My distributor went, and while shopping around for another one, I happened upon companies offering competition ignitions, that claimed to offer better gas mileage as well. These were companies like MSD (MDS 6a ignition) and ACCEL, Procomp. These systems boosted the spark power by over 25%, offered a multispark feature, and some claimed to use less power, while claiming improved performance and mileage. They cost between $100 & $300 bucks dependent upon whether or not the distributor cap, coil, and ignition control module are all replaced. While an RPM limiting feature is beyond my needs now, I'm otherwise a newbie in a sea of statistics and performance claims with these ignition options. Never mind the finer points of installing all of the hardware that was once inside the distributor cap, someplace else. Articles, and ideas?
I used to have a MSD digital 6+ ignition box along with the Blaster SS coil and other MSD stuff. Let me tell you the stock stuff for the car is better, unless you're going for hp. The MSD system didn't give me no mileage increase. In fact I'm on the stock oem nissan system now. I only used the MSD stuff so I can run a higher shot of nitrous.
I've sold the whole system to some joker that ripped me off. Sucks for him because I had to get some custom parts fabricated. Once the part dies which it will since it's only good for 30k. I will be enjoying him suffer trying to make the same part.
I installed a MSD 6a on my truck almost 2 years ago, along with Accel cap/roter, taylor wires and some platinum plugs (all recommended by my trusted mechanic). I have had no problems with the system, and have noticed improvements. Most of the improvements came in smoothness though, idle, acceleration, but i don't think i've seen much of an MPG boost if any. I was interested to see what the emissions would be before/after but i just moved to a place that doesn't require an emissions test, so the world may never know.
When I first got into engine management and was doing a lot of reading, I found this good site that talked about aftermarket ignitions, and how, unless there were really specific circumstances, they wou;dn't do anything. I've looked for the link, but couldn't find it. I'll try again in a bit.
I saw the same results in smoothness and a little bit more power with the MSD, but no mpg improvement. At 2750rpm the MSD system really started showing the difference between it and stock. But once I got to 4000rpm it would kill my top end like stock. I did find a way to get my power up top. When my timing was 13 degrees instead of 20 my car accelarated a lot faster 4000-6100rpm. It's not a butt dyno. I saw my tech move 2 times faster in that rpm range.
The only reason I bought the MSD 6A was so that I could ditch my stock ICM and run a home made one. I also noticed a smoother idle and less breaking up near the top end of the RPM range.
I'm no EE, but I know that the stock ignition system on a honda is induction based and the MSD system is capacitance based - this is supposed to help the thing fire a spark more reliably at high RPM's from what I've heard. Also, the multiple spark discharge below 3K RPM's - but I only used this on my turbocharged Civic, not exactly a gas mileage queen.
Tried the MSD5 Ignition on my stock truck and found no improvement. Did use the Jacobs Omni Ignition on a 1979 Cadillac and 1981 Cadillac for about five years before I sold it. Highly recommend it. Found both a power increase and mileage improvement of about 2 mpg. Didn't keep logs back then but I remember the mpg improvement. Costed about three hundred dollars with spark plug wires. Plugs right into the existing wiring harness with no cutting or splicing. Engine ran smooth and the spark that the ignition would generate was impressive to say the least. Came with detailed instructions and recommended using the stock spark plugs gapped at .010 greater than factory recommendation. I remember the instructions saying not to use any aftermarket spark plugs, (Platinum, split fire, etc.) as the spark it generates would melt the electrodes.
Found a set of "performance" spark plug wires by American Products Company, which were more than %50 off, on ebay. We'll find out if there was a reason for why they were more than %50 off Friday morning. 9.3mm silicone, magnetic tunnel, cheaper than an MSD ignition!