From reading the instructions each car has a different channel the FCD needs to be on in order to work right. Well the manual didn't have any info for mazdas. Does anyone know the correct channel to set it on? I have it cranked all the way, could this cause problems? The car backfires real bad at 6K in 3rd gear, it wont go past it.

How many psi are you running? Any fuel mods?

hks has a bunch of different fcd's are you running the right one?

87 with S5 block and turbo with ported wastegate. I'm running 10-12 psi the the fcd came with the hks-fcon, right now I have the f-con set on 4. I have a walbro pump. Those are my fuel mods and I have full 3" intake and exhaust. The car is damn fast. I drive it like once a week now. I took my car to an automatic car was on thanksgiving and it hasn't driven right since. The exhaust is quieter and it doesn't boost as fast as it use to. It will hit 12 psi by 3K but wont pull like it use to. If I don't boost I can go through all gears to redline, very slowly though. Even last night it was weird, I still cant go past 6k in 3rd gear and it will blow like 6 fast flames out the exhaust. When I first got the car if I floored in in second gear without boosting it in first gear, the car would jump a car length in a second. It went from running 13s to 14s. I haven't got around to checking the compression yet, was 110, but I don't want the car running hitting fuel cut if that's what the 6k problem is. Most the time driving though I keep it at 6-8 psi. I don't really race it that often. When I do I want it to perform though. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

no one's running an hks f-con?

If your pushing those boost numbers it can't be fuel cut. Fuel cut s/b @ 8.6psi.



I don't run an fcon, but do have a little bit of experience with FCDs. When I built one I had to adjust the clamping voltage down a shade from the recommended starting point. I assume the knob on the hks fcd is just for minor adjustments to the clamping voltage. Every car is a little bit different so you need the flexibility.



I've only run into fuel cut twice, and in my experience it was extremely severe. It's hard to communicate this kind of stuff over the internet, but what you are describing does sound sort of like fuel cut. I just don't see how at those boost levels.



Hmm, good question.

i am, but mines from a supra, and thus i couldnt use the hks fcd because the supra fcd works differently.



the fcon units are the same, so i bought the fc chip and harness and it works