Alright, let me outline a few things first so I can get a more accurate answer.

The car: '96 GS-R P72 OBD-II, Drag Gen III kit, rebuilt motor, 15psi boost.

The V-AFC is installed correctly. It was purchased in late 1999 when the units were first released. It's been installed and taken out of the car (3) times. The brown wire is closer to the ECU than the black. The sensor and vehicle settings are correct as I know them: In: 06 Out: 06 Cylinders: 4 MAP arrow: Up and to the right.

I have this feeling that the V-AFC isn't modifying the MAP sensor signal correctly, during Narrow throttle acceleration, the car hesitates for .5 sec as if it is getting no fuel/spark during that time. After the .5 sec is over, it continues on up the RPM band. Sometimes, the car will hit an 'invisible' rev-limiter around 6000rpm. On other occasions, the screen will start to be distorted and the car will start running really shitty, not smooth at all.

Why is my V-AFC wack? I wanted to put it back in to put the car on the dyno. Our big IDRC even is this coming weekend, and I'm going to try to qualify for the quick 8 in my daily driver. Worth a shot, but I probably won't make it. I'm looking for high 11's (at 5380 ft) which translates to a high 10 at sea level. I can't be having some stupid problems down the 1320 like some hidden rev-limiter at 6000rpm. It would spoil the day.

Can anybody help me with this problem?

 

My question is....why do you think it the the AFC causing all the problems?

What are your fuel mods?

 

Beause I just reinstalled it a couple days ago, and that's when the problems started.

<u>Fuel mods:</u>SX1000 fuel pump (good to 1000hp), Ford motorsports 30# injectors (315cc), Vortec FMU, then the V-AFC.


[Modified by Midori Shinkansen, 10:07 PM 9/19/2002]

 

Is VTEC engaging? A friend of mines car has his VAFC hooked up wrong, the 2 VTEC wires were backwards (in and out, he had them out and in). He would hit a rev limiter at around 6000. I turned the wires around and it was fine. He didnt get a check engine light either.

 

VTi doesn't, but VTo does.

 

check the VTEC wire then...

but with the screen symptoms i'd say your VAFC is dying...

 

i would contact apex'i or a rep. to see if they can help, do you ahve any of the warrenty info?

 

I think I've figured it out. Check this out--

The original V-AFC's produced came with a flawed manual. I bought mine just after they were released. The older manual says that the H-6a (P72 OBD-II) wiring diagram doesn't have use for the VTM wire input. Turns out, this is wrong-o. The Blue VTM wire that A'PEXi provides in it's harness has been left hanging by me everytime the piggyback unit has been installed, turns out, like I said, this is incorrect.

The blue VTM wire is supposed to attach to the oil sending unit wire coming out of the ECU. The wire coming from the car is left unattached. Apparently the V-AFC's manual was recalled if it was printed before some certian date. I'll make another post about this in this forum, so anyone else having the older units is alerted and fixes the problem.

Thanks for the help though guys. Now I just gotta find out which wire to splice it into. Anyone know where the oil sending unit wire is on a P72 OBD-II ECU???