Primary current is turned on and off by the action of the armature as it revolves past the pickup coil or sensor. As each tooth of the armature nears the pickup coil, it creates a voltage that signals the electronic module to turn off the coil primary current. A timing circuit in the module will turn the current on again after the coil field has collapsed. When the current is off, however, the magnetic field built up in the coil is allowed to collapse, which causes a high voltage in the secondary windings of the coil.
It is now operating on the secondary ignition circuit, which is the same as in a conventional ignition system. Very different from conventional and electronic — coils sit directly on top of the spark plugs, no spark plug wires, and the system is electronic.
The third type of ignition system is the distributorless ignition. The spark plugs are fired directly from the coils. Spark plug timing is controlled by an ignition module and the engine computer. The distributorless ignition system may have one coil per cylinder or one coil for each pair of cylinders. Learn more about quality spark plugs , find your car part , or find where to buy your auto part today.
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Under no circumstances will we be liable for any loss or damage caused by your reliance on any content. Check them out! About Us. Contact Us. Find My Part. Fascinating Piece, Vince! I remember Dad not being happy with his mistake at this time. He had a tank full of high-test totally not necessary for a Chevy the day the car was tuned up.
The Rotor and Cap were exactly that, a little rotor with a metal contact, and a cap with 6 metal contacts in a circle separated by 60 degrees, and the coil wire went in the center…. When it started to fail, it was intermittently weird at first, then it completely died and had to be swapped out.
That was the easy part. Paying for the little metal box was expensive, but it never gave me trouble again. I think it was called an ignition module. As someone a little older I was on up-close and personal terms with my induction timing light and my dwell-tach.
Points and condenser were just something you did every now and then. I was taught that timing to factory spec was a starting place, then the trick was to advance it little by little until you started to get a knock on acceleration, then back it down just a touch. I dusted off those skills in the 90s when I was driving my 68 Chrysler, but then put my equipment away and have not touched it since. So I suppose with my Dad having a tank full of the high octane go go juice at the time, he was then stuck using the good stuff with his car being tuned that way.
My Civic has a turbocharged engine. The owners manual for my 4. I chalked it up to an experiment. Again, the Mustang does not drive differently with high octane, but the Civic seems to run better. In my old-school experience an advance of timing perked up performance. Advance too far and you got a spark knock.
Add higher octane gas and the knock went away and you still had the advanced timing. Knock sensor engines would seem to me to work like this too. I think many of them recommend 93 but say 87 will work. I suspect they run a bit stronger with the 93, as your Civic seems to. It depends. Some do run better , others not. Numerous tests have shown that almost all naturally aspirated cars set up to run 87 do not achieve higher power or efficiency if run on higher octane gas. These cars will definitely achieve higher output and efficiency with 93 than on My Golf will run just fine on 87 an still has plenty of power.
Using Chevron 94 octane it gets better mileage-since 94 contains no ethanol. There is slightly more mid-range torque on I have never had enough road to see if it makes better horsepower. They do have a base Civic with a NA 2. It is night and day different in the medium to high rev range, although mileage seems the same. It also does the with E so it does seem to adjust for the higher octane. I always experimented with this in all my generic cars over the years and it never made a difference to them before.
Well your experience is mainly due to the fact that it is a Ford FFV. In the early days of FFVs the cars had a physical fuel composition sensor.
So Ford and GM figured out how to determine the fuel through the use of the oxygen and knock sensor. Since they now had to deal with monitoring the evap system the computer knows when you add fuel to the tank. So on the FFV vehicles when the computer senses that fuel has been added and it runs the fuel learn strategy. Once it has learned the fuel it stores that inferred Ethanol content and like the early cars adjusts the timing and fuel accordingly.
As for the using higher fuel octane, Paul is correct when he said it depends. For a modern car to take advantage of the higher octane, it needs an advance map that would allow for it to advance the timing further than what is required for 87 octane.
On the contrary, most modern cars that require premium, will now back off the timing if 87 octane is used in its place. I suspect most turbo vehicles today will having timing maps that would allow for more aggressive advance curves with higher octane fuels, which is why many recommend higher octane for better performance. The big advantage of modern electronics controlling the timing advance curve is that it is dynamic to the fuel used, the load on the engine and other conditions.
The ECU can automatically deduce what timing is optimal for those conditions. However, there are obviously built-in limits. If those limits are set for 87 octane, like I suspect most cars that have 87 octane recommended would have, then running 91 will give no significant advantage,.
Old cars with distributors had static timing curves, both with the mechanical and vacuum advance. So if a car was setup for 87 octane, running 91 octane would offer no advantage since the curve will not change to take advantage of the extra octane.
However, you could re-curve the distributor and alter your base timing to take advantage of this higher octane. This is exactly what many old hot rodders did to cars. Not sure that it actually improved fuel economy much but it probably lengthened the time needed between tuneups.
However, it caused him some embarrassment when our car died just a few miles away from my Grandparents we lived about 4 hours away at the time and we had to be picked up….. My Dad blamed the electronic ignition and he reverted back to the standard breaker ignition as long as we had the car after that.
Also would put some of that grease on the distributor lobes, and avoid getting it on the points. Every other tuneup I would file down the point surfaces instead of replacing them…. However, the electronic Ignition ended up being bypassed when shortly after installation upon a trip to our relatives in Pennsylvania, the car stalled out on I81, and we had to be picked up by relatives…turned out the ignition coil went, and my Dad blamed the electronic ignition…. Tried not to put too much grease on the distributor cam lobe lest it go flying off and get into the point contact….
I also had a special narrow point file and the little feeler gages to measure the gap later on…as a Christmas present 40 years ago Dec my Dad got me a Craftsman tool kit, which included these in an ignition tuneup kit..
That Craftsman tool kit was my most useful gift received ever…still the core of my now expanded tool collection; use it all the time not just for cars either. Excellent article, Vince. I well remember aftermarket transistor ignition kits being very popular in the late 60s and through the 70s. How good they were in some cases is another question. I seem to remember my brother and a friend, both of them were electronic buffs, making a system themselves.
Probably not all that hard. I have had a number of cars with conventional point systems, and rarely ever had any issues with them. These were all fairly low-revving engines, and not very fussy. Thanks to your tutelage, I can see why high performance engines had a greater benefit from these early electronic systems.
Many folks have urged me to replace the points in my F with a Pertronix or such, but it has never given me any trouble, and I have heard of these electronic units crapping out.
No thanks! Thanks for the feedback Paul! My wife works in education, so maybe some of her talent has rubbed off on me. I agree with your assessment on your truck. The points are fine. I have run Pertonix and they do seem to improve things a bit, but cost a lot more and can fail without warning. I stick with the points in my old Scouts even though there are a number of options to ditch them. For quick starts on a warm engine nothing beats a carb and a set of points.
The next time the points open it will make a spark. With a variable reluctance, or pulse inductance pickup you need some rpm to generate a strong enough signal to cause the module to trigger the coil.
Throw in fuel modern sequential or direct injection and the engine may need to complete near two revolutions before it has enough information to be able to start making sparks and spraying fuel.
Thought the spark plugs fire when the points close! Looking forward to the next installment. I have a well used dwell meter and timing light buried somewhere in the back of my tool cart. Probably never will again. My days of giving a substantial part of my paycheck to the Snap-On man are long gone. Someday soon the only people left who understand these old technologies will be specialists working on museum pieces. Wonder if any of them will want my tools. Same here regarding the dwell meter and timing light.
Somewhere in the shed, stuffed away in a box, buried under heaps of other stuff. Live long enough and your place becomes a museum of retro-technology! Very informative, I have a car with points ignition it rarely gives any trouble however it is not my daily drive, The only electronic ignition systems I have had trouble with were on Australian cars Ford Holden GM and Chrysler,Reviving them when they fail varies with the make.
Great education for this elderly shade tree mechanic, who has done his share of tune-ups in the pre-transistor era, and has never really understood the newer stuff. Thank you and looking forward to the sequence. Still at it. Installed a new timing belt in my Metro this AM, and a new water pump and inlet pipe yesterday. Only had to swear once! Regarding the ballast resistor and 8V supply, I never heard of a ballast resistor system until the Chrysler Alpine was launched with transistor ignition in I had an aftermarket tansistor conversion on a BMC engine in the mid 70s, and it used add-on parts in the Lucas distributor.
The only issue was that the distributor cap struggled to handle the higher spark voltage — which was also the case with the Alpine. It seemed to improve things, but positively ate plugs, points and distributor caps. Now I think I understand why! The one thing about the resistor wire was that it seemed far less failure prone than the ballast resistor.
Like Paul remembered above, electronic hobbyists were building their own transistor ignitions in the early days. Practically as demanding as military applications. Manufacturers of cars and of transistors found this out the hard way. It took these early applications to literally shake and bake them down to volume production longevity and cost requirements.
Aftermarket capacitive discharge ignitions, switched by breaker points, were briefly popular. They stored energy in a capacitor and that energy was sent through the coil when triggered by the breaker point circuitry.
This resulted in much, MUCH higher voltage of longer duration in the coil primary and thus in the coil secondary and through the spark plug, resulting in s higher-voltage and longer duration spark. Problem was that the high voltage would cause arcing in some original coils, which of course were not built to withstand the higher voltage, and would fail.
I will discus CD ignitions in the next installment. They had their advantages, but ultimately there were better systems for cleaner emissions. They remained popular in the aftermarket for high performance use and are still commonly used today MSD being the most common. Call it 80 thousand miles on each. The Chrysler had the standard factory points set up for about 5 years and then I installed an aftermarket Pertronix electronic replacement that fits inside the distributor.
The electronics enabled more precise timing of the spark for maximum fuel efficiency, power and cleaner emissions. Many engines today have even dispensed with spark plug wires altogether by mounting an ignition coil directly on the spark plug for optimal timing control and power. Looking to the future, spark plugs and compression ignition will probably continue to dominate for some time to come, but we may well see a merging of these two concepts with homogeneous charge compression ignition HCCI.
HCCI engines run on gasoline instead of diesel fuel and can switch back and forth between the two ignition modes depending on driving conditions. HCCI engines have the potential to improve petrol engine efficiency to near diesel levels without the NOx and soot emissions. Unfortunately we probably won't see this next evolutionary step on the road until at least late in the decade.
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