What does an igniter on an '89 Toyota do?

Have an '89 Toyota Cressida 7MGE engine, the coil mounts on to an igniter. What's the purpose of an igniter, why is it needed when my '66 Ford runs just dandy with just a coil.

Thanks.

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An igniter replaces the points system on in a car with EFI. It takes signals from the computer and using them to turn the power on and off to the coil via a switching transistor. The advantage of this over points is that higher currents can be used to power the coil and this gives a stronger spark.

I bet your 66 Ford has a set of breaker points and a condenser.

The Ignitor is Toyota's term for the electronic ignition module. Replaces the points and condenser.

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Nick Bourne wrote in news:472425c7$1 @dnews.tpgi.com.au:

A electronic igniter has zero to do with EFI.

The igniter replaces the points and condenser on a car that doesn't have points and condenser. Period.

My carbureted '75 Corolla had a semi-electronic transistorized ignition that had BOTH points AND an igniter.

Or an ordinary set of points.

The strength of the spark is IDENTICAL no matter the switching method (points or transistor).

The advantage of electronic switching is LONGEVITY and thus EMISSIONS.

Points that carry full current to the coil (such as installed in a '66 Ford) last about 6,000 miles. By this stage they have worn and degraded enough that the spark weakens, increasing HC emissions, so you need to replace the points.

Toyota's late-'70s combination system (and modern full-electronic systems) use a non-destructible transistor to carry full current to the coil.

The igniter is a switch that allows the ECU to control the ignition timing, rather than mechanical points in the distributor.

That way it can change the timing using it's clever computer powers instead of mechanical/vacuum advance.

Why? Better power and fuel efficiency I suppose.

snipped-for-privacy@hotmail.com wrote in news:1193616539.088912.199010 @z24g2000prh.googlegroups.com:

Wrong.

Wrong.

Wrong.

It's basically right, in a "Big Book of How Things Work" sort of way. One basic generality that was left out is that Toyota and others who employ the ignition module design do so to reduce current flow inside the ECM, among other reasons of less importance. An igniter isn't

*necessary* for the OP's reason given above, but it is a key component in the whole ECM controlled ignition timing to eliminate wear items thing.

By "it" he means the ECM.

It's wrong that he supposes that?

Toyota MDT in MO

Toyota calls it an igniter even for my 1986, which has its timing is controlled mechanically and by a couple of vacuum hoses, with no computer involved:

Actually the diagram is for the California version, not the federal version I have.

What's the relationship between the signal the distributor provides, the ignitor, ECM and coil?

For a complete understanding, you probably would have take a several of Toyota's technician classes, but basically...

The coil steps up voltage from 12 volts to thousands of volts to provide a hot enough spark to ignite the air/fuel mixture.

The ECM has taken on more functions as technology improved, but for the OP's car, it's main purpose was to deliver the proper air/fuel mixture to the engine.

The distributor distributes high voltage current from the coil to the correct cylinder.

Distributors used to have lobes on the distributor shaft, and as the shaft turned, a block which rode on the lobes opened and closed points. As the points closed, the coil's primary circuit was completed, and the coil sent high voltage to the center terminal in the distributor cap, and the rotor sent the current to the correct tower in the distributor cap. Ignition points and the block which rode on the lobes wore fairly rapidly and required periodic replacement to function properly. These early systems did not have an ECM.

The next development was point-less distributors. Instead of a block physically riding on the lobes on the distributor shaft, a sensor (basically a magnet) sent a signal whenever the lobe or a fin passed by the sensor. The voltages from the signal from the sensor are not high enough to trigger the coil, so it goes through the igniter, which "translates" the signal from the sensor to voltages high enough for the coil's primary circuit.

Sorry mate but that's how his 7MGE engine works.

Comboverfish wrote in news: snipped-for-privacy@k79g2000hse.googlegroups.com:

I was going on the assumption that timing was controlled by the ECU using the crank position sensor as its guide.

It didn't make sense to me that the igniter should control the ECU rather than the ECU controlling the igniter.

I thought by "it" he meant the igniter.

It was my understanding that the whole idea behind electronic ignition was to comply with emissions laws, not to make more power. Kettering breaker points do wear out awfully fast.

You know way more than I do, of course. So if I'm wrong, I'm wrong.

True, but the big degradation with point wear (actually, the wear of the rubbing block), was a change in timing. I think it was that a 2 percent change in dwell gave a 1 percent change in timing or vis versa. Timing is critical to emissions, so the breakerless ignition WAS necessary to meet emissions laws that required the engine to meet the limits not only when new, but 50,000 miles later!

Just before the switch I had a Mercury Capri (actually a rebadged German Ford). The rubbing block area was too small and I had to retime or regap the thing every few thousand miles! Nice car otherwise.

Don Stauffer in Minnesota wrote in news: snipped-for-privacy@d55g2000hsg.googlegroups.com:

And if the rubbing block wore, that would close up the gap, resulting in a smaller/weaker spark, no?

The distributor provides a low voltage, low current signal to the ECM that indicates the crankshaft position.

The ECM provides a low voltage, low current signal to the ignition module indicating when to spark.

The ignition module in most cases just acts like a very fast relay, providing a low voltage high current pulse to the coil. It has some stuff in there to control pulse width and get very fast risetime too.

And of course the coil takes the low voltage high current signal from the module and produces a high voltage low current signal. The coil is optimized for fast risetime pulses, and the better controlled the waveform going into it, the more efficient it'll be.

--scott

There were a bunch of capacitive discharge ignition systems available in the aftermarket back then. A couple big TO-3 SCRs on the side of a black box with some big photoflash caps in it. They'd run a small trickle of current through the points to trigger the SCR, then provide a nice high current fast-rising pulse to the coil. Your points last almost forever.

As touted in Popular Mechanics back in the seventies....

--scott

Comboverfish wrote in news: snipped-for-privacy@d55g2000hsg.googlegroups.com:

I was a bad boy. I promise not to do it again.