Kill switch
 

Today did engine off coasting and am thinking that's the only way to go. I need to install an engine kill switch. I guess ignition would be the best and easiest to do. So would I just need to get a single pole switch and splice into the power supply to the coil pack? There are three wires coming out of the coil. Red,Black/white and green. Accoroding to the wiring diagram the red and the green go to the PCM and the black/white go to GRN. So would I just need to splice the red wire? Also does anyone know if a kill switch will keep the scangauge alive or is there something else that would need to be done for that?

Can't you just make a kill switch by adding a switch into the ignition so that it will cut the constant flow of power that makes it think it's in II (run)?

i sure can use a kill switch for my car :( that means i need to touch wires NOOOO!

I made the kill switch for my car because switching the ignition off via the key - even for just a second - put the ScanGauge to sleep and screwed up my FE feedback.

I borrowed an idea from Dan, and spliced into one of the pickup coil wires on the distributor. Not sure what to do on distributor-less cars however.

Someone on the TeamSwift site asked me how to do this, not for the ScanGauge, but because he was a little wary of using the key while driving (concerned about turning the key back too far and accidentally locking the steering).

What's your motivation for the switch, zpiloto?

Yesterday I had a bunch of driving, 100 miles, (60 which was highway) and decided to try some engine off coasting. Was able to boost the trip milage by 4.0 MPG with 8 mile of engine off. With the aero mods the coasting is really good and I had several places where the coast was better than .5 miles.

But as you know the scangauge dies and you have to mess with the key. I was thinking that if I went into the coil pack power supply(sounds like the same thing you did) I could kill the engine with out losing the scangauge data. So I'll try a tank with the coasting and if the transmission doesn't complain my plan is a kill switch and push button starter using SVOboy DIY.:D

I thought that's what I would be doing with ignition cut out. But I'm mechcanicaly challanged. I have to study it carefully.

I think the ScanGauge needs to see "II (run)" to stay active. Sounds like you need to interrupt the spark, like I did.

Once you have steady feedback from the SG and you see what engine-off coasting does to your trip average, you'll be hooked :)

I'm already hooked.:) Just need to figure out how to make it work.

how about installing a cut off switch on the fuel injecters? so insted of killing the spark and still having fuel dumped in for a few rotations, it just stops injecting fuel, each injector has I think two wires, either one should kill it, you would need a normaly closed, 4 pole butten switch.

I'll look into that. When you turn the key off does it kill the fuel or ignition or both?

I too am interested in doing the "injector kill switch". since my metro has only one injector it should be pretty simple. I'll try interuppting the circuit but if the engine computer starts throwing codes then a complete bypass circuit should work (like a heavy 2 ohm resistor or something).

If the injector switch makes the computer mad, a switch on the distributor coil pickup wire instead keeps it happy (provided you don't try to start the car with the switch "OFF").

I have a coil-pack ignition. I also had 3 wires. Unplug at coil. Take a test light, turn the ignition key on and the 1 hot wire is it. I found a nice switch at Advance Auto, about 5/8 inch round that depresses 1 side of the button and back. Also had a small led, good for dark nights. Splice the switch between the harness and coil, you're done. I first asked Metro about what he used way back before I was a member of GS.

Won't your ScanGauge stay alive if you key off then back on? You do have it set on hybrid, right? With the kill switch installed your ignition switch operates just as it did before. You just don't have to fiddle with it to kill the engine. The switch button just has to be on to run.

I did try wiring the switch between the engine fuse block lugs. It shut the engine off OK but also cut the power to SG at the same time. Maybe more.

With the hookup described above only the ignition is disabled by switch, everything ese that is on with ignition is still on.

Since then I have replaced the ignition kill with injector shutoff. I like this a lot better. The engine kills sooner and restarts cleaner. I actually used the same wire and switch I had used for the ignition kill.

since my car was stolen i redid a good chunk of wiring around my relays. so now i have a kill switch and i remove one of the relays.

i refuse to give specific online. i am sure most of you understand. anyway, i use it for security, not for engine off coasting.

Did you get your car back? Or get a different one?

Kill Switch usage?
 

Hello -

It sounds like some of you have a button that kills the injectors only as long as the button is depressed. Is this correct?

Question : For manual transmissions, do you press the button when the car is in Neutral or when the engine is engaged (i.e. the top gear, 5th gear in most current cars)? I ask because I think that if the transmission is in Neutral, the engine should turn off and require a bump-start. If the engine is in gear, I think it would just fire up as if nothing had happened.

Am I right? Which is it?

CarloSW2

cfg83, I replaced my ignition shutoff with injector shutoff. No need for both. Will kill engine in or out of gear. When I switch injectors off, engine dies immediately, quicker than it did with ignition kill and restarts cleaner. It does require a restart, either key or bump. You could rig a start button if you have an automatic that won't bump start.

CO ZX2 -

Thanks, I have a manual, so my life is easier for this stuff. I like the injector kill switch idea too. I know how to do the bump start from Neutral, so that is easy. I was hoping that when the car is in gear, taking my finger off the button of the kill-switch would restart fuel to the injectors, and would therefore restart the engine without having to bump start (less work for the driver). But it sounds like a bump-start is required for the Neutral or in-gear situation.

I was asking because from what I know about my car, it doesn't have an efficient "auto fuel shutoff" when my foot is on the brake. Hypothetically, when I am on the brake, in gear, and above idling RPM, the engine doesn't need much or any fuel to keep turning over. I have been told that this does happen for most fuel injected cars, but I can't gauge how my Saturn does this (at least not from the ScanGauge readings that I am seeing).

CarloSW2

cfg83: I was hoping that when the car is in gear, taking my finger off the button of the kill-switch would restart fuel to the injectors, and would therefore restart the engine without having to bump start (less work for the driver). But it sounds like a bump-start is required for the Neutral or in-gear situation.

If you are in gear engine will restart when switched on. Just the same as bump start. Why are people so paranoid about Engine Off Coasting, one of the most FE efficient things you can do??

CO ZX2 -

Great, that's what I wanted to hear. Please remember that I know *nothing* about cars. I was never a wrench monkey. When I had my CRX I opened the hood maybe 5 times in 5 years, and took pride in that (but am ashamed today). From what I can tell, at least 50% of the people on this forum have the car skills to swap a tranny if they want to. Everything I am learning right now is new for me (wide vs narrow band 02 sensors, what is that!?!?!?!).

Also, this is a forum that is *supportive* of this stuff. In the real world, I have to defend myself from very many detractors. My mechanic, who I have found to be very honest, didn't want to touch a fuel heater idea because of the fuel pressure/safety factors, and he has been working on cars since he was 12 years old.

If I kill this car, then it's off to the new car lot for me. I don't have the skills to fix it.

CarloSW2

cfg83: If I kill this car, then it's off to the new car lot for me. I don't have the skills to fix it.

Does this mean you think Engine Off Coasting would ruin your car??

CO ZX2 -

It means that I don't know if Engine Off Coasting will hurt my car or not. I don't know the physics of it. I think I know that I am "tapping the flywheel" to turn the engine over, but that's about it (sometimes I can do a really clean "bumpless" tap at 30 MPH in 5th gear). A good chunk of this time I read this forum and I then go and do alot of "homework". Part of that involves reading long threads in this forum and part of that means going into the nether-reaches of the net to figure this stuff out.

CarloSW2

Carlo, I am not chastising you or anyone else. I am just trying to help those who seem to be interested in FE. In my opinion and experience, I consider the strain on a transmission to be negligible compared with coasting in gear. Either way you are feeding the power backwards from the wheels to the engine. Engine off you are not feeding power backwards except at the instant of bump start.

For a while I have been bump starting in 4th gear below 40 MPH. I do not bump start below 25-30 MPH very often. Real slow bumps is where the jerking happens.

A while back I read in a GS post, that Dan Krouse on his commute, had his engine running 34% of the total time. I have not measured my own % but would not doubt that it is in the same area. Remember, when the engine is off, you are using no fuel.

CFG83: Their is some difficulty in answering your questions, for several reasons, none of which have diddly to do with you knowing or not knowing anything about cars. I think you'd find that most the people on here know something, largely because their are a lot of things that just don't seem to get done like you want, unless you do them.

As far as the kill switch, it's use, it's effectiveness and so forth, a lot of that is related to the car you are driving. For example, I am driving an 89 Honda Wagon, which is basically a DX in a box. I put a kill switch in, but I quit using it, for several reasons. Primarily, for me, it came down to the fact that if you turn off the engine, the oil pump is no longer pumping, and consequently each time you restart, you have a period of time when the engine is turning with little or no oil pressure.

I hate working on my car, consequently the savings which I was getting was not worth it, IMO, in relation to the potential wear and tear. Added to this, a restart puts an additional requirement on either the starter, or on the clutch/flywheel. In either case, same, same, no likey unnecessary repair.

Finally, on my Civic, I would always get a CEL whenever I killed the engine, irrespective of how I did it and I would have to turn the key off, then back on and it just got to be a potential distraction issue.

Also, with regard to Oxygen sensor's, I have a 4 wire sensor, which I wired in so I could monitor the voltage. What I discovered was that whenever the throttle is closed, the fuel shuts off as long as my rpm is over 1250 rpm. Consequently, most of the time, my fuel would have been shutting off, anyway.

Regarding O2 sensors, a 1 wire and 4 wire unit both are narrow band sensors. They both measure the same thing and are designed around 14.7 to 1 as an optimum air fuel ratio. They typically are utilized by the ecu to control the fuel by putting in a little more, until the voltage goes up and then putting in a little less until the voltage from the sensor goes back down.

A wide range sensor is typically 5 wire, and can sense a much leaner fuel condition and report it to the ecu. However, the ecu has to be one programmed for the wide range sensor. Up until recently, the 5 wire unit's were used primarily for ecu tuning and in Honda Civic VX's. Consequently they have not been in great supply and therefor were significantly more costly. If you have a car that requires one, it probably is something which will get better mileage. If you don't, you can theoretically make the changes to accomodate one, but unless your into twiddling and fiddeling, it isn't probably something you would want to do.

If you have any questions, or you decide you want to get your hands a bit dirty, just give a shout.

In CA., you can normally still manage to work on your car, if you have to. However, the cold winds which we've had make it pretty miserable, recently.

CFG83: the kill switch I imagined (and some use) is a momentary contact, press it and the engine dies. release it and you have to spin the engine up again via starter if stopped or bump start if moving, or if you never took it out of gear it will have powr again.

re trans wear, if your car is the sort that is towable behind an RV then no worries. If not then still probably no worries, but not a guarantee. This mostly applies to automatics but I think some manuals (i.e. old volkswagens) wont move the tranny oil to all the right places without the input shaft turning and those spots wont get as much lube as normal.

i got it back and finally got it on the road. its loud.

Gary -

Ok.

At least that's not an issue for me with key off/key on. The check engine light goes away when I bump start.

That's probably different for me. What I have gleaned from the saturnfans.com website is that the fuel injection is reduced but never quite off. Your Wagovan's behavior makes sense to me.

Honda ECU Programming Rule:

closed = 0
idle = 1250
if (( throttle = closed) and ( RPMs > idle)) then fuelInjection = 0

Ok. I have the digital A/F gauge from jaycars.com.au. *After* I received the gauge I realized it preferred a wide band 02 sensor. My Saturn only uses a narrow band. Later on the gauge designer responded to my e-mail and told me that it will still work for me. In the meantime I spent a week trying to figure out the difference between 02 sensors and whether or not it would work on my Saturn. I want to splice into the same sensor (not a separate standalone 02 sensor) that my car's computer uses because I want to see what the car's computer sees when it comes to the 02 reading.

Tell me about it. I burned my finger on the cigarette lighter on Saturday and iced it into a callous. On Sunday, I was staring at stuff under the car for my next "mad scientist" project, and when I got into the house, I couldn't tell which finger was burned because they all felt like they were calloused from the cold.

CarloSW2

skewbe -

Ok, this is what I was failing to describe properly, a "momentary contact" switch. The "never took it out of gear it will have powr again" is what I was hoping to hear. In fierce LA traffic, I would need "instant power", so to speak. With a switch like this, I would be able to emulate Gary's Honda Wagovan behavior (that he gets for free!!!! :mad: ).

I have a manual transmission. This sounds like a saturnfans.com question. I seem to remember that Saturns are "RV-Tow" friendly, but that's about it.

CarloSW2

CO ZX2 -

No offense taken. :thumbup:

That is a question I have that is more relevant to this thread. What are your "bump start" rules after you have activated your kill-switch? My LA traffic makes freeway bump starts problematic. I do have a few zones along my route that I think are bump-start friendly. Here are my bump start rules :

- Relatively flat road that I know
- No one following me
- 40 to 45 MPH speed limit
- Spedometer usually at 40 to 45 MPH
- Key off, wait 1 second, key on (or kill switch if installed)
- Coast down to 30 MPH
- Bump start in 5th gear

If I tap the flywheel just right and push the clutch pedal back down real fast, I don't even feel the bump.

Ok.

CarloSW2

ok, starting on the kill switch.
 

Here's one idea for a kill switch refinement.

I was thinking of locations for the switch and decided the index finger on the shifter hand was best. It should be super easy to get to, like easy enough to use even during shifting or during engine braking (according to my scangauge the car is still using fuel while decelerating in gear), and especially coming up on stoplights/etc.

The wires are hooked up to the "Normally Closed" part of the switch and will be run down the boot, under the counsel, and through the firewall and in series w/the injector. Hope the switch can handle the current.

Now only if my urethane glue job would hurry up and dry :)

https://www.gassavers.org/attachment....4&d=1169254223
https://www.gassavers.org/attachment....5&d=1169254241

What version display did you get? The 5301? I can help you set it up for the narrow band O2 sensor in your car. I just finished assembling mine today to hook up to my VX O2 sensor to tell when I'm in Lean burn.

Off hand I can tell you that if you have the Jaycar 5300/5301 and want to use it with a narrow band O2 just assemble it per the Jaycar instructions and ignore the changes indicated by Tech Edge.

If you feel your electronics prowess isn't up to the task, you could mail me the unit and I can assemble and calibrate it for you.

TomO -

Thank you! I know how to solder, but the calibration part looks pretty depressing, so I would appreciate help on that. I thought the VX 02 sensor was the 5-wire job. Is the 5-wire a narrow-band too? Does the VX have two 02 sensors like my Saturn? I would be slicing into the unheated (2-wire?) 02 sensor in my exhaust manifold, not the heated (4-wire?) 02 sensor that is located after the catalytic converter.

I have the 5300 :

https://www.jaycar.com.au/productView...Max=&SUBCATID=

CarloSW2

The O2 sensor in your Saturn's manifold is most likely a 1-wire model like it is in my '99 SL2. The 5-wire sensor that you mentioned is a wide-band sensor.

Getting back to Kill Switches ;)
 

Test drive went well, didn't take long to get the hang of it. I covered a lot of ground with the engine off and didn't sit for more than 8 seconds with the engine running. killing during shifting didn't work so well, but I only tried when it was cold and it would die completely, needs work.

The injector resistor is HUGE (purple circle), I'm a little concerned about my little switch. But I have an alligator clip and can jury rig the leads back together if necessary :) A relay would provide more peace of mind, but cei la vie. I'll keep an eye on the mileage. Last tank sucked.

https://www.gassavers.org/attachment....1&d=1169270520


https://www.gassavers.org/attachment....1&d=1169270535

diamondlarry -

You must be right. I recall that it does look like a 1-wire sensor. I was looking online and saw 1, 2, and 4 wire models for Saturn S-Series. Which 02 sensor is post-cat in your SL2?

CarloSW2

I have a question about the kill switch use:

In order to eliminate the "bump" start could you:
1 Kill the injectors
2 leave the engine engaged
3 open the throttle fully to reduce pumping losses/alt still charging (REGEN BRAKING?)
4 finishing coasting but still be in motion (rpm about 1500)
5 close the thottle while still rolling
6 start the injectors

The bump will be removed....saving a tiny bit of clutch material.

Bill

My post-cat sensor is a 4-wire.

By doing it this way(leaving engine engaged), you will significantly reduce your coasting time to the point where it may do little or no good for FE.

I think you're right. Even with the throttle open and spark plugs removed, the engine friction would be significant, and the benefit of the engine-off glide would be lost.

The proof of the pudding:

Stop on a grade. Kill the engine. Now, with the engine in gear, open the throttle fully. Does the car roll? Didn't think so!

I'd be interested to compare coast length of both methods just to see how different they are.

Nice work, skewbe. I thought I was looking at a picture of MY gear shift :) Except my switch is held on with a hose clamp. (I graduated from duct tape when it got really hot in the summer and the tape got all slippery & gooey.)

I should try the injector kill, because I'm conscious of the fact that sometimes the engine doesn't die a quick, quiet death when I press the button (it occasionally seems to spin an extra rev, half-heartedly, which could be due to the injector providing a last dribble of fuel.)