give shocking problems on a Skyline the other month. Looked 100% until you realized some of the menus were missing, and inside the PCB was missing a load of components! An Ebay buy for about 25% less than the real McCoy from a proper Trust reseller. 75% of the price a real one wasted, plus a lot of diagnostic time to pay for. Bargain..... ;)

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The only time we've seen these fail is when they've been fitting incorrectly, we had a Supra in a few week ago for instance and it was wired up all back to front, we wired it up correctly and the car ran lean.

Fitted a new one and it was fine, so the whole cause could be fitting them incorrectly damaging the units.

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This may well be a faulty unit, as I have said in the past I have used them since the Greddy one became obsolete, with no obvious problems. They certainly didn't make the engine run badly like this one, although the fact they skew the MAP sensor output is very poor and seemingly common knowledge. But HKS acquired a powerful marketing position when the Greddy one was discontinued. I am curious to get hold of a brand new one and test it properly.

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I have the hks fcd fitted for the last 8 years..the car is running 1.2 bar..took it on the dyno a few weeks ago (see post running lean on jspec bpu) and on wot the afr was 14...could this be a problem? What can i.do? Thought of flow testing injectors change fuel filter and check the.exhaust for any leakage first..never thought of fcd beeing the problem

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Do what I described above, see if the output follows the input exactly until the clamp volatage is reaced. Happy to test one if you want to post it over, just cover return postage. I'd do a YouTube video if A: I had a suitable camera, and B: I had the slightest clue how to make a YouTube video ;)

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When are you going to start selling yours?i will check some other stuff first and if it keeps running lean i might change it with one of yours..strange thing is that is been fitted on the car for the past 8 years and run good..this.is the first time i checked the afr and showed 14 on wot...we will see..is it.easy to replace the hks.with yours?

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I am building more tomorrow, and I will have stock by the evening. They are a straight swap. For simplicity I decided to use the same colour wires as used on the discontinued Greddy units, red, black, white and green. I could then utilize the umpteen on line illustrated fitting instructions people more skilled with a camera had already created ;)

 

Here's a good example:

 

 

http://mkiv.com/techarticles/bcc/bcc_install/bcc.htm

 

 

 

 

The colours, apart from the red and black, differ on the HKS, but of the other two one goes straight to the ecu, the other to the engine loom, just take note as you remove the HKS. If you prefer to know the HKS colours I can easily check and give detailed info. Very easy to swap them, very easy indeed.

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