OMGuar wrote:CowDriver wrote:If you do use a big capacitor for the ECM, be sure to put a diode in series with the battery line (just before the capacitor). You don't want the capacitor discharging through anything other than the ECM.
I hope your reference to the 100 amp fuse was for the line from the battery to the kill switch! :-)
I'm sure the ECM doesn't take more than an amp (probably *much* less), which was the line I was referring to.
Wow! I hadn't considered that aspect of things.. Shows what a luddite I am
Can you please walk me through this?
In the past I ran a dead loss system so a single pole dual throw switch would kill the battery and shut down the igntion. When I was Finally forced to run a alternator I simply bought a kill switch with provisions to protect the alternator.
Now I need to protect the alternator and the ECM.
Frankly I'm having difficulty trying to figure it out..
If you're going to explain it to me, pretend I'm a three year old and only understand colors of wires.
Standard killswitch wiring for Lemons is as follows: Four terminal, (two pole) killswitch. One channel across the battery. This will kill battery power. Another channel on the ignition circuit (The one coming from the ignition key will do the job). If you were ambitious, you could do the same thing at the distributor, or anywhere else in the critical path from power to the spark plugs, but the graceful way to do it is with the ignition line from the ignition switch.
By interrupting the ignition circuit, you kill the spark, which in turn kills the alternator without doing anything that wouldn't happen if you turned the key to the off position. Bottom line the battery isn't supplying power and the alternator isn't supplying power.
My thoughts on the ECM are as follows: Fuckit. Too much work to care about keeping power to its memory circuit. If your car is in the kill position for more than like 5 minutes, it's probably legendarily broken anyway, and forgotten ECM settings aren't going to make anything any worse. If you're paranoid and store the car overnight with the killswitch in the off position, just run it around the paddock to relearn in the morning. If your ECM doesn't keep its memory alive for the few minutes here and there it's killed (tech kill test, and during fueling are the only times it's required to be dead AFAIK), it's probably the LEAST of your problems.
If you still need help wiring that shit up, I once wrote a really patronizing explanation that I'm pretty sure a 5 year old armed with a wiring diagram and screw driver could pull off.
Driver, Pit Monkey, Rod Buster and Engine Fire Starter
Team FinalGear