Identifying and Dealing with EMI, searching and searching Options

[McMark]

I would like to spend some serious time doing a qualitative analysis of the EMI that is probably going on in my engine bay. I've been searching Google for some write ups that might help me get started, but everything seems to be quick marketing blurbs for every electronics company on the planet. Does anyone have some links or books or anything that might help me?

Here is how I would like to approach the problem:
1. Evaluate my current situation.
2. Identify the sources.
3. Implement effective corrective measures.
4. Judge the effectiveness of my efforts.

This is probably over the top, but being the son of an engineer makes me think this way. (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

So give me your best links and books regarding identifying and dealing with EMI, please.

[KitCarlson]

Mark, All,

I am back and hope I can be of help. Here are a few details. The KitCarlson EMS draws only 100mA from the supply. No huge wire or special filters needed. A good battery is always required for electronics. A bad or weak battery cell and a mechanical voltage regulator can results spikes and sags. The best ground is at the battery terminal. It avoids problems if the transmission strap is broken (an often neglected part), however you should have a good strap, since the head temperature sensor ground returns there.

The multiple grounds on the EMS are essential, each one takes the driven current to ground on a separate path. This means the ignition coil and injectors each have their own grounds. This is a good thing. It avoids ground loops. Supply for coil and injectors come from the same places as in the orignial D-jet, sorry, no magic, no free energy for CA. The improved injector system differs in the drive system (sinking instead of sourcing), but that is a long story. The good part is it avoids the grounds on the engine that get dirty and are hard to find buried under the intake.

hmmm...
I think your problem is with spark plug wires. The system is direct fire so you can pull the plug wires on #1 and #3 , leave connected to the coil. Measure continuity end to end it should be 15K to 20K ohms. Repeat with #2 and #4. If you measure "open" you have a break at plug terminal connection and are making a huge spark in a bad place! This will lead to missing and running like c#ap. Recently found this on another test unit on a Turbo engine.

Do not use solid wires! However, I have used them in development without problem. It works because of the resistance in the coil and plug ends. The solid wire radiates much more than carbon wires. No use making things more difficult.

Also the layout of the harness wires and plug wires is important. Avoid close proximity of the plug wires and the harness wires. There is a current loop from ground to plug #1 to the coil out the coil to plug #3 then to ground. Same for the #2 and #4 loop. Placing harness wires under the spark plug wires puts them inside the loop and couples energy. A transformer....

An example of bad is placing the injector harness on the engine tin with the plug wires looping over them. They should be outside the plug wire loop, a very simple change with a huge diffence. Don't worry if you do not understand this.

The real solution is for me to write a good install manual with pictures showing routing prior to going to market. I am just finding not everyone thinks like me, thinking about current loops and mutual coupling for every wire connection.

Please snap some pictures with the aircleaner off showing wiring I might see some fixes.

Dave
aka KitCarlson