My car's sitting on the dyno as I type, but we're having problems with the vafc controller. Looking at the curve, it looks like it's not transfering from low vtec to high vtec at all. We had to add a ton of fuel I guess with the fuel pressure regulator? We tried taking fuel out (-14) and it doesn't look like it took any out at all. Does anyone have any ideas on what I can do to make the high vtec kick in or what we may be doing wrong to subtract fuel? The controller is getting all the readings...throttle, rpms, etc... so I think it's hooked up correctly.

Any help would be greatly appreciated.

Thanks,
Dave

 

It sounds like your V-AFC is not connected to the VTEC solenoid wire.

 

while I'm waiting for them to check that...to double check...the vafc cannot add fuel correct? It can only subtract fuel?

Thanks for the quick reply also!
Dave

 

what color is the vtec signal wire on the ecu?

 

[QUOTE]Originally posted by bgbfflochp
[B]the vafc cannot add fuel correct?

 

The V-AFC doesn't add fuel well, since it makes the ECU think there is boost.

I don't recall what color the wire is...

 

Sorry if the following is jumping from topic to topic...and for the what appears to be long enough for someone's final thesis on rambling and confusion...but please bear with me...

Ok, here's the deal. I put a smaller pulley on my comptech supercharger (4.25") and went to get it tuned today. I've got an even smaller pulley on my other S2000, tuned it...no problems whatsoever...pushing 366 to the ground. I lived in another state, so I guess the guy at the dyno there knew more about tuning S2000's? Anyhow...I threw a comptech SC on this one, dyno'd at 273 to the ground in the winter. I put comptech 4-1 headers and testpipe on it, got it dyno'd at 252 to the ground (granted it was much warmer). Now, I've got V-AFC, intercooler and a smaller pulley, and the top run was 267 to the ground. We had a loose wire earlier on, causing it not to take any fuel out....we played with the wires and it worked fine after that. Now before I put the smaller pulley on, I installed an intercooler. After the install, the car sounded funny and the gas pedal felt a little different from 4000-5000 rpms. The noise seemed to be coming from the SC, like the air was struggling to get in from the filter. After 5000, it was fine again...and it didn't matter what gear I was in. After we figured out the V-afc wiring problems, the car would just cut power (hp) at 4400-4800 rpms...major drop off, and then it'd go right back up. It would do this 2 out of 3 runs I would say. The car hesitated, then jumped right back into sync. My question is: how could the intercooler possibly cause this? It started when I got the intercooler installed. I can't figure any reason why the intercooler would affect this in anyway. If not the intercooler, any other ideas? Also, any ideas on why only 267hp? I'm going to try and take my other S2000 to get dnyo'd to see how much the heat takes off of it.

The 366 hp S2000 has a built engine, smaller pulley than the other S2000, and a different intercooler. Those are the only differences...both are 2001, and have the same 'other' mods.

One thing though, do you think the ecu is causing the major dropoff at 4400 rpms? Do you think it would help if I reset it (of course I didn't think about that at the dyno).

Again, I appologize for the length of this post. I will also try to get some charts posted on here tomorrow when I can get them on the computer.

Thanks for any help if anyone read this far!
Dave

 

You should probably start another thread with a more appropriate title like "Tuning problem with my SC / V-AFC". You need help from the FI crowd.