Tonight I started working on the output section. Heres a couple of decent pictures of so far.





I started at step 56, when you get to step 59 Do not install D8 in the center of the picture, Due to running a PWM idle control valve.



When you reach Step 62 do not install Q4 Idle control transistor as this cannot handle the bosch idle control valve, This Transistor is replaced by the one in the PWM idle Mod kit.

I found I could mount the PWM transistor in the R37 location on the heatsink bar. Follow the insructions for PWM users below step 62. Solder the supplied wires from Q4 to the upgraded transistor. Remember not to install Q20 and D8.



Jumper R39 with wire instead of fitting the resistor.

Remember step 63 and 64

Thats the PWM Idle control finished. This took me a while to work out as I was a bit confused but it all made sense in the end

Step 65

Now is where it gets hard, Well I did for me as I was very confused with the coil driving circuits that come next.

The way we wish to drive the coils/engine is called wasted spark. (Same as the way the coils are originally triggered)

Wasted Spark: This is used on a lot of 4 stroke engines and is where a pair of cylinders are fired together, one cylinder is on the compression stroke and the other on the exhaust stroke. The 2 cylinders that are fired are the pair that move together and are therefore opposite each other in the firing order. This setup therefore has multiple coils, usually 2 for a 4cy, 4 for a 8cy, etc. It does NOT have a distributor, as the spark plugs in the cylinders are connected directly to the coils.

E.g.

Fiat 4 cylinder firing order = 1, 3, 4, 2 This would be 2 rotations of the crank, so 720 degs.
To fire this engine in wasted spark we would fire 1+4 together (as these are opposite in the firing order), then 180deg later we would fire 3+2 (again these are opposite in the firing order), this repeats every crank revolution.

The cylinder that is fired on it's exhaust stroke is know as the "wasted spark" as it produces no power. The benefits are that the coil fires less often than when using a single coil and has more time to charge ready for its next spark. This is very helpful at high revs when the charge time can be very small.

The fiat coil pack as far as I know is 4 coils, now to use this we need two coil drivers, one to fire a pair of coils for 1+4 and then another driver to fire the second pair of coils for 2+3 (Looking at the wiring diagrams today the coil pack is 2 coils, one for 1+2 and one for 2+3)

To build this section I used a link I was sent by DIY Autotune. I had to email them as I got totally lost, everything I'm typing now I learned last night, Lol.

This Is the link
http://www.msextra.com/manuals/MS_Ex...nual.htm#2coil

I have detailed what I did in my next post.