What does an igniter on an '89 Toyota do?

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

Is this also what happens with Honda igniters and the "ignition output" signal wire?

I had somebody tell me once that the Honda igniter itself controls dwell by sensing back EMF from the coil as it charges up. When the EMF reaches a certain level, the igniter cuts current on its own. Is this true?

...and successfully used in my treasured 1960 Pontiac.

innews: snipped-for-privacy@d55g2000hsg.googlegroups.com:

Yes, the Yellow/Green wire (Accord) or White wire (Civic) (or whatever color on whatever other models) ignition circuit is similar. It is used to confirm a firing event. I am not intimately familiar with this system, but I assume that the ECM produces a bias voltage on that wire, and the igniter modifies said voltage once for every secondary collapse. Code 15 on OBDI Hondas signals a failure related to this circuit or the functions it monitors.

The igniter could very well control it's own dwell parameter but I don't know. That's getting into multichannel scope and lots of free time territory. You may want to Google using some permutatuin of the following phrases: honda ignition system outline "motor magazine" "import service". Every few years one of the major trade mags will write another article on common ignition systems such as the 90's PGM- FI setup. I know that Motor Mag is available online for free and includes pdfs of their back issue articles.

Toyota MDT in MO

By the time the domestics were into electronic ignition, the Japanese cars were behind the curve and stayed there for almost a decade. What you describe is a weird hybrid. I guess they saved $$ on a magnetic triggering device (woo hoo!) but still stuck you with points (d'oh!). The points probably wore more in the rubbing block than the contacts due to the much reduced current and high voltage arcing through said contacts. I guess that's an improvement.

Toyota MDT in MO

No. Smaller point gap equals longer dwell, longer dwell equals more time to saturate the coil.

I bought one for my VW Rabbit, which was supposed to be a modern car for its time (FWD, port fuel injection) but had manual brake adjusters and point ignition. The pair of TO-3s on top were transistors that drove the inverter transformer, while the SCR was a small TO-5 inside. I couldn't get distributor caps to last more than a few weeks with it before they cracked and formed carbon tracks, and the ignition wires measured infinite ohms because the resistors in the spark plug boots cracked (VW didn't use resistor wire). That was solved by adding some zeners to the CD transformer's secondary to limit the voltage to the coil.

These CDs needed only a tiny amount of current through the points, but they deliberately fed them about 250 mA to burn off oily deposits.

I bought one for my VW Rabbit, which was supposed to be a modern car for its time (FWD, port fuel injection) but had manual brake adjusters and point ignition. The pair of TO-3s on top were transistors that drove the inverter transformer, while the SCR was a small TO-5 inside. I couldn't get distributor caps to last more than a few weeks with it before they cracked and formed carbon tracks, and the ignition wires measured infinite ohms because the resistors in the spark plug boots cracked (VW didn't use resistor wire). That was solved by adding some zeners to the CD transformer's secondary to limit the voltage to the coil.

These CDs needed only a tiny amount of current through the points, but they deliberately fed them about 250 mA to burn off oily deposits.

The impedance is lower with electronic switching, at least at the very start of the ignition pulse. Coils made for point ignition typically have higher resistance, especially on the secondary.

Even National's "non-destructible" LM395 transistor substitutes aren't indestructible. Are you sure ignition transistors don't have a zener and capacitor across them for protection?

The impedance is lower with electronic switching, at least at the very start of the ignition pulse. Coils made for point ignition typically have higher resistance, especially on the secondary.

Even National's "non-destructible" LM395 transistor substitutes aren't indestructible. Are you sure ignition transistors don't have a zener and capacitor across them for protection?

But your Ford has points and condensor. Points are a switch to turn on and off the feild coil. Now its done electonically wiht a transisitor, which is controleld by a small computer which gets the signal when to collapse the feild from a small AC signal coming from the pick up coil.

Ignitor is a way to electronically control feild coil. It doesnt have to communicate with the ECU (pre TCCS systmes never comunicated with the ECM, advance was mechanical and vacuum) but the newer units, TCCS do communicate witht he ECU (IGt and IGf) to control timing, thus, no more need for mechanical or vacuum advance. TCCS showed up in around 1985ish.

Scott, Toyota actually had what they called a "semi electronic" ignition system. I know it was in 1977, it was only a few years. It still had points, but it was a millivolt signal (used just as a switch) to trigger the coil electronically, not sure if it was silicone controlled rectifiers as mentioned above or just a transistor, but the same principle. Points would last forever. But the points fo rthis year wasnmt the tungsten ones, so they would bolt in a point ignition system, but wouldnt last long.

Thats the one! I think 1977 was the last year TeGGeR.

"toyota_mdt_tech" ;D

Neil Nelson wrote in news:nonelson- snipped-for-privacy@news.mil.sbcglobal.net:

Right you are. Brain cramp on my part. I was thinking of it backwards.

If the rubbing block wears down, the cam would not push the points apart as far, or as soon, so you'd get excessive dwell and a late spark.

Comboverfish wrote in news: snipped-for-privacy@o38g2000hse.googlegroups.com:

I'm not quite getting the "bias voltage" modification thing.

As I understand it fron Googling, the ECM would put, for instance, +5VDC on the monitor line (which implies some kind of permanent ground in the igniter). The igniter would change that to -5VDC on a firing impulse.

Why wouldn't there simply be NO voltage on the monitor line until the igniter put voltage of some type there? What is the advantage of modifying a pre-existing voltage instead of just creating voltage where there was none before?

I'm sure I could buy that info straight from Honda's Techinfo site, but all their training materials are like $50-$60 each for non-dealers.

Thanks. Trade magazines can be amazing sources for information. I didn't know about Motor magazine until your post.

Unfortunately there's no article search, so you have to go through every issue one by one, which is slow work. But then so is wading through Click and Clack's archive at

Also Motor online does not reproduce any diagrams or photographs that appeared in the original print article.

Thanks again. Lots of reading for me.

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

It's been my observation that the Japanese do little that is new. They usually seem to copy what others are doing, but try to improve on it where they can.

Strangely, I remember the point gap didn't change much over the life of the points. Maybe a couple of thou. If there was significant rubbing block wear, I didn't notice it.

You got a bit of a black spot where the points touched, but it was nothing like the little peak and crater you had with a Kettering system over the course of 6,000 miles.

I had big problems with the igniter itself. Over the course of five years and 50K miles, I had two igniters fail on me. It surely had to do with the fact that I live in the Rust Belt, and the igniter was installed immediately behind the right-side headlight, where it was bathed in salt water every winter. The horn relay was bolted to the same bracket, and caused a few very embarrassing moments.

Then there were the seize-o-matic front brakes, the windshield washer reservoir that held about a pint and was located at the firewall and had a fill opening the size of a nickel... Those cars were NOT made for north-eastern winters.

Liberals are the scourge of society wrote in news:2Y-dnRrAdqYHqbTanZ2dnUVZ snipped-for-privacy@comcast.com:

The diagram in my Haynes shop manual from 1981 shows a transistor.

" snipped-for-privacy@mail.com" wrote in news: snipped-for-privacy@k35g2000prh.googlegroups.com:

Interesting information. I didn't know that.

But I suspect any benefit from lower impedance is just a bonus, not the primary reason for using electronic switching instead of mechanical switching.

I meant "non-destructible" in a relative sense. Transistors are not considered consumables the way Kettering points are.

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