gullwingmagazine,
There are a number of principles here, and a number of 'gotchas'.
- A single coil (two towers vertical when the connector is at the bottom) should fire cylinders that are 360° apart in the firing order. For example, if your firing order is 18436572, then 1&6, 8&5, 4&7, and 3&2 should be connected to the same coils (they are called 'complimentary cylinders).
- Do not confuse the firing order with the coil terminal numbering.
- Coil A fires 'first' (i.e., correct for cylinder #1), so it should be connected to cylinder #1 (and the complimentary cylinder). It doesn't matter which terminal on a coil goes to which of the two complimentary cylinders (since they both fire, the one on the exhaust stroke using vary little spark energy because of the ionized exhaust gases).
- On a
four cylinder engine, with a firing order of 1342, that means the coil should be connected so that 1&4 are on coil A (left side when connector is at bottom), and 2&3 are connected to coil B (right side). Other firing orders are connected differently. Basically, you connect #1 and the third cylinder in the firing order to coil A, and the second and fourth cylinders in the firing order to coil B.
- On EDIS4, coil A is connected to pin 10 of the EDIS module, coil B is connected to pin 12 of the EDIS module. If these are connected the wrong way around, the coils will fire in a different order, and the spark plug wires will need to be rearranged.
- On a
6 cylinder engine, the coils in a 6 terminal pack fire ABC (left to right with the connector on the bottom). Coil A fires first and should be connected to cyl #1 and its complimentary cylinder. The coil B should be connected to the cylinder that fires after #1, and its complimentary cylinder. the remaining two cylinders should be connected to coil C.
- For example, with a 6 cylinder having a firing order of 123456 (GM 60° V6), you would connect coil A to 1&4, coil B to 2&5, coil C to 3&6.
- On EDIS6, coil A is connected to pin 10 of the EDIS module, coil B is connected to pin 11 of the EDIS module, and coil C is connected to pin 12 of the EDIS module. If these are connected the other way around, the coils will fire in a different order, and the spark plug wires will need to be rearranged.
- On an
eight cylinder engine, the coils fire ABCD (actually ABCDABCDABCD...). So coil A is connected to cylinder #1 and its complimentary cylinder, coil B is connected to the cylinder that fires after cyl #1 (& its compliment), coil C connects to the nex cylinder (...), and coil D connects to the next cyl, and it's compliment. That's all of them.
- On EDIS8, there are two coil packages, with two coil in each package. Coil A is connected to pin 8 of the EDIS module, coil B is connected to pin 9 of the EDIS module. Coil C is connected to pin 11 of the EDIS module, coil D is connected to pin 12 of the EDIS module. You will need this info to figure out which coil pack is A/B and which is C/D. Coils A and C are on the right side of their respective coil packs, with the conector at the bottom, B and D are on the left.
- For example, if your V8 firing order is 18436572 (Chev V8), then 1&6 should be conected to coil A, 8&5 to coil B, 4&7 to coil C, and 3&2 to coil D. Again, it doesn't matter which of the comlimentary cylinders is connected to which of the terminal on the same coil.
- Cylinders may be numbered in different ways, depending on the manufacturer. Inline four cylinders are generally 1234 from 'front' to 'back', with the front being the opposite end from the transmission. Vee and flat engines might be numbered with even numbers in one bank and odd on the other, or they might be numbered down one bank then the other. ALWAYS check in a service manual to be sure.
- Given the number of potential problems (firing order, cylinder numbering, module to coil wiring), the best advice is from James <
http://megasquirt.sourceforge.net/extra ... dware.html>,
"One method is to test on the starter (plugs out.) First mark your crank pulley with where each plug should fire and then strobe each coil tower in turn as you crank the engine to see which one fires. e.g. I was installing MSnEDIS onto a small block Chevy which has 18436572 firing order, so I marked 1 at TDC, 8 at 90 ATDC i.e. a quarter turn anti-clockwise, then 4 at 180 ATDC, then 3 at 270 ATDC. You can just chalk the numbers on roughly. When you have worked out which plug is which connect up the wiring and off you go. Remember that the coil fires a pair of towers, so in my example 1&6, 8&5, 4&7, 3&2 are the pairs."
(I typed this pretty quickly, so there may be an error or two. I will proof read this in a bit and add it to the MS-II EDIS page.)
Lance.
