Cutting the wire hasn't caused any mechanical or electrical problems in my car. Same goes for PJK3 who did it for me. And if opening and closing it at speeds in excess of 15 mph I could imagine it hurting if not severly breaking the top. But that could very well happen if you try opening or closing the top when there are gale forced winds out. Being the owner you should be smart enough to tell whether or not the conditions are safe enough to do this.

On a more positive note, having this feature is really convenient in case you are in a rush or if it starts to rain. You can slow down on side of the road if it starts raining and while going at a slow pace on the shoulder you can raise up the top rather than coming to a complete stop. Or if you leave your house and driving to get out of the neighborhood, you can lower the top while cruising slowly down the road.

Of course some may not see this as necessary, which it really isn't.. it is simply just a convenience feature that can be done to your car.

 

Chitah,
Your VSS is used by the ECU. Period.

You will not have driveability problems because your ECU and O2 sensor are hiding it from you; it's a conspiracy.

Typically, the computer will use your VSS to interpret tranny line pressure (only on automatics), as well as air/fuel, spark advance, EGR (S2000 doesn't apply, of course), among others. When you remove the VSS, you're taking away the VSS signal. No big deal, but in actuality the ECU will see that as a faulty sensor, bypass it, set a fixed value for the sensor, and reference a similar (in-limit) sensor like your TPS (combined with MAP).

That way, the car will still run fine. Driveability.

With that said, your car may run cherry, and pass a 5-gas with 0 emissions and high CO2, but you'll be burning a lot of gas as the computer accommodates the lack of VSS. Removing the VSS can quite possibly cut your fuel mileage in half (the ECU will constantly run rich).


Put it this way: Think of your O2 and the ECU as the head guys (management) of an illegal money scam within a large business. All your other sensors are the labor, and whenever they screw up, the management will do whatever is in their power to cover up the mistake, just to save their asses and not get caught. Likewise, when your sensors go haywire (or are manually bypassed), the ECU will "fix" the problem by adjusting your other parameters.

 

That's interesting, Alex. Are you sure the wire that Chitah is talking about is the signal in question? Just checking.

 

Well, I haven't checked it personally, but from the several threads I've read on this subject, everyone seems to be cutting their VSS wire, which is a big . It'd be interesting to know if any of these guys (Chitah?) have been having fuel economy issues.

Also, when the ECU bypasses stuff like that, it will set a soft code, not a hard code. A soft code just runs in the "background" and doesn't throw a CEL. You can only find them with a scanner (or manually pulling codes).

 

:goes to bedroom to consult wiring diagram in Service Manual:

 

Hmmm that is interesting. Makes me want to put the wires back together. If you can double check to see if this wire is the white wire with a black line.

My fuel economy really hasn't changed. Driving mixed highway and city I get 25 mpg... and that is with plenty of VTEC. Let me know if you find anymore info about it...

 

Note: The "Basic Operation" section says "The vehicle must be parked or traveling at no more than 3mph"

This explains how Wanabe was able to be moving and still muck with it. I didn't know you could do that.

The wiring diagram is not telling me what I want to know, except that it does appear as if the parking brake switch and "VSS Signal Driving Circuit" are the two relevant inputs here. I think Alex is right, though I can't conclude that cutting the wire actually cuts this signal everywhere. Perhaps it's only cutting this signal into the Convertible Top Control Unit (under the passenger dash)... Dunno.

 

(oh, before I forget, there's also a disable switch that gets used for hardtop installation; didn't know about that one!)

 

AHA!

That's gotta be it, Chaz. Since the wire is easily accessible (and under the dash) and because Chitah hasn't experienced any fuel economy issues, I'm beginning to think you're right about that wire only passing the signal to the CTCU.

I'll pull up some spec's tomorrow, see what I can find.



But this still doesn't explain how Wanabe was able to put the top up while moving, withOUT cutting the VSS wire. Unless, as Chitah guesses, Wanabe was doing less than 3mph.

 

Excellent.

Yeah, this damn service manual is a tease. The female connector on the CTCU is where this "wire" is actually found, Alex, and from what I gather here it's B6 on the connector and it's a white/black wire. What I can't tell is how this signal is distributed through the car.

Very interesting... The "Test condition" for this signal says "Ignition switch ON (II), raise the rear of the vehicle, and rotate one wheel slowly". My brain hurts!

If I built a computer like this, well, I can't imagine it'd ever work!