M-EJ1

I'm still fighting with a poorly running car after performing the VAFC hack. Here are some symptoms: Very rich idle according to my autometer gauge. full rich, gauge does not swipe back and forth like it should in closed loop mode, random CEL 43's (fuel system delivery error) while cruising (not boosting), backfires when I let off the throttle around 2500-3000 rpm. Timing was advanced into the stratosphere (something like 22 degrees). Car idles like crap sometimes, idles fine others, detonates on top end no matter how much timing I take out and how rich I set it, car seems to immediately switch to closed loop once I get on the throttle, and it never goes to open (not even when I stomp on it from a slow pace).

So, my question is, how does the VAFC hack affect the ECU's closed and open loop settings, if it even does at all? It seems like my car is in open loop when it should be in closed and vice-versa... cruising along at about 65-70 in 5th gear the A/F reads fully rich, and never anything else, and when I push it a little it goes to closed loop and then stays put until I let off the gas.

Also, what do the throttle point settings that everyone puts at 98% and 99% do? Apex'i's manual for the VAFC is pretty much useless when it comes to explaining some of the features, so any help there would be appreciated.

I've been told some of these issues may be due to a fouled or bad O2 sensor, which is something I need to look into, but the dealership wants 220 bucks for one after taxes, and they would have to order it so I can't get it until next week. Not only do I not have 220 bucks to spend on the stupid O2 sensor, but I need to figure out what's wrong with my car soon because I have a long trip to take on Sunday. Can a "fouled" O2 sensor be cleaned or "un-fouled" at all, or would I be wasting my time?

Can anyone give me any suggestions here? I've played and toyed with my fuel correction settings until my fingers are numb, nothing changes (unless I lean it out so much at idling that the car almost dies, then it goes into closed loop at idle, that's about it). There's definately something fishy going on here... everyone who knows me says I'm crazy, but I've been driving the car since the day I first boosted it and it was never this sluggish or unruly when I was running the bluebox as my only fuel management means.

Joseph Davis

Wierd problems. Do you have the AFC grounds connected as per the instructions? What you are experiencing is *not* common.

Honda ECUs go into WOT/open loop when the TPS voltage goes over 4 volts, or when there is a quick enough change in MAP voltage. Part throttle cruising leading into part throttle boosting (pedal variation of 5% involved) lodges me firmly in open loop for the entire boost event.

I've kicked code 43's before at cruise when I first had the AFC boost hack, but after I changed the O2 sensor and fiddled the tune a bit it went away.

Pig rich idle is something you might have to live with unless you alter the ECU fuel pulse at idle. Some people have good luck with it, I was borderline, and some people are stinky rich. I think yours is related to the problem at hand - grounds.

Good luck with it...

M-EJ1

Hmm... that's an interesting take... I do remember making sure that the grounds were lined up right, however, after doing some research I learned that I should have put them at least an inch apart... I don't recall how far mine were apart, but probably not up to an inch apart... more like .5 inch from each other. Does that sound OK? The manual made it sound as if they should just be one before the other, but distance didn't really matter... maybe I didn't read that clearly enough.

zojirushi

i'm also curious about cleaning an o2 sensor... mines about pure black!

Joseph Davis

Uh, I vaguely remember they were supposed to be a few millimeters apart, no more no less?

Check the vehicle grounds, too. The ECU is acting generally wierd, not just MAP input related.

M-EJ1

Checked my grounds, everything seems fine, checked my VAFC grounds and everything's good... just about half an inch apart with the brown wire first towards the ECU. The Apex'i manual doesn't say anything about how far apart or close together they need to be, so maybe I've got something wrong there...

Anyway, I'm going to pull the O2 sensor tomorrow and look at it. Is there anything I can do to clean it (whether temporary or permanent)? I just do not have the funds to get a new sensor right now so if I can even make it work temporarily that would be nice.

Also, I have another MAP sensor I'm going to test on the motor, but I think the stock one is OK.

Anyone have any other suggestions as to what might be happening here given the symptoms I described?