ignition condenser - revisited

"As the condenser gets saturated, current flow stops,
at which point the field collapses and a spark is generated at the
plugs."

Just to add: after current flow stops, it reverses, as the capacitor
and coil act as a damped ocsillator, dissapating the energy from the
stored charge as heat, until the points close again.

 

So it's a radio noise condensor, not a Kettering condenser.

That makes sense for its location. In a Kettering system, if the radio
suppressor was installed on the other side of the coil, you'd suffer
accelerated points burning.

Nope. Nothing at all. But...I do replace the cap gasket every time the cap
is off, just in case the old one might allow moisture to enter once its
original seal is brken.

 

Yes.

My wording above (re being in parallel) is misleading, as you probably
figured out. I won't try to clear it up, since it's not entirely wrong, but
instead will just say that to which side of the coil the condenser connects
is the telling point, as you also seem to have picked up on.

I agree that (1) certainly the Kettering points wouldn't be protected in the
same way; and (2) the key identifier of what purpose the condenser serves
here is to what side (+ or -) of the coil the capacitor attaches.

I did find that this radio noise condenser is used only on 1991 and earlier
ignition systems. The UK site drawings support this. Also, my 1985-1995
Civic Chilton's explicitly states that starting in 1992 the radio noise
condenser was "built into" the igniter. The 1995+ Civic ignition system
schematics at the UK site indicate this around the igniter icon as well.

This, along with some more commentary I found, leads me to believe that this
"radio noise condenser" minimizes radio frequency noise that may disrupt not
only the car radio's operation, but also as importantly the igniter's
transistors /and/ the car's ECU. The ECU as your site and others show of
course is part of what causes the igniter's transistors to "fire" and so has
input to the igniter.

I see Kevin McMurtrie on May 30th said as much, re the flyback voltage to
the ignitor being a concern, in his comments about your site.

I have been accessing your ignitor site a lot, by the way. I am not finding
anything deficient in it, other than maybe some mention of this radio noise
condenser is due. 'Cause I think Jim is onto something big here, at least
for older Hondas.

I changed my new ignition system/radio noise condenser site a bit to reflect
the above information. http://home.earthlink.net/~honda.lioness/id5.html


I am still puzzled as to why the 1991 CRX distributor Jim put into his 1989
Civic has no condenser (so he says); yet the Civic then worked perfectly. I
would guess whatever distributor he popped into the Civic that worked so
well has an ignitor with an internal condenser, and so the igniter is from
1992 or later.

Or maybe some of these igniter's with internal radio noise condensers got
into the 1991's.

I'm seeing on the net that any ol' Autozone should have these capacitors.

Huh. I am not inclined to buy the low temperature climate argument Jim
proposes (though he could be right and this certainly at least may help).
Mostly because I lived up that way and wasn't spared igniter problems. (But
maybe my 91 Civic's first igniter failure in 1997 was due to the defect that
was recalled? Regardless, I sure as heck wasn't using OEM then the way I am
today, and may very well have overlooked timely spark plug and wire
maintenance as well.) I would reckon it's your having been very careful with
the plugs and wires.

Spooky, to me (but I mean that in a nice way). You never touched your 91
Teg's PCV valve until a year or so ago, and it was still extraordinarily
clean, too.

It seems you take amazing care of your wheels!

 

Maybe. But I'd like to see some more info about why that part would have
such an effect, when all it seems to do is keep switching noise from
backing upstream, just like the same part used to on Kettering systems.

It sort of makes sense, because heat is a known life-limiting factor for
electronics.

You also don't know for sure what kind of treatment your car had before you
bought it, which is a problem with any used car.

Possible, but I think the bad igniters were all the the '90s. If yours is a
late '91, chances are good it was not in the recall.

Oil changes every 3K miles/2 months or less ever since the first change in
1991.

I really do believe it's been simple maintenance that has resulted in the
reliability and durability. Nothing special, just steady maintenance from
Day 1.

 

You are talking about a condenser different from the one in parallel with
the points on a Kettering system, aren't you? So you're saying the Kettering
has (1) the condenser in parallel with the points, and connected to the -
side of the coil; and (2) a condenser connected to the + side of the coil?

Which seems reasonable to me. There are other devices used to minimize
engine noise affecting electrical systems, as I guess you know.

Kettering condenser (2) would presumably electrically protect only the car
radio.

I copied your five years for rotor, caps, and wires/one or two years for
plugs into my notes and will start using this interval. Though I will
probably always check the resistance of the wires when I change the plugs.
Also, I'm going to clean out the distributor cap with every plug change.

 

Elle wrote:

Condenser (2) is nothing to do with the Kettering ignition system.
The Kettering system works perfectly well without (2). Kettering
nor anyone else advocates (2) as a requirement or improvement
to Kettering ignition systems in regard to ignition performance.

(2) serves only to try to prevent high frequency transients from
backing up the wiring and interfering with other equipment
running in the vehicle - GPS, AM/FM radio, Cassette player,
mobile phone, etc., etc., etc.

So please stop referring to (2) as a Kettering component - it isn't
and has never been so. I need to refute the reference to (2) being
a part of a Kettering system for the sake of the public record.

 

Read the context. I was asking Tegger if he was proposing that there might
be a second condenser in an ignition system that uses Kettering points yada.
I didn't know a better way to make a distinction.

It's not easy discussing this without everyone sitting at a table and
pointing to schematics as s/he talks. So play nice. Or don't. <shrug>

 

My 1968 VW bug had 2 capacitors in the ignition system.
The first was the standard points capacitor, or to use a term
that makes the engineer in me cringe, condenser. The second
was across the primary, for RFI (radio frequency interfence)
reduction. Remove the one across the coil and the AM radio
was useless.

My 1974 Honda CB350, dual ignition system, one for each cylinder,
had a cap across each set of points and a big one across the
junction of the coils from +12 to ground. And if you disconnected
the center one you got sparks from both sides at "once". Slight
timing differences prevented the motorcycle form running very
well, a lot of back fires etc. I found this out the hard way
one night in a nature preserve when the quick connect, disconnected
just as quickly. Hard to find in the dark. I was rathr amazed at
much difference that little cap made.

As my hobby is short wave listening I have learned more then a
little about how to quiten noisey electrical systems.

Terry

 

Ha. I was cussing once I realized Jim meant a capacitor.

Then I cussed myself out, because for this application, I learned that
capacitors are still commonly referred to as condensers. Academic
engineering can only take a person so far. Sometimes it's not far at all.

I took my distributor off today, mostly to clean out an accumulation of
oily-grime from other, past problems underneath, but also to find this
capacitor (condenser), photograph it, and put something I thought was so
darn profound (especially after reading your tests, which tend to support
Jim's findings) on my web site. I swear my 91 Civic hasn't an external one.

Whether its igniter has a built-in one is something I will continue to
research. Maybe the manuals aren't accurate when they say it was 1992 when
the capacitors became "built-in" to the igniter.

 

To add to this: I finally got the old igniter apart. It is actually the
second igniter used in the car, and it was originally installed by Firestone
after the first igniter failed. One thing leapt out at me once I had it
apart. Could anyone tell me what the part is that I have circled at the
photo at site http://home.earthlink.net/~honda.lioness/id8.html .

The drawings at Tegger's igniter site
http://www.tegger.com/hondafaq/igniter-operation/index.html
do not appear to have this part. So I'm thinking the part above is the
"built-in radio condenser." If so, it helps support the contention that the
manuals are mistaken.

 

while you do get color coded capacitors, it's /much/ more common for
their value to be printed in numerals. last time i looked anyway.
resistors otoh, color coding is their primary distinguishing feature.
can't really say which is which without a clearer pic.

 

I'll try to get a better photo up tomorrow. I can't nail it down using the
net, though it does seem that it bears a closer resemblance to the resistors
I see from googling, similar to your impression.

It seems large compared to everything else in the igniter. Plus it's absent
from Tegger's and Graham's sites' photos as well.

But I don't know. Seems like the guts of these things can vary a fair amount
and still accomplish the same thing.

 

Jim and anyone else interested in electronics: I put up a drawing of the
(igniter guts) part in question at
http://home.earthlink.net/~honda.lioness/id8.html . Also, I did some
continuity tests (doh, should have done these first thing). The part itself
fails a continuity test. So there's no way it can be a resistor, right?

There is continuity between
(1) the top wire of the part and the igniter's terminal T4 (= tachometer
input);
and
(2) the bottom wire of the part and the igniter's terminal T3 ( = terminal B
of the ignition coil)


So if it's a "built-in radio noise condenser," then it is electrically
located in a different position from the external radio noise condensers on
other Honda models.

But I dunno... Just trying to learn more electronics.

 

Shoot. Post-o. Corrections are inserted below.

 

that drawing is /classic/ resistor. gold band = 5% tolerance. 2.2k
ohm. also, i would not expect it to be between tach & coil. if it were
a capacitor, i'd expect it between 2 & 3, or 3 & ground. don't forget,
a lot of those grey rectangles on the circuit board are on-board capacitors.

 

capacitors.

I hear you.

Is there any earthly reason why it would fail a continuity test, though?

The igniter from which it came was working when it was removed
(pre-emptively) two years ago.

I am aware that a number of the squares are capacitors, per Graham's site.
"Biscuit colored" is the way I think he described their color.

Also of perhaps some note: This part's leads are easily accessible with a
multimeter's probes. All the other ignitor parts are under a coating of
clear plastic. It's like over five times the size of any of the capacitors
and resistors under the plastic.

 

Doh, yours truly just measured the resistance of the part in place. I
presume I am getting the resistance of the part and not some other circuit
connected via these two points.

Rounded to two significant digits, it reads 2.2 k ohms.

Still wondering about why it fails the continuity test, though. What am I
missing?

 

Not exactly! It is a 2,200 Ohms 5% 0.5 Watt film resistor if you have
related the band colors correctly and the third 'red' isn't orange.
(I don't mean the background color you used in the graphic.)

It replaces the long dark green/black rectangular printed resistor in
my photo which runs from the transistor output at the top (just
underneath the 'HUCO' legend) and the T1 terminal. It probably isn't
faulty but you'll need to set your meter to a range which expects to be
able to read 2,200 Ohms, probably the 20,000 Ohms range.

The resistor only feeds the tachometer instrument with pulses from the
distributor and since it is connected to the output of the igniter, it
cannot be the supressor you seek.

How right you are!

 

you mean the audible continuity test on a dvm? it's usually for testing
wire, so it won't work if resistance is more than a few ohms.

 

Okay. Thank you.