Hyundai Accent kill switch

[VersaDriver]

I've experimented with a kill switch I cobbled together that momentarily cuts power to ignition. Primarily because I dislike the fact that if the key is in any position other than "Run" the headlights go off. Hyundai's idea of battery run-down protection?

Earlier in the year doing a FAS during the daytime was no big deal since the headlights aren't on. But now that I'm driving to work in the dark, headlights are mandatory. I don't like it that the headlights cut out when I turn the key from Run to Accessory, then again to crank the engine just before a long red light goes green. Just my luck I'd get pulled over by one of the po-po's to ask me what's wrong with my lights and issue me a repair-and-report citation.

Back to the kill switch... How I made it. On the fuse panel at the lower left of the dash, there is a fuse marked "IGN" (#9). With the engine running, I pulled that fuse. The engine dies! Cool! Put the fuse back in, crank up the engine again. So now I know where to hook up a switch. I moved the 15-amp IGN fuse to a fuse holder in series with a 30-amp 12V rocker switch (that's all Radio Trash had available at/above 15-amps). I soldered 12-gauge wire - could have gone 20 gauge, wouldn't be quite so stiff a gauge of wire - to a disected fuse's. The wires connected to that fuse's blades fit perfectly into the fuse panel.

Success! Sort of... the kill switch indeed works. No need to touch the key to cut the engine, then bump start in 4th or 5th gear depending on speed. All was going wonderfully, until I checked to see if any codes were thrown by the ECU during several dozen FAS"s. No Codes Found by the ScangaugeII. However, now it reports "Not Ready". Seems cutting ignition in this manner changed the smog test readiness status from "Ready" to "Not Ready".

My thinking is that if I continue to use the kill switch, the ECU will never establish long-term fuel trim, negating what appears to be minimal gains vs my previous key-off, back to Run FAS method, all while blinking the headlights. That and the self-diagnostics routines that run during driving never complete - getting interrupted with my keyless FAS'ing. In my experimentation I got up to 47MPG in town. I can get that just by staying in gear and making well-timed use of DFCO and no FAS'ing.

BTW... I get better FE in town than I do on the freeway. I have hit a 44MPG wall at 55 MPH, down to 45 MPH when lack of traffic allows. I've gotten 50 MPG in town within my 7 mile drive to/from work when I'm "in the zone".

Anybody else's car behave in this manner, resetting the smog test readiness?

[Jay2TheRescue]

I've had a similar issue on THe Beast. I've been turning off the engine @ red lights and the DRL's flash when I turn the key off, and then again when I restart. I get around this by turning on the headlight switch before I kill the engine. Lucky I bought a big battery that can take leaving the lights on w/ the engine off.

-Jay

[theholycow]

I have a similar headlight problem, though not as bad -- if I'm rolling, my high beams turn off (and go to low beam) when I turn the key away from Run. If I'm at a stop (or come to a stop) with my engine off (regardless of key position), my headlights turn off (regardless of low or high beams). I've been accepting the high beam thing and just trying to time it with encountering oncoming traffic, and idling at red lights to keep my headlights on, but I will eventually do something about it.

Also, VW thinks that US drivers can only handle two positions for the headlight switch -- all on or all off, no way to get the parking lights (or as they call them in Europe, city lights) on without the headlights. It takes under a minute to replace it with the european-spec switch, but it's $60 that I don't have. I'm eventually going to figure out the wiring and roll my own.

Here's a few ideas for you:
- Try changing from ignition cutoff to fuel cutoff. In another thread yesterday (and many threads often) people talk about a switch for disconnecting fuel injectors. You might try that, or for the fuel pump, and see if that throws a code / cancels smog test readiness.
- Put in a more direct headlight switch (or rewire the existing one). It's pretty simple to wire up a fused, relayed circuit to operate the headlights without intervention by the computer. Then you can use the key.

I haven't properly measured (and don't have a ScanGauge to make it easy), but I'm pretty sure that I get worse FE for highway driving. My 5th gear is just too low. It uses a lot of gas cruising at highway speeds, and it makes rev-matching into too much work (although I've been practicing and do a decent job of it now, even with VW's unpredictable DBW programming). Then the car just has too much aerodynamic drag to coast well at the 70mph range I prefer for the highway.

I have no way to check the smog readiness state. My cheapo scanner doesn't do that.

Jay, why not just disable the DRLs?

[Jay2TheRescue]

You know, I actually like DRL's. It traces back to my training for driving emergency vehicles, and later on driving larger trucks for the Gov't. If I don't have DRL's I drive with the low beams on all the time. Its a safety issue for me. Someone might say look at that idiot driving with their lights on, but at least they saw me. I've had some really close calls over the years where someone was in my lane and pulled out at the very last second. I like to believe that they saw my lights and said "Oh sh**" then got back in their lane. My SG doesn't report any different fuel use with the lights on or lights off anyway. Kind of like my a/c use. There's only about a 1/2 MPG difference for a/c on / a/c off for the vehicle. Maybe it has something to do with the fact that I have an oversized alternator in my truck? I believe stock is 120 amps, and I have a 165 in it. I always like to oversize my electrical systems by about 1/3. You usually have very reliable, trouble free systems for many years.

-Jay

[VersaDriver]

"Try changing from ignition cutoff to fuel cutoff..."

Would cutting fuel delivery to the injectors - be instantaneously like injector or ignition cutoff? My Saturn would take a few seconds for the engine to die when pulling the fuel pump fuse. By the time the engine sputters and quits, I'd have to restart the engine. Haven't been able to FAS more than 10-15 seconds. Darn erratic, unpredictable, varying by time-of-day, car-presence activated (or not) traffic light patterns!

I'll see if the fuel pump fuse is in the under-dash fuse panel. I prefer to limit my electrical mods to tapping into the fuse panel vs cutting/tapping into wires. Undoing my ignition kill switch took only a moment - pull the wires out of the fuse socket and put the fuse back in its place - undetectable. I don't want to risk voiding my 100,000-mile powertrain warranty.

I haven't found the headlight relay. I was hoping I could simply jumper the relay contacts circuit so the lights would stay on regardless of key position. Again, I'm not about to cut wires and void my warranty.

I will wait until Scangauge reports smog readiness again before I attempt further mods. It took about 300 miles (3/4 a tank) to get my Saturn to go Ready status after replacing the EGR valve and clearing the trouble code.
Until then I'll restrict my key-off FAS'ing to daylight hours and use DFCO to its fully advantage in the dark.

Not many opportunities for rolling with the engine off anyway. I envy the folks that unlike me, live in hilly/mountainous areas and can FAS for miles.

[theholycow]

Originally Posted by S'Hyundai Driver

Would cutting fuel delivery to the injectors - be instantaneously like injector or ignition cutoff?

You made a good point about the fuel pump. Cutting electric power to the injectors will be more immediate.

I prefer to limit my electrical mods to tapping into the fuse panel vs cutting/tapping into wires.

You can probably interrupt injector power at the plug for the ground wire. You could buy a male-female set of that plug and not have to cut any OEM wires.

I haven't found the headlight relay. I was hoping I could simply jumper the relay contacts circuit so the lights would stay on regardless of key position. Again, I'm not about to cut wires and void my warranty.

You could deal with that one in many different ways without cutting any wires. Do your parking/tail lights turn off when you turn the key back, or just the headlights? If not, for $20 you should be able to come up with everything you need to run a complete system: connectors that plug into your headlight bulbs, wires, a relay, an inline fuse holder, and a switch. I might do something like that.

You could probably also do some testing at various points and find a place to make it ignore the ignition being off. For example, you could check the wiring behind the switch; it may be something you can do without cutting anything.

Hey, it's either come up with more ideas for you, or go change the kitty litter. I think you can see which I'd rather do.