HKS FCD running lean?

I've just read a couple of threads on the forum saying to stay clear of the HKS FCD, as it can make the car run lean. I fitted one of these and since going BPU the AFR implies it's running lean. Can anyone confirm whether the HKS FCD is rubbish and should be replaced?

I believe it scales the signal from the MAP sensor, rather than leaving it untouched but clamping it just below 1v. So yes, it's bad

has any found the turbosmart fcd do the same?

thanks so to protect my engine I should get a different one? which is the best still available?

Greedy

get aopiggyback john. you can clamp the signal and have your fulling and timeing tweeked to find a few more horses

Greedy

Thats not very nice!

I have the HKS FCD fitted on mine and after reading this im wondering what are the other options out there. Just had a quick look on the Whifbitz website, and Turbosmart make two versions ( Manual/Electronic ) and was wondering if this is a better choice??? Anyone got one fitted of any opinions on it? What else is there?

I think the lean thing comes from the transition when turbo no2 comes online. Generally JZs are generously overfuelled.

Is the Thor fcd the same? Still not fitted it, but I've heard good things about it.

The Thor one is supposed to be good, Thor themselves recommended the Greddy one to me when I enquired with them, they don't do their own anymore I dont think?

get aopiggyback john. you can clamp the signal and have your fulling and timeing tweeked to find a few more horses

was thinking the same, any suggestions? Not intending to go single, so just to maximse bpu.

I have been playing on and off over the past few months with a bit of circuitry of my own to try and achieve something a bit closer to what I felt was needed. Basically it relies on the map sensor voltage to do what it should up to the point moments before fuel cut and then clamps it at that and then when the boost level gets to about 1.15bar it then re-instates fuel cut. The problem is that from what I have read and seen with Ian's and Andy's published data the output from the stock map sensor is a bit unreliable at the higher boost levels, but on mine it does seem to work ok at 1.15. I also messed with a 2 bar sensor from a cossie and I relied on the supra map sensor for the pre cut level which then clamped and then when the ford sensor saw 1.2 the circuit then went into cut. But this is a messy way of doing things imo.

I was also thinking about this the other day, as an SAFC will bassically fudges the map signal, then I would think that you could use one for a FCD too, but havent tried this.

I supply a voltage clamping device that works fine, but it has NO safety fuel cut. Cheap, works fine, but you need to be sure that you are confident of wastegate plumbing.

TRD one is no longer made, Greddy one works fine, but sometimes hard to get. HKS one apparently has issues but I don't use them.

was thinking the same, any suggestions? Not intending to go single, so just to maximse bpu.

E-Manage Blue, but it's overkill just for dodging fuel cut. It'd be way better for BPU, but then it's a step up from £100 to north of £500 once you've got the unit, the harnesses, the MAP sensor, installed it, maybe a field harness to make the wiring-up better, and then getting it mapped. It also doesn't reinstate fuel cut, but you can map it to pull timing and dump in fuel if the boost gets too high. The driver should then realise something is wrong as performance would suddenly and radically change.

We have fitted hundreds of HKS FCD's over the years and never had an issue with them. The Supra still runs rich with the HKS FCD fitted so really no need to change at all.

We have fitted hundreds of HKS FCD's over the years and never had an issue with them. The Supra still runs rich with the HKS FCD fitted so really no need to change at all.

AFR reading is 12.3 on full boost which is on the lean side from what I've read. As I track the car I would rather it be on the slightly rich side.

AFR reading is 12.3 on full boost which is on the lean side from what I've read. As I track the car I would rather it be on the slightly rich side.

That is a tad lean, are you sure its not something else causing it as I've never seen an HKS FCD do that before.

I have had plenty of cars here with the HKS ones already fitted, and not seen any trend for them to run any weaker than with any other FCD. Is the Greddy one still freely available, I thought someone said it was being discontinued?

The Greddy BCC is no longer available yes. Turbosmart FCD seems to be very good though, http://www.turbosmartonline.com/index.php?s=fuel-cut-defenders

I put a new walbro in, new AFR gauge and recalibrated it a few times to check. Fuel filter's only about 5000 miles old. Everything else would be stock fueling wise.

The HKS one scaling the whole signal must have been old skool myth and lore then If people have experience of them working fine, then I'd take their word on it.

I have never tested their output, to be honest until quite recently my knowledge and interest in electronics was near zero, but I am pulling myself, kicking and screaming, into the digital age

I have a j-spec supra 2jzgte, and i have mountet the hks fcd, i also have the problem with the car running lean, i have mountet is after this guide:

http://www.mkivsupra.net/vbb/showthread.php?251053-HKS-FCD-Installation-Instructions

under idle the air/fuel gauge reads 14.8 to 15.2 witch is pretty normal..

under load the car leans total out. 17 to 18 on the air/fuel gauge...

does the hks FDC not Work on a map based car, or what am i doing wrong

I have a j-spec supra 2jzgte, and i have mountet the hks fcd, i also have the problem with the car running lean, i have mountet is after this guide:

 

http://www.mkivsupra.net/vbb/showthread.php?251053-HKS-FCD-Installation-Instructions

 

under idle the air/fuel gauge reads 14.8 to 15.2 witch is pretty normal..

 

under load the car leans total out. 17 to 18 on the air/fuel gauge...

 

does the hks FDC not Work on a map based car, or what am i doing wrong

Is yours a VVTi or pre-VVTi?