HKS Fuel Cut Defender Problems

[suprra_girl]

I would never run over $80 but that's up to you.

I use it, my fc is at aboutttttt 10psi which his about 16psi on the 46trim ct. So i still have my safety net I've just gotta get it moved some more hehe. I'm running very rich so a little tuning needed

 

[MRSUPRA]

"The FCD is just not worth the risk. Especially if you dont no what your doing."

And if you don't no what you're doing, you should only be doing exhaust and intake mods.

 

[NewGen]

lol agreed

 

[tekdeus]

Do you even know how an FCD works? It's fixed frequency signal clamp. Meaning that once your AFM reaches a certain level, it "clamps" the signal there and fails to report the greater airflow to the ECU. As your airflow increases, the fuel does not and the car gets leaner and leaner. This is about as far from "exact" as you can get. The Reimer upgrade is damned close, and within the learning capabilities of the ECU. The FCD is exact in one way. It's exactly the perfect way to blow an engine with too much boost.It's the absolute worst case scenario, and your statements are dangerously ignorant.

I hit fuel cut for the first time the other day when it was cold out, 18psi, after finally replacing my high-flow cat with a test pipe, running a 57Trim CT, Lex AFM, 550's at 50psi, SAFC, and monitoring with a wideband tuned to 11.5 at WOT. I will first check for boost leaks, but if I still get fuel cut, especially if I upgrade the turbo, can I safely use the FCD to lock the AFM signal, but add in fuel with the SAFC and monitor/datalog with my wideband?

What other problem besides a boost leak could trigger fuel cut with my setup?

 

[suprra_girl]

Yep you should be able to do that with the safc, that's what i'm going to do coz fuel cut is a major pita. I can't sit on 14psi for more than 2 or so secs and it hits :/ damn stock ecu lol.

The only thing to watch is when you pull fuel with the safc it will advance timing a wee bit so other than watching it on the dyno i'm not sure how else you can monitor it. As long as you don't go stupid with pulling fuel I would assume it would be alright as long as you're using good fuel too.

edit: I'm using a fcd as well!!! My ecu just hates on my air volume If you already have an safc do it, or just wind the boost down a bit and save up for a standalone. Thats what i'm doing

edit 2: Also if i recall the type K does not clamp the signal it merely moves it. Map sensored cars with hks fcd's clamp the signal entirely.

edit 3: Clearly i'm not very good at reading LOL. If you add fuel (in actual fact you are just adding air signal) you will actually make it worse. To move fuel cut up you need to lessen the air signal, how I was going to achieve this was raising fuel pressure to 45psi then taking out fuel with the safc

 

[IJ.]

^ Look what the cat dragged in

 

[Poodles]

FCD was meant to be used with the full electronics suite from HKS, not alone... And in that case tuning IS REQUIRED because you can still blow up the car. Funny thing is that it was a bunch of piggybacks that made it almost function like a standalone, when today standalones are far cheaper.

IJ will agree that standalones are the way to go instead of using multiple piggybacks and blowing stuff up...

 

[tekdeus]

Yep you should be able to do that with the safc, that's what i'm going to do coz fuel cut is a major pita. I can't sit on 14psi for more than 2 or so secs and it hits :/ damn stock ecu lol.

The only thing to watch is when you pull fuel with the safc it will advance timing a wee bit so other than watching it on the dyno i'm not sure how else you can monitor it. As long as you don't go stupid with pulling fuel I would assume it would be alright as long as you're using good fuel too.

edit: I'm using a fcd as well!!! My ecu just hates on my air volume If you already have an safc do it, or just wind the boost down a bit and save up for a standalone. Thats what i'm doing

edit 2: Also if i recall the type K does not clamp the signal it merely moves it. Map sensored cars with hks fcd's clamp the signal entirely.

edit 3: Clearly i'm not very good at reading LOL. If you add fuel (in actual fact you are just adding air signal) you will actually make it worse. To move fuel cut up you need to lessen the air signal, how I was going to achieve this was raising fuel pressure to 45psi then taking out fuel with the safc

The FCD moves the signal? In what way? My FPR is already set to 50psi base pressure, and I have dual walbros, so I have tons of fuel. Am I really maxing out 550's on this little 57trim turbo???

 

[suprra_girl]

^ Look what the cat dragged in

Hehe, well, as you so well named it, I've become quite knowledgeable in the alphabet soup so I thought i'd stick my ore in

FCD was meant to be used with the full electronics suite from HKS, not alone... And in that case tuning IS REQUIRED because you can still blow up the car. Funny thing is that it was a bunch of piggybacks that made it almost function like a standalone, when today standalones are far cheaper.

IJ will agree that standalones are the way to go instead of using multiple piggybacks and blowing stuff up...

Agreed, standalone at the end of the day is much better. If you already have the safc then i'd tune it a bit.

The FCD moves the signal? In what way? My FPR is already set to 50psi base pressure, and I have dual walbros, so I have tons of fuel. Am I really maxing out 550's on this little 57trim turbo???

Well, with the fcd on my car, previously I could only boost 5-7psi depending on weather hitting fuel cut, with the fcd in I could then run 10-12psi but if it was cold I would still hit fuel cut. That tells me it only moves it.

I'm not sure why you are running 50psi, mine when idling is 35psi and I run 14psi (hitting fuel cut haha, My fuel is easily 10's when wot so I don't tend to full boost it much till I get it tuned)

I would have thought having 2 walbros and 550's you wouldn't need anywhere near that pressure. Admittedly i'm not using the lexus afm, I have the fcon with 550 chip.

How did you go with boost leak checking?
You have a wideband on board don't you, how is the fuel when idling and throttling lightly, stoich or rich?

 

[suprra_girl]

Just reading your first post again, it seems you have unrestricted the exhaust slightly so that could be your issue. I used to run 10psi happily till I did my exhaust system, thats when it dropped to 6-7psi being all I could run (had to remove my boost controller) and fcd for the win! I could run 9psi at 11.7:1 Altho then I was still on the stock fuel system, I'm sure if I put in 550's and fpr and the fcon I could have run some more silly boost (on my 46trim) but I think I would probably still have some fuel cut issues.

At the end of the day, If like me and you already have an safc then pull some signal out with it and that will raise fuel cut a little. How much by I'm not sure as I haven't done it yet. If you don't have an safc already, lay off the wot on cold nights and save up for a standalone as at the same time you get rid of that inconvenient strand you on the side of the road to fix a boost leak AFM.

Altho, i'll tell you, i didn't just buy a fcd and stick it on and go mad. I wired it in and drove normally to the dyno and ensured my fuel was aok wot before I went nuts

 

[tekdeus]

How did you go with boost leak checking?
You have a wideband on board don't you, how is the fuel when idling and throttling lightly, stoich or rich?

Been waiting on a gasket to bolt her back up to check for boost leaks. My wideband shows idle and light throttle to be stoich, and it runs great. It's just that my 57trim is smoking and has major shaft play. I'm probably going to put a turbo on that will have me hitting fuel cut every time, so I'm trying to see if I can work around it for now. How about bigger injectors, and letting unmetered air in after the AFM? Can I tune this reliably?

Not sure how the FCD can move the fuel cut point, if it's just limiting the signals that go above 5v??

 

[suprra_girl]

It's not a volt system, it's HZ, thats the karman signal. It somehow screws with it. I'n not sure if it picks a frequency range specifically or how it selects it.

I do know the original hks type k (steel box type) raised fuel cut ALOT possibly even clamped it completely as I remember getting to 25psi odd accidently once and I didn't cut. Lucky I was watching and it caused no damage as I backed off immediately.
The newer plastic ones with the dial I find as fcd's are quite pathetic. I mean c'mon, I gain a whole 3-4 psi (admittedly on different turbos flowing different volumes) but I thought i'd get more than that.

I'd say if it's stoich then I'd say possibly boost leak free. How much of a restriction is that pipe you took off? It could be that it was just uber cold that night... I'd try again.
You know you want to hehe

 

[Poodles]

A boost leak in the form of a leak at a coupler wouldn't show itself until under boost (unless it was compeletly disconnected).

Letting in unmetered air after the AFM actually HAS been done. One of the local guys bought a car with an extra throttle body with a boost solenoid to open it. Was extremely rigged, but made over 500HP. He disconnected it though and ran low boost becuase it was too risky.

 

[suprra_girl]

That's true, you have a point there, I had a small leak at my turbo coupler back when I had my 6-7psi issues, only with the leak I was getting 5 till I hit fuel cut LOL

That is my main goal once I tune out fuel cut a little, getting rid of the damn afm!!!


edit: Oh and before you say it Ian, it won't be with more alphabet soup like a vpc, it'll be standalone haha

 

[figgie]

The FCD moves the signal? In what way? My FPR is already set to 50psi base pressure, and I have dual walbros, so I have tons of fuel. Am I really maxing out 550's on this little 57trim turbo???

***I swear, is reading comp even a requirement anymore in school in North America???***

This has been known for quite some time. As Mike (Supracentral), repeated by suprra_girl and now I am repeating again (and damn it, I really really hate repeating myself or someone else!!).

Do you even know how an FCD works? It's fixed frequency signal clamp. Meaning that once your AFM reaches a certain level, it "clamps" the signal there and fails to report the greater airflow to the ECU. As your airflow increases, the fuel does not and the car gets leaner and leaner. This is about as far from "exact" as you can get. The Reimer upgrade is damned close, and within the learning capabilities of the ECU. The FCD is exact in one way. It's exactly the perfect way to blow an engine with too much boost.

It's the absolute worst case scenario, and your statements are dangerously ignorant.

More specifically the clamp is somewhere in the neighborhood of 1400hz (±15%) dependeing on a couple of factors. The FCD makes sure that the Hz never goes above that "magic" number meaning that the motor can injest more air but it will be telling the computer that it is still just seeing 1400hz meaning a lean situation will quickly arise.

 

[Poodles]

And how that worked is that the rest of the HKS piggybacks where tunable even if it's locked at that level.

FCD was NEVER meant to be used alone...

 

[figgie]

And how that worked is that the rest of the HKS piggybacks where tunable even if it's locked at that level.

FCD was NEVER meant to be used alone...

Tuneable within the confines of the TCCS. The HKS chock full of piggy backs never had direct control of the injection or ignition so it was still lieing to the TCCS to get what it wanted.

 

[Supracentral]

http://www.supramania.com/forums/showpost.php?p=941048&postcount=16

'nuff said.

 

[tekdeus]

I've gotten 622 RWHP from a Lexus AFM, 850cc injectors and an APEXi S-AFC running on C-16. I have NEVER used a FCD in any 7M powered Supra. They are, in my opinion, dangerous and unnecessary with these cars. That was almost 10 years ago.

With Will Neelys car we hit 733 with a the VPC & S-AFC combo. A good number of "big power" Supras got worked on in my driveway.

How did you get so much air through the Lex AFM for 622RWHP without fuel cut? Bypassing it somehow?

 

[Supracentral]

How did you get so much air through the Lex AFM for 622RWHP without fuel cut? Bypassing it somehow?

Tuning. That was Eric Varah's car. That's a "ragged edge" dyno tune with one serious built motor underneath it running some serious fuel.

The point is, we have NEVER used FCD's. Fuel cut is to the fuel system what a rev limiter is to ignition. Removing it completely is a recipe for disaster.

It's a cheap ass, dumb ass way to get around a perceived problem, that isn't really a problem at all, it's your ECU trying to save your motor.