Kill switch how-to

[mwebb]

Originally Posted by Piwoslaw

1A @ 12/14V, right? In my car the injector voltage is around 60V. I'm guessing that any new direct injection engine will have similar voltage.

60 volts ? on the supply side ?
is the car direct injection ?

where does it get 60 volts from ?

[Piwoslaw]

Originally Posted by mwebb

60 volts ? on the supply side ?
is the car direct injection ?

where does it get 60 volts from ?

My engine is a direct injection turbodiesel.

From Big Bang Theory: Direct Injection Diesel Tech:

The injectors are opened with a peak voltage of 80 volts and a peak current of 20 amps. This initial opening phase is extremely short - only 0.3 milliseconds. A holding voltage of 50 volts is then used to maintain the injectors' open position. These very high voltages are obtained by using capacitors within the ECU - the ECU charges these up by sending electrical pulses to the coils of the injectors that aren't working, with the resulting induced voltage enough to charge the corresponding capacitor. Weird but it works!

[IsaacCarlson]

12/14 volts. It is gas. I looked at switches today and they were rated at 30 amps. That should do it I would think....If those little tiny injector wires can take it then a good switch should be able to.

[kgwedi]

Thanks bbjsw10 for your pictures and excellent tutorial. I tried to make an injector cut off using a relay across where the FI (fuel injector) fuse was, like you showed. But the FI fuse on my 2000 Metro also supplies power to the "Main Relay" so my ScanGage would die after a few seconds.
Inline with the wires going to the actual injector is a big resister in a heat sink. I put the same relay inline there, so that only the injector is cut off when I press the switch. This allows my ScanGage to show 0 GPH and 9999 MPG. A bump start gets everything going again.
I put my switch positioned very similar to your way, except I moved it off to the side of the gear shift so my thumb pushes it. Thanks for that tip.
I believe EOC to be the best ecomod I have done to my Metro.

[drbobwoolery]

Opening the injector line allows WOT with no fuel. If the "pumping losses" are as significant as some on the EGR for MPG thread suggest, engine braking should be reduced by opening the throttle while coasting downhill in gear.
So if my 91 calif. Metro goes noticibly faster down my test hill with the throttle open than shut, then reducing output by adding EGR up to the misfire limit and keeping the throttle open will pay MPG dividends. If coasting down the hill in gear, inj. off, throttle open does not go faster than throttle closed, then the increased EGR is a dead end.

[mwebb]

if the engine is not running because the
injector supply has been opened
then
the car should be rolling in neutral and the engine should not be turning

so
while interesting to ponder , there is no reason to use engine braking for this condition
============================
EGR does improve FE ...
where are you going with your comments on EGR ?

Originally Posted by drbobwoolery

Opening the injector line allows WOT with no fuel. If the "pumping losses" are as significant as some on the EGR for MPG thread suggest,

engine braking should be reduced by opening the throttle while coasting downhill in gear.

So if my 91 calif. Metro goes noticibly faster down my test hill with the throttle open than shut, then reducing output by adding EGR up to the misfire limit and keeping the throttle open will pay MPG dividends. If coasting down the hill in gear, inj. off, throttle open does not go faster than throttle closed, then the increased EGR is a dead end.

[drbobwoolery]

responding to:

while interesting to ponder , there is no reason to use engine braking for this condition
============================
EGR does improve FE ...
where are you going with your comments on EGR ?

Claims of increased efficiency with max EGR short of misfire are mostly based on reduction of pumping losses, restriction across the throttle plate, etc.
If there is much to be gained with the cam, compression ratio, exhaust system by reducing pumping losses, this should be evident in downhill coasting in gear with the fuel off, comparing the OEM throttle closed drag with the drag associated with WOT. If it is difficult to decide about the effect in this situation, the pumping losses are small enough to not be worth trying to reduce with EGR.
OTOH, if opening the throttle feels like letting off the brake, in gear, no fuel, then there IS something to be gained.

[dennyt]

I have an injector kill switch in my car. I have played with the throttle descending steep hills, and I can't feel a difference between WOT and closed, in low gears or high gears. Of course it sounds different, but there's no perceptible change in deceleration.

A coast-down test might quantify things.

[mwebb]

since we know that
what ever EGR percentage is on an OEM system does yield improved FE over 0 percent EGR

it is not a far stretch to deduce that INCREASING EGR flow percentage up to the point where misfire is induced OR efficiency is reduced
should also improve FE

testing
in the real world on a real car with real test equipment would be needed to see
how much EGR flow could be increased , it would have to be regulated and increased a wee little bit at a time
changing exhaust back pressure will screw up the EGR modulator 's ability to control EGR flow ....
another failed experiment

i have inadvertently increased EGR percentage by changing cam timing on a G10
the exhaust valve closed before all the spent combustion gases could be expelled
FE was not improved and drivability was reduced
DO not use the 3tech +10 cam wheel with the 3tech economy cam or you will repeat my inadvertent experiment


the 3tech economy cam by itself is an improvement with the OEM cam wheel
.............................
just because 2 experiments failed does not mean that it can not be done
a bit more testing is needed .... and time always has a way of flying away before the testing can be done

Originally Posted by drbobwoolery

responding to:

while interesting to ponder , there is no reason to use engine braking for this condition
============================
EGR does improve FE ...
where are you going with your comments on EGR ?

Claims of increased efficiency with max EGR short of misfire are mostly based on reduction of pumping losses, restriction across the throttle plate, etc.
If there is much to be gained with the cam, compression ratio, exhaust system by reducing pumping losses, this should be evident in downhill coasting in gear with the fuel off, comparing the OEM throttle closed drag with the drag associated with WOT. If it is difficult to decide about the effect in this situation, the pumping losses are small enough to not be worth trying to reduce with EGR.
OTOH, if opening the throttle feels like letting off the brake, in gear, no fuel, then there IS something to be gained.

[watercat]

So tonight i installed my kill switch and my manual throttle. I followed some one else's advice on here for the throttle and got a bike shifter and installed it on my shifter in the car. I will get some picts or video and post that but it installed in 20 minutes and looks like geo sold it on the car.

On the kill switch i unplugged my starter clutch pedal switch and simply plugged a fuse into the wires to leave the cars starter circuit closed so it will now start in gear. I then used a relay that was normally closed and cut the red wire to the distributor. i lengthened this red wire on both cut ends to reach the fire wall where i mounted my relay. i then ran a fused power wire to my clutch pedal starter switch and another wire from the pedal switch back to the normally closed relay and then of course i ran aground to the relay using the grounding bolt that comes from the fire wall to the distributor for the factory block ground.

So now i just have to get use to not shoving the clutch pedal to the floor completely and it shifts just fine. I set it about 5 clicks on my shifter throttle for 50/55 mph and when i come over a hill i simply shove in the clutch the car coasts and the engine instantly dies and as soon as i release the clutch it instantly starts up and goes back to maintaining its set speed on the manual throttle. I drive about 35 miles each way to work and i did pretty good for my first drive home only killing it a few times in town.

i will be installing a toggle switch that breaks the power to the relay so that i can drive the car normal and depress the clutch pedal completely and not have it die so other people can drive the car or if you got in a place where you were shifting a lot or in stop and go traffic you would not have the stalling issues.
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