Johnyquest

I just attempted to AFC hack my car, in prep for the turbo that's going in in a few days. I installed the 450's and a resistor box, and clamped the AFC down to -36 to start. I ran the car, and the A/F gauge read RICH RICH RICH. So I kept downing it until now i'm at -50% and it's still rich as all hell. I have a walrbo 255 i installed last week, but it was running ok with the stockers for the week so the FP must not be to high..? Did I miss somthing here? The car is smoking like a bandit and running like ****. HELP!

KingDsi

Do you have a fuel pressure regulator? Your fuel pressure is probably too high. Usually when you put a high flow fuel pump in, it raises your fuel pressure.

Johnyquest

Nah, I don't have an FPR, but it's all good... I figured out my problem. It's a case of idiot syndrome... The AFC has a parameter "sensor type" which needs to be set to #6. I had it the way it was set stock(in #1, out #1), which didn't allow for any adjustment of the a/f ratio cuz the setting wasn't for my car. I fixed it, and it works mint now. I'm about to go out and try and tune it some more. Running I/H/E w/ walbro 255 + dsm 450s! Turbo is going in reallll soon. I think I need to buy radiator fans (pusher) to make room. All I need now is a DP and Charge piping.

Alstare

I didn't know you could even run the AFC hack without the turbo in yet? Wouldn't that be too much fuel without the added boost of air?

T25 civic

well think about it, if -50% limits half the voltage, then the car is basically seeing 50% of the 450 cc's theoretically. So at -50% its only seeing 225cc injectors when our stock injectors are 240cc I beleive.

This is what makes sense to me, but does not mean its 100% acurate. lol
Nick

Johnyquest

Everybody with DSM 450's: I am having SO much trouble getting them to run right. Every time I get it to idle nicely, it hesistates when I try to rev it. It just started blowing black smoke (too rich??) when I rev and popping, so that's my guess. When I lean it out to where it doesn't blow black smoke, my A/F gauge reads blank (which is wayyy lean) at idle. It goes good @ full throttle, but i'm not sure where to tune it to. Should I tune it to run stoich or a little rich (like it used to run with the stockers at full throttle?) Also, how bad is it for the car to be lean at idle? Does lean only damage the motor under load, or all the time? I'm lost.
Any tuning advice would help, I'm having a lot of trouble here!

KingDsi

Which AFC do you have? Does it have a low and high throttle fuel +/-?
If you have just high throttle control then you are going to have a problem with adjusting the fuel control with big injectors. If you have a low throttle control then that's the most important with big injectors. The reason being, is that you need to limit the fuel below full throttle (80%) because with big injectors you would run WAY rich and the computer could not control the fuel. However, when you go into full throttle, your computer goes into open loop and ignores all sensors and has preprogrammed fuel maps and whatever the injectors flow, they will flow based on the pulse (this is why no FMU is needed- also a fuel injector that flows 30cc vs. a 25cc will flow more with the same pulse,the pulse doesn't change with the fuel maps unless you have high throttle control)
You wan't to run a little lean during idle, balance during cruise, and rich during boost.


[Modified by KingDsi, 6:27 PM 12/26/2002]

Johnyquest

I've got the digital SAFC. I'm getting it to work a little at a time : )

Johnyquest

Just wanted to let everyone know the AFC hack is now functioning "correctly" with dsm 450's. It's kinda annoying if you try to hold the car at zero throttle. It either wants to be off the gas, or accelarating... It's VERY hard (near impossible i find) to make the car maintain a zero load / neutral throttle position in the lower two gears. Weird. She accelarates good, reads good on the A/F through partial and full throttle driving, doesn't go lean. But the weirdest thing is happening. If I try (in neutral) to hold the car at 3k rpm, it revs there, and drops about 300 rpm to 2700 at the same throttle position, and maintains 2700. If I give it yet more gas to attempt to hold it steady at 4k, it goes to 4k, then DROPS 600 RPM to 3400, then bounces back and forth. To this, I say WTF is your problem car? o2 readings are steady as far as I can tell, I know I'm not moving the throttle and the afc's readout confirms this.. And the tuning settings are at like -35 or -36 depending on where I left them across the board. Anyone else have the hack "act up" on them in weird little ways, or is this a sign of dirty / unbalanced injectors? (I didn't clean them, I just tested all 4 to be sure they worked before putting in, 2nd Gen DSM 450's, black top).

rioninja

what your experiancing is just the drawback to running the afc hack. Your really cant complain, since you have a $400 fuel management system. For the money, its a slight annoyance.