jwzimm

Hey all,

I was reading through the Crank Walk discussion thread and I decided I wanted to figure out a way to configure a clutch bypass so I can start the engine without engaging the clutch to prevent wear on the thrust bearing. This is a pretty common mod but I added a small twist. I wanted to retain the clutch interlock in case someone else has to drive the car. I opted to, instead, wire in a shunt from another switch on the dash that will short the clutch interlock wire to ground when pressed. I chose the VSA OFF button as my secondary bypass as it goes to ground when pressed and is momentary (so it will not stay closed when released). The wiring was very simple. I tapped the light blue wire at the clutch interlock switch and the white wire in connector C303 under the steering column. I connected these taps with a jumper wire thereby allowing the ground signal from the VSA switch to close the interlock circuit and allow the starter to engage. The one rub is that I needed to prevent backfeeding the VSA circuit from the clutch or VSA would engage and disengage every time the clutch was pressed. This was solved with a simple diode in the jumper wire with the cathode toward the VSA wire.

I am now able to start the car by pressing and holding the VSA switch and then pressing the ENGINE START button. The VSA does switch off when you do this but that is easy to turn back on by pressing the VSA button again. The engine is still able to be started by engaging the clutch as well so 100% OEM functionality remains.

Another possible option with this is you could set this up as a kill switch as well. All you would need to do is disconnect the interlock switch connector at the top of the clutch. In that configuration the only way to start the engine would be to press and hold the VSA button first. Only someone who knows about this would be able to start the engine.

Just thought I would share.

fernando.

The latter idea is actually brilliant and I may consider doing it.

silverstone_f22

Definitely a cool idea especially for anti theft. Reminds me of the old Integra cruise control push button start.

freq

If you have a VSA button.

I'm kidding, great idea.

fernando.

I would use my rear defrost or roof button since I don't use either.

jwzimm

Thanks guys.

Originally I was going to use the Cruise control buttons on the steering wheel for this but I ran into a snag. The CC buttons use the 12V from the horn relay to feed into the ECM. Since this dead-heads it doesn't cause the horn to honk when you press the button. I was going to use a small relay to switch the 12VDC output to ground to feed the interlock but the current used by the relay may have activated the horn which would not be desirable so I scratched that idea.

You can really use most any switch or button in the car for this. I poured through the electrical diagrams manual for each switch to see which ones would work and landed on the VSA OFF button. The thing to watch for is if the button you wish to use goes to ground or to 12VDC when pressed. If it goes to ground that is an easy jumper with diode. If it goes to 12VDC you will need to wire in a small relay to convert the signal to ground. I was planning to use an ELK-912 relay module for this purpose.

Really the hardest part of this this whole thing was cramming my 200lbs butt under the dash to do the wiring. I felt like a T-rex with tiny arms trying to do surgery down there.

WeS2kay

Maybe you can answer this, whats the best kind of wire to use to jump the clutch bypass connector with? Should I just go and get some 16 gauge wire and bend it around and just tape it in with electrical tape? On a side note, good lord is is uncomfortable laying under there trying to reach that connector. Took my seat out last night to hopefully make my life easier.

jwzimm

Honestly not sure as I did not disconnect the interlock connector. I would think a solid conductor with the proper diameter would be the best at fitting into the contacts in the connector and staying put. Don't over think it though. You are just shorting a plug. Whatever does the job and stays in place will work.

WeS2kay

Do I put the wire that I am using to short out the connector on the connector that is attached to the clutch or am I shorting out the wire that I unplugged? I'm guessing the one that is unplugged from the clutch and not the one that is on the clutch right? I'm not sure if that makes sense so let me know if it doesn't

jwzimm

Shorting the pins on the switch attached to the clutch would not do anything (it is just a switch that connects the two pins together when the clutch is pushed). The wiring on the car side of the connection is what goes to the interlock relay that will allow it to start the car. You would short the two contacts on the connector together, thereby bypassing the clutch switch and allowing the starter to crank at all times (regardless of clutch position).

Personally, I do not like this approach though. It carries significant risks of accidental starter engagement. Since the clutch interlock switch is bypassed, any time you push the ENGINE START button the starter will engage. That includes if the car is in gear (the car will start moving on the starter power) and if the engine is running (really bad for the engine and the starter). My solution still maintains the clutch safety interlock but allows the driver to bypass it if needed/desired by holding the VSA OFF button first. That extra step means that it is far less likely for the driver to mistakenly fire the starter as it is not a normal procedure one would follow.