OT: an ignition problem.

[The Natural Philosopher]

I think my peugot motorhome works that way..ad earlier Puntos I think had a stribbie.

[Jethro]

I know some mid 80s to early 90s Fiats used this system (the more powerful Regatas, Cromas, and Stradas) The distributor was just that - no advance/retard mechanism, which was all handled by the ECU, which had a sensor on the crank.

Prior to that, the more primitive electronic ignitions used a hall-effect sensor in the distributor which was tripped by one of 4 points on the shaft. We had a car which would cut out, by the time the owner had got the AA to it (or us, if we were nearby) it would start. Eventually they got so fed up they left it with us. After a few days using it, we had it fail, quickly jumped out, and confirmed there was no spark. After that it was a case of completely dismantling the ignition system, at which point we discovered the "maintenance free" sensor's wires had become brittle and snapped. At rest they contacted, but when the advance/retard worked, they briefly came apart - hence the stall.

It was indicative of the confidence Fiat had put into the system that it took 2 weeks to order the part. It was also interesting that a few weeks after this happened, a local dealership had a workshop memo, instructing a regular inspect/replace interval for the thing.

You could remove the phrase "with Japanese cars" from that, and it would be just as correct :)

[Dave Plowman (News)]

Think some of the Maestro/Montego range used the same. Given how many problems dizzy caps and rotor arms give it seemed strange not to go the whole hog to twin coils and wasted spark.

[Huge]

Probably saved 17p to keep the dizzy.

[The Natural Philosopher]

I have never had a problem with either.

I had a tracking coil once. That is in fact the sum of all my non contact breaker/capacitor ignition problems on *anything* (except a case of recessed spark plugs where the recesses got full of water)..

[The Natural Philosopher]

A fair bit more than that in the early days - power transistors or triacs were fragile and expensive to do the sorts of 400V needful in either a CD or 'break the coil primary circuit' apps.

With the advent of mains SMPSs and power MOSFETS that's no longer the case.

[thirty-six]

Dealer supplied distributer caps and arms (Lucas) would run about 4 years or 400000 miles without showing significant corrosion. Replacements from a motor factors (CI) would have a lifespan less than half and deterioration in performance would be significant after 2 years. Trying to run them for much longer could lead to a breakdown, although you will have a thousand miles of rough running before it finally cops it. The single coil with distributer was continued with by Rover up to 2000 while other companies struggled with reliability issues of the split coil systems. During the mid 80's when the Naestro/Montego line was introduced, BL (or whatever) where looking to achieve very efficient running cars and the single coil with distributer has the edge. The 1.3 maestro was capable of 55mpg with outstanding acceleration for its size. 3rd gear acceleration from

20mph to 80mph in under 8 seconds, through 1st and 2nd I was able to out-accelerate an XR2 I doubt that would be possible with wasted spark ignition.

[Gib Bogle]

This is all very interesting to me - I didn't realize that distributors had been done away with. I suppose if I look inside the bonnet of our newest car (Toyota Corolla ca. 2006) I'll see that it doesn't have one.

I don't understand why wasted spark ignition should give less power.

[Huge]

I don't believe it, never mind don't understand it.

[Dave Plowman (News)]

No difference whatsoever in performance between 'normal' and wasted spark with both in good condition. But wasted spark dispenses with the dizzy, so is more reliable. The Ford version, EDIS, near bomb proof.

[Dave Plowman (News)]

It doesn't. It's a very common modification - I'm running EDIS on my old Rover, so no more distributor.

[Dave Plowman (News)]

Why? Basically each (identical) coil has two outputs which are identical. They can go to either plug of that pair. So either they're all 'reverse polarity' or none are. There is no difference in the spark polarity or whatever intrinsic to wasted spark - indeed plenty motorbike engines used a conventional points system to achieve this As did the 2CV.

Where on earth did you get that from?

Modern engines use fancy plugs for a long life. Near 100,000 miles isn't uncommon. But the original basic design will work just fine with wasted spark, although EDIS is designed to use plugs with resistors built in.

Of course the ignition is mapped by the ECU. You can produce any spark timing you want using this - unlike a mechanical system which is constrained by springs and bob weights. Which often don't work well when new let alone after some miles and a bit of wear.

[Gib Bogle]

I was being polite (for a change).

[thirty-six]

Are you sure on that, because as I see it under the description you give, the coil with the lower loading, which would be the cylinder not under compression would spark and soak off all the flux energy, while the compressed gas gave a resistance to sparking.

A three cylinder engine, yes that would truly be wasted.

Reversing the polarity of the low tension on an ignition coil and examining the sparking electrodes, the tip becomes pitted, evident after a few hundred miles.

That same mileage can be got from standard plugs with greater energy dispersion and a more efficient and faster combustion giving improved fuel economy and more torque.

Erratic behaviour spuriously associated with mechanical advance is ill- founded. The faults leading to poor engine response may be disguised by electronic mapping. Electronic mapping may well be used to follow an imposed torque response to smooth out a poor engine (or other reasons), rather than let the well-built engine develop full torque and efficiency at the desired level. This disguises developing engine faults.

[thirty-six]

Unlike a maintained distributer system which both crash-proof and bomb- proof.

[Man at B&Q]

Perhaps you forgot the sea salt and kelp powder.

MBQ

[The Natural Philosopher]

sure, but why does a wasted spark reverse the polarity on the coils? you mist have no understanding of electricity to say that.

Mere hand waving. There is no evidence to support anything you say whatsoever.

Its sounds akin to gold plated 10Gigahertx braided litz wire speaker cables to me..

in other words not everybody wants the same thing out of an engine. Smoothness, economy and power as well as long service life are all to an extent antithetical.

Golly. even F1 engines have 'fuel save' versus 'overtaking' modes built it,.

So what on earth are you saying that everyone doesn't know already?

Nothing.

>

[The Natural Philosopher]

Like I said the distributor was never the problem but the points and the capacitor were.

Breakerless ignition and electronic advance and retard were huge improvements. Getting rid of the distributor is purely cost saving. At some point the cost of the mechanics of a distributor and the weight were less than the cost of multi-coil multi-transistor setups.

But its no big deal performance wise.

[thirty-six]

That was the design of the systems I studied at BTEC level 4. As far as understand it is inherent in the wasted spark system, of course there may have mbeen changes in the last 8 years which overcome the problem, but it seems it's all been hushed up.

Restricting the engines performance due to smoothing of the torque output by fudging the ignition, reduces the engine's efficiency, meaning lower gears are held longer. This in no way is a fuel save mode.

[thirty-six]

The Ducellier moving contact points removed any problem inherent in the system, that of contact point erosion. Filing the points was redundant, all that was required at service was to run a slip of brown paper over the contacts, check the dwell angle with a simple meter and check the ignition timing hadn't drifted from it's previous setting. Capacitor faults were usually imagined, many ignition circuit problems were due to badly made connections in the vehicle wiring. Just like the charging circuit, it needs someone with a bit of nouse about electrickery, else you'll be changing plugs and points every month of the year.

The Rover/Motorola MEMS (forgot which version) was one such device which did take advantage of gains in engine "tuning" as it did have a significant range of learning to modify the ingnition mapping. A larger throttle plate and a higher pressure fuel rail alongside light modification to the HT cables and plugs and some simple "ratcheting" at the manifold/port junctions would have the vehichles wheelspinning all through second gear if one stamped on the pedal in the dry with standard tyres at any speed. between 8mph and 60mph. Less modification than this gave the 214Si a 60 to 100mph time of about 4 seconds. These are not the capable speeds of factory new machines, but the capabilities of slight attention to detail not possible in a normal production environment. There were reports that the multipoint injection 1.4 K16 was procucing torque figures at between 40 to 50% over the factory official release on the standard Engine management Unit, significantly larger than the 1.6 factory variant.