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HKS FCD running lean?


downimpact

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2.65v is the correct voltage to see on pin 62, it's atmospheric pressure :)

 

Where did you get these test values from?

 

Having read through the rest of this thread again, I'd say your best course of action right now is to remove the HKS FCD from the MAP sensor wire, reconnect the two ends, and give it a test drive. Using the accelerator to control boost as best you can, check the fuelling at atmospheric, just below 1bar of boost, and a couple of places in between.

 

Once you've got this baseline, you can reinstall the HKS FCD and do these tests again, see if it changes anything but full boost. If the fuelling changes at atmospheric, it's scaling the entire signal and should be thrown out.

Edited by Ian C (see edit history)
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it got the info from supraforums.com..

 

i have taken contakt to the seller off the hks, and he will send me a replacment hks fcd.. but i really need some WHO have the fcd, at messure the voltage output from 1 - 12 on the adjustment.. so i have something to compare with mine..

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it got the info from supraforums.com..

 

i have taken contakt to the seller off the hks, and he will send me a replacment hks fcd.. but i really need some WHO have the fcd, at messure the voltage output from 1 - 12 on the adjustment.. so i have something to compare with mine..

 

The voltage output will depend on the voltage input no matter which setting you choose. If you measure your voltage output I can tell you if it's correct or not, you don't need someone else with one of these to know that. It should pass the voltage signal through without changing it until it gets somewhere above 4v, and then it should clamp it. The setting 1 to 12 should adjust what voltage it clamps at. The important thing is that the unit doesn't affect the voltage below this setting.

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The voltage output will depend on the voltage input no matter which setting you choose. If you measure your voltage output I can tell you if it's correct or not, you don't need someone else with one of these to know that. It should pass the voltage signal through without changing it until it gets somewhere above 4v, and then it should clamp it. The setting 1 to 12 should adjust what voltage it clamps at. The important thing is that the unit doesn't affect the voltage below this setting.

 

 

This is 100% correct imo too. If the device does changes anything that goes into it up to the point of fuel cut then chuck it and this too is the point I made in the post to TimMr2. If the HKS messes with what it's seeing before the fuel cut point then it's a poor design and for the supra at least running stock ecu and stock MAP sensor then don't use it as there is no need whatsoever to mess with the map. Not until the moment of fuel cut when it should clamp and hold constant. IMO anyway.

 

If you can use a multimeter and something to provide the map sensor with a bit of pressure you should be easily able to make comparisons to what's going in and what's coming out of the fcd. you should then be able to make your adjustments and see the clamping range of the device by changing the settings.

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  • 2 weeks later...

i have now bought some tools so i can test the fcd on the car without running the engine.. i have bought a vacum/pressure pump, so i can get some input voltage to the hks fcd on different boost range,

 

my test range will be from 0.8 (vacum) - to 1.2 bar (pressure).

 

the White wire will be connectet to the wire there goes to the map sensor, and the yellow wire will be connectet to my multimeter so i can messure the output voltage from the hks fcd..

 

but do somebody now what numbers i should get from the hks fcd output (yellow wire) in this test range/area

 

vacum range area:

 

0.8 ->

 

0.7 ->

 

0.6 ->

 

0.5 ->

 

0.4 ->

 

0.3 ->

 

0.2 ->

 

0.1 ->

 

0.0 ->

 

pressure test area

 

0.1 ->

 

0.2 ->

 

0.3 ->

 

0.4 ->

 

0.5 ->

 

0.6 ->

 

0.7 ->

 

0.8 ->

 

0.9 ->

 

1.0 ->

 

1.1 ->

 

1.2 ->

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going to be very interested to see what results come up from this.

 

I've heard from looking on the net that people are also saying that when moving from a HKS FCD on stock ecu to just standalone ecu replacement the car feels alot smoother, Turbo transition is also very smooth and compared it to being jerky before.

 

This would make sense as to be honest my supra does feel a little "unrefined" is the best work, feels like a rough map, 2nd turbo engagement isn't really smooth, its like there is a hesitation on transition before the 2nd big kick etc.

 

Hopefully in a few weeks I'm going to get my power fc mapped, so this will give me a few indicators on how the HKS FCD is effecting the overall drivability of the car.

 

Tim

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A decent wide band should show what the HKS FCD is doing, if anything, prior to boost cut. Personally I think anyone modding a turbo engine should make a good wideband their first purchase, along with a high quality mechanical boost gauge, if they decide to fiddle with boost control in any way at all. I have to say I have fitted a lot of HKS FCD's since I was unable to get any more Greddy ones, and haven't noticed any real issues with them.

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See alot of people are claiming they are seeing issues, and some posts I've seen on the USA supra forums are claiming changes in drivability (improvement) when going from HKS to a Greddy unit.

 

I agree a wideband is good to see, but you also need a base reading from each pressure point as reference. Because no point having a wideband and seeing 11.0:1 and just thinking, well its working all ok, AFR's are find so must not be doing anything. Where it might actually be 10.0:1 before the HKS was fitted. See my point.

 

Where the tests JZA800 is doing you'll be able to see exactly what is going on.

 

The way i would personally do it is with his Vacuum/pressure tester go from 0.8vac to 1.2boost and have 2 multimeters. One on the output of the Map sensor (pre FCD) and then another on the outlet of the FCD.

 

By doing this you can see what actual changes are going on in voltage form. So 0 on the gauge (atmospheric) I'm estimating should be around 2.0volt, So if you start seeing 1.8volt coming out the FCD you know its having an altering effect across the entire map, so this would then effectively give less fuel and increased ignition advance across the whole map. If until say 1bar you are seeing the same MAP out and FCD out, you know its working as a voltage clamping device instead.

 

Tim

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Not many people on here will have an accurate metered vacuum and pressure pump, and one or two multimeters (Tim's 2 multimeter test is an excellent idea, I like that). The ones who might have are probably traders and do this sort of thing for a living, so they probably expect to be paid to use their equipment, time and expertise. It's not exactly a 2 minute job ;)

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got damm, im very happy with the advise about cheking the fuel flter, it was almost closed off dirt, so put in a new fuel filter, now i get afr at 10.8 at rpmlimit (6800 rpm), that was much better than afr 11.8 at redline (6800 rpm).. so now i will trye to put the hks fcd on the car Again and see if that change something..

 

so my pryer to you guyes CHANGE YOURES FUEL FILTER ;)

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I always stick a mechanical fuel pressure guage in cars with EFI, you can see at a glance if you have surge, or a fuel pressure problem. For safety you should put an isolator membrane between the high pressure fuel line and the guage, near the pressure take off tapping point so if the line bursts inside the car (accident, abrasion, or fire) the fuel can't be spraying at you, alight, at 50 PSI ;). Mechanical gauges usually respond faster than electrical ones and unless you spend a LOT on high end electrical gauges, mechanical ones are more reliable. Put one in even if it's temporary until everything is proven AOK. Blank the pipe off and coil it up out of the way when done, for easy future problem tracing. Those diddly little things on the FPR, under the bonnet are no damn use at all, unless you are on a rolling road and bent inside the bonnet with the thing on full waft about to spit a rod..... err, no thanks!

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i have now done some tests on the fcd.

 

fcd 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

 

 

 

thats the numbers i got by testing the fcd on the car, whitout connecting the yellow to the ecu. the car was not running, i have bourgt a handpump and connectet to the map sensor... so somebody WHO can help me further to the right number on the fcd...

Edited by jza800 (see edit history)
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