HELP - removing my VAFC today - Honda Prelude Forum

prelude-gurl · 03-20-2003, 04:36 PM

Hi everyone!

I am parting out my car, and today my friend is helping me remove my VAFC - my question is this...

When we removed the VAFC from his car (just before it was towed by the cops yikes), the idle was terrible and the car kept almost dying - then we put it back in (when he got the car back) and everything was fine.

i dont want this to happen to my car - so when i unplug it.. what else should i do? I assume i should pull the ecu fuse under the hood for a few moments - but was there anything in the ECU that was changed while the vafc was being programmed on the dyno???

Thanks for any KNOWLEDGEABLE responses you can provide!

axio · 03-20-2003, 04:49 PM

The reason why his car was running in "limp mode" is because you guys unplugged the VAFC. There are two ways the wires are hooked up from the VAFC to the ECU. Some are simply "signal wires", where they simply tap onto an existing wire between the car and ECU. The VAFC just reads a signal from this. Other wires, which I'm gonna call "bypass wires", require you to basically cut the original wire, attach one end of the wire to the input part of the VAFC, and the other end of the wire to the output part of the VAFC. Of course, these input/output parts of the VAFC have their own wires as well which connect to the existing wires that you just cut in half. Do you see what happens now when these bypass wires have no VAFC to run through and connect to the ECU?

From Car ----- VAFC----- ECU (with VAFC installed)

From Car ----- ----- ECU (with VAFC pulled)

There's no way for the signals from the car to get to the ECU, and vise versa. So the ECU doesn't have any input/output at all for the certain variables that you used bypass wires for, and is therefore forced to run in limp mode.

If you are parting out your car, you can't simply unplug the VAFC from the black 1.5 inch harness like your friend did. You have to actually get down in the ECU (under the passenger floorboard), and cut these wires and reconnect the original stock wires.

Is it gonna take a while? Yeah, it probably will... When I installed mine, it took a while, and being hunched up in the passenger floorboard area isn't too comfortable.

There's no other way around it though. If you're parting out the VAFC, you're gonna have to reconnect the original wires or else the car will be in limp mode.

axio · 03-20-2003, 04:52 PM

Oh yeah, simply resetting the ECU (by pulling fuse for example) won't fix this problem. It's still the fact that the ECU basically had it's wires disconnected.

Once you've reconnected them, nothing has changed on the ECU itself. It's still the same settings as stock. The VAFC is basically a piggy-back system and the VAFC has settings that change. When programmed on the dyno, they messed around with the VAFC's settings. The ECU has not been reprogrammed at all. So once it's gone and the wires are re-hooked up, the car will be running like it was before you put on the VAFC.

sharkcohen · 03-20-2003, 04:58 PM

Quote:

Other wires, which I'm gonna call "bypass wires", require you to basically cut the original wire, attach one end of the wire to the input part of the VAFC, and the other end of the wire to the output part of the VAFC.

Specifically, we are talking about the MAP sensor wire. The car will not run correctly without the MAP sensor signal.

prelude-gurl · 03-20-2003, 05:20 PM

ok guys, thank youuuu!!!! I was also able to get ahold of Charles from Area51 and he had mentioned matching and re-connecting the same colored wires - that may seem like a no brainer.. haha.. but hey... im elecrically challenged.. lol.. anyways.. much appreciated for the detailed info!!! IM gonna go start the project! Such a sad sad day to see her come appart - yesterday was the intake and exhaust... *cry*

Ludatic · 03-20-2003, 05:31 PM

haha i was just gonna tell u to reconnect all the wires that u had cut before during the install =-P

BoYgUaN · 03-20-2003, 05:50 PM

u gonna be selling any parts?

Pearl-lude99 · 03-20-2003, 11:54 PM

[QUOTE]Originally posted by prelude-gurl
[B]Hi everyone!

I am parting out my car, and today my friend is helping me remove my VAFC - my question is this...

Such a sad sad day to see her come appart - yesterday was the intake and exhaust... *cry*

Looks to me like she's parting it out..

azninside · 03-20-2003, 11:58 PM

^^ true....but is she parting it out cuz all the parts are already spoken for? or is she gettin ready to sell them/put them up for grabs?

it's not so obvious

BoYgUaN · 03-21-2003, 12:17 AM

yep i might be interested in da rims
i wonder if she sold us out for a s2k....i think i would heheh