Ignition cut-out
Michael Pardee
suffered a short bout of engine failure. She described it as surging a
couple times when she tried to accelerate, then the engine died when she
braked. I quizzed her about the tach and she was clear it was jumping rather
than swinging with the engine. It didn't start right away, but would sputter
occasionally and eventually lit off as though flooded (which it probably was
by then).
The Main Relay and ignitor are each about a year old (but both are NAPA
aftermarket, since the car insists on breaking down on Sundays and
holidays). The timing belt is 4 years, 60K miles old. My son and I replaced
the radiator about 2 weeks ago, so I am wondering if we stirred up evil
spirits in the process of that. He bled the system carefully, but a leak in
the lower radiator hose attachment may have let air in. I haven't done a
visual inspection yet, but will in the morning.
What comes to mind? Ignition switch? Some particular underhood wiring?
Distributor? Something I'm forgetting? She is committed to driving to San
Diego in a week or so and I'd sure like to sort this out by then.
TIA
Mike
Elle
I'd try to do a check of it early on. Dying when
braking--then being able to restart it after a cooldown
period, at least until the coil fails completely--is a
symptom.
I know you have a lot of experience with Hondas. This is
just where I'd start, based on the car's age and symptoms.
"Michael Pardee" <michae...@cybertrails.com> wrote
Michael Pardee
news:J8qrf.9529$3Z....@newsread1.news.atl.earthlink.net...
> How old's the ignition coil?
>
> I'd try to do a check of it early on. Dying when
> braking--then being able to restart it after a cooldown
> period, at least until the coil fails completely--is a
> symptom.
>
> I know you have a lot of experience with Hondas. This is
> just where I'd start, based on the car's age and symptoms.
>
shotgun it out, whether or not I find something else wrong. I should even
have time to get an OEM part before she leaves. At least that is something I
don't have to worry about disturbing unnecessarily - I hate doing invasive
work so soon before a big trip. Thanks, Elle!
Mike
Remco
I wonder if the problem is electrical in nature, because the RPMs were
jumping around wildly.
Since the tach and engine timing both get their signal from the crank
sensor, I'd also look in that area.
Remco
High Tech Misfit
> I wonder if the problem is electrical in nature, because the RPMs were
> jumping around wildly.
>
> Since the tach and engine timing both get their signal from the crank
> sensor, I'd also look in that area.
I thought I read on here recently that an erratic tach that precedes a
cut-out is a sign of a bad igniter.
Remco
Not sure about any previous post on this issue, but the ignitor seems
to just be a larger power transistor (probably a darlington, but that's
besides a point).
The way this transistor is configured, it simply acts as a switch that
that closes/opens a contact when its input changes states (to simplify
it all, imagine a relay with a coil and contact - that is not quite
what a transistor is, but behaves quite similarly the way an ignitor is
hooked up).
When a level is applied to its input, it switches the primary side (the
12V side, basically) of the coil to ground and does this at a very high
rate of speed. The secondary of the coil is what generates a high
voltage spark.
The output of the ignitor does not seem to attach to anything else so
iti it breaks you won't have spark.
I don't think the tach is getting its signal from the ignitor, so don't
see how one can tell by the tach that the ignitor is bad. If you
somehow can detect this on the tach, it must be some sort of weird
artifact.
Remco
Michael Pardee
news:1135557540.2...@g43g2000cwa.googlegroups.com...
igniter. The current symptoms do sound like igniter trouble, but the igniter
(and tune-up parts) are a little less than a year old... from March, IIRC. I
might be wise to re-heatsink the igniter, though.
What makes me think it isn't distributor sensor trouble is that there is no
"check engine" light, suggesting the problem is past the ECU... i.e. igniter
or coil, or high tension side (like the rotor or cap.)
Mike
Elle
> Actually, I believe the tach does get its signal from a
separate lead on the
> igniter.
The electrical diagram for the ignition system suggests you
are remembering correctly. See the top schematic at
http://home.earthlink.net/~honda.lioness/id5.html . Tegger's
version appears to confirm it:
http://www.tegger.com/hondafaq/igniter-operation/index.html
> The current symptoms do sound like igniter trouble, but
the igniter
> (and tune-up parts) are a little less than a year old...
from March, IIRC. I
> might be wise to re-heatsink the igniter, though.
>
> What makes me think it isn't distributor sensor trouble is
that there is no
> "check engine" light, suggesting the problem is past the
ECU... i.e. igniter
> or coil, or high tension side (like the rotor or cap.)
Plus ISTM igniters don't exactly seem to die slowly, at
least not the way coils often do. Igniters seem more like an
all-or-nothing deal, with symptoms only for the very
observant, at best.
Michael Pardee
by Wednesday. Since there really is no way to determine whether the coil is
failing intermittently and 225K miles is a lot of service to expect from
one, it seemed like the prudent thing to do. I can check the ignition switch
by seeing if the voltage across it fluctuates from one time to the next, but
the coil keeps its secrets.
In my experience, the more power a device handles the more likely it is to
have a limited life. An ignition coil has to transform hefty currents into
hefty high voltage jolts, so I don't expect it to last forever. Thanks again
for the suggestion.
Mike
Remco
> "Michael Pardee" <michae...@cybertrails.com> wrote
> > Actually, I believe the tach does get its signal from a
> separate lead on the
> > igniter.
>
> The electrical diagram for the ignition system suggests you
> are remembering correctly. See the top schematic at
> http://home.earthlink.net/~honda.lioness/id5.html . Tegger's
> version appears to confirm it:
> http://www.tegger.com/hondafaq/igniter-operation/index.html
>
You're absolutely right - I stand corrected and didn't mean to mislead
anyone.
It has been a while since I looked at the ignitor and didn't have my
manual handy, but that's a bad defense <blushing>
This is why we need those pros, huh :)
Remco
Remco
I'm with Elle on the ignitor's failure mode. One would imagine that
these things just fail very quickly (unless it is thermal in nature,
oif course)
Could it be that the power to the ignitor is intermittent - A bad
contact in that path somewhere?
Imagine a bad intermittent contact on the 12V (or ground) to the
ignitor while the car is running. It would certainly translate into bad
spark (too narrow) and getting noise on the tach lead..
Remco
Elle
"Remco" <why...@yahoo.com> wrote
> I stand corrected and didn't mean to mislead
> anyone.
> It has been a while since I looked at the ignitor and
didn't have my
> manual handy, but that's a bad defense <blushing>
I've looked at the schematic I cited and Tegger's igniter
site closely at least half a dozen times each this past
year, and I forgot about the tach output until Michael P.
mentioned and I re-checked. That the Tach signal comes from
the igniter doesn't exactly pass the common sense test. At
least not at first blush, afaic.
I trust you see Tegger's site confirms the rest of your
conjecture, about the igniter being mostly a Darlington pair
transistor, yada.
> This is why we need those pros, huh :)
Yes, plus repair manual hounds. :-)
Remco
Elle wrote:
> "Remco" <why...@yahoo.com> wrote
> > I stand corrected and didn't mean to mislead
> > anyone.
> > It has been a while since I looked at the ignitor and
> didn't have my
> > manual handy, but that's a bad defense <blushing>
>
> I've looked at the schematic I cited and Tegger's igniter
> site closely at least half a dozen times each this past
> year, and I forgot about the tach output until Michael P.
> mentioned and I re-checked. That the Tach signal comes from
> the igniter doesn't exactly pass the common sense test. At
> least not at first blush, afaic.
>
Aw, shuks - now you're just trying to make me feel better :)
Yeah, that is kinda weird how they have the tach input coming from the
ignitor. One would imagine they could have just as easily taken the
signal going to the ignitor (possibly current boost it a little) and
feed it into the tach directly. Less wire and things that can go wrong,
imo...
Maybe they did that as a trouble shooting measure or we can use at as
such: This morning I cranked my wife's integra and noticed that while
cranking the tach moves very slightly. Maybe if a honda cranks and the
tach does not move it is an indication that the ignitor is bad..? That
would be an interesting thought.
Wonder how Michael is making out with this thing.
Remco
Elle
> Elle wrote:
> > "Remco" <why...@yahoo.com> wrote
> > > I stand corrected and didn't mean to mislead
> > > anyone.
> > > It has been a while since I looked at the ignitor and
> > didn't have my
> > > manual handy, but that's a bad defense <blushing>
> >
> > I've looked at the schematic I cited and Tegger's
igniter
> > site closely at least half a dozen times each this past
> > year, and I forgot about the tach output until Michael
P.
> > mentioned and I re-checked. That the Tach signal comes
from
> > the igniter doesn't exactly pass the common sense test.
At
> > least not at first blush, afaic.
> >
>
> Aw, shuks - now you're just trying to make me feel better
:)
You and anyone else who posts or lurks here. This was not an
easy catch, IMO. But as importantly, a group like this will
thrive only with open-mindedness and polite honesty. (Not
that I excel at these, but I know I'm supposed to try... :-)
> Yeah, that is kinda weird how they have the tach input
coming from the
> ignitor. One would imagine they could have just as easily
taken the
> signal going to the ignitor (possibly current boost it a
little) and
> feed it into the tach directly.
I thought maybe this might be happening anyway. The igniter
gets input from the ECU, of course, after all.
On further thought, the RPM signal really had to be
someplace in the vicinity of the camshaft or crankshaft. And
someplace protected, like the distributor housing. I am
thinking many other cars have their tach input coming from
somewhere within the distributor as well.
> Less wire and things that can go wrong,
> imo...
>
> Maybe they did that as a trouble shooting measure or we
can use at as
> such: This morning I cranked my wife's integra and noticed
that while
> cranking the tach moves very slightly. Maybe if a honda
cranks and the
> tach does not move it is an indication that the ignitor is
bad..?
Tegger's site certainly puts emphasis on this notion. See
http://www.tegger.com/hondafaq/igniter-operation/badigniter.
html
I see on further examination that Tegger's drawing (at
another of his sites on the igniter) has the Tach signal
coming out of the igniter's control chip, for one thing.
> That
> would be an interesting thought.
>
> Wonder how Michael is making out with this thing.
<Whispering: Why's one of our regulars buying a non-OEM
coil?>
Remco
Elle wrote:
>
> <Whispering: Why's one of our regulars buying a non-OEM
> coil?>
Lol -- yeah, I was kinda wondering the same thing. That aforementioned
mentioned politeness thing had me keeping it to myself.
Sorry for getting on your case, Michael. :)
Michael Pardee
> Wonder how Michael is making out with this thing.
>
> Remco
>
Thanks for asking! Kinda in a holding pattern. My daughter got back with it
just now, so I can check out the ignition switch and the engine ground. No
failures since Friday, though. Whether that's good news or bad news is a
matter of perspective :-}
Mike
karl
TOPIC: Ignition cut-out
http://groups.google.com/group/alt.autos.honda/browse_thread/thread/e8a5fd8cba927459
==============================================================================
> From: "alt.autos.honda group" <nor...@googlegroups.com>
> Date: Sun, 25 Dec 2005 07:20:29 +0000
>
>
> == 1 of 3 ==
> Date: Sat, Dec 24 2005 10:25 pm
> From: "Michael Pardee"
>
> This evening (yes - Christmas eve) my daughter's '93
> Accord LX (225K miles) suffered a short bout of engine
> failure. She described it as surging a couple times
> when she tried to accelerate, then the engine died when
> she braked. I quizzed her about the tach and she was
> clear it was jumping rather than swinging with the
> engine. It didn't start right away, but would sputter
> occasionally and eventually lit off as though flooded
> (which it probably was by then).
>
> The Main Relay and ignitor are each about a year old
> (but both are NAPA aftermarket, since the car insists
> on breaking down on Sundays and holidays). The timing
> belt is 4 years, 60K miles old. My son and I replaced
> the radiator about 2 weeks ago, so I am wondering if we
> stirred up evil spirits in the process of that. He bled
> the system carefully, but a leak in the lower radiator
> hose attachment may have let air in. I haven't done a
> visual inspection yet, but will in the morning.
>
> What comes to mind? Ignition switch? Some particular
> underhood wiring? Distributor? Something I'm
> forgetting? She is committed to driving to San Diego in
> a week or so and I'd sure like to sort this out by then.
> == 2 of 3 ==
> Date: Sun, Dec 25 2005 5:31 am
> From: "Elle"
>
> How old's the ignition coil?
>
> I'd try to do a check of it early on. Dying when
> braking--then being able to restart it after a cooldown
> period, at least until the coil fails completely--is a
> symptom.
>
> I know you have a lot of experience with Hondas. This is
> just where I'd start, based on the car's age and
> symptoms.
> == 1 of 1 ==
> Date: Sun, Dec 25 2005 11:14 am
> From: "Remco"
>
>
> I wonder if the problem is electrical in nature, because
> the RPMs were jumping around wildly.
>
> Since the tach and engine timing both get their signal
> from the crank sensor, I'd also look in that area.
> == 2 of 5 ==
> Date: Sun, Dec 25 2005 4:39 pm
> From: "Remco"
>
snip
>
> Not sure about any previous post on this issue, but the
> ignitor seems to just be a larger power transistor
> (probably a darlington, but that's besides a point).
>
> The way this transistor is configured, it simply acts as
> a switch that that closes/opens a contact when its input
> changes states (to simplify it all, imagine a relay with
> a coil and contact - that is not quite what a transistor
> is, but behaves quite similarly the way an ignitor is
> hooked up).
> When a level is applied to its input, it switches the
> primary side (the 12V side, basically) of the coil to
> ground and does this at a very high rate of speed. The
> secondary of the coil is what generates a high voltage
> spark.
> The output of the ignitor does not seem to attach to
> anything else so iti it breaks you won't have spark.
>
> I don't think the tach is getting its signal from the
> ignitor, so don't see how one can tell by the tach that
> the ignitor is bad. If you somehow can detect this on
> the tach, it must be some sort of weird artifact.
I thought coils last forever. I never had to replace a
coil, rotor, cup, or wire on any of my cars. I have an
Accord that soon will be 22. But on this list it is
very frequently recommended to replace, even on young
cars, all kind of ignition parts. To me this sounds
like "it won't do any harm, so lets replace it."
I have a question about the original message:
> ... suffered a short bout of engine
> failure. She described it as surging a couple times
> when she tried to accelerate, then the engine died
> when she braked. I quizzed her about the tach and
> she was clear it was jumping rather than swinging
> with the engine.
Surging - meaning the rpm increased (suddenly,
audibly?) more than expected, right? With the cars I am
familiar this would not happen when any of the ignition
parts fail, to the contrary, they would slow down.
In order for the engine to rev up, without any
corresponding increase of the speed, there must be a
disconnect between engine and road, for example
slipping of the clutch or AT - which most likely
happens when they cannot transmit the increased power
during acceleration.
.
Jim Yanik
news:1135623154....@g47g2000cwa.googlegroups.com:
I doubt a starter will crank the motor fast enough to make any significant
reading on the tach.
What's the smallest RPM indication on the tach,100 RPM?
No starter turns the motor that fast.
--
Jim Yanik
jyanik
at
kua.net
Jim Yanik
news:1135630208.9...@g43g2000cwa.googlegroups.com:
I wonder if using a non-integral distributor cap/coil like the separate MSD
racing coil and plain distributor cap would be a more durable system?
MSD is supposed to have a good reputation.
I never liked the idea of an integral cap and coil.
Remco
it starts. It would be interesting to see if it still does that with a
bad ignitor..
Remco
Elle
> "Remco" <why...@yahoo.com> wrote
Doesn't this assume that it's mechanical motion of the
crankshaft or camshaft that actuates the tachometer? If so,
I'm not so sure I buy your reasoning.
I thought it was strictly a digital signal from the igniter
(in particular, its computer chip) that actuated the
tachometer. That is, the igniter computer chip certainly is
not actually sensing degrees of crank- or camshaft rotation.
Instead it receives signals from the ECU to excite the base
of the igniter's transistor yada, in proportion to the rate
at which the primary of the coil is supposed to be
energized. This of course determines the plug firing rate,
which will certainly determine, ordinarily, the engine RPM.
The computer chip "measures" engine RPM through on/off
switching of some kind (and so is digital and not analog in
nature?). I would think that the momentary signals from the
ECU at starting may very well cause something like noise in
the tachometer signal, causing it to jump a bit.
Again, Tegger's site puts a lot of emphasis on watching the
tach to diagnose a bad igniter.
Remco
Makes sense to me. If the ignitor's drive comes from the ECM and
clearly fires when the car is starting (one needs spark, after all),
you should see it on the tach, albeit at a very low frequency.
I had not read tegger's page on the ignitor in quite a while until
today. Seems like you can indeed tell by looking at the tach wheter the
ignitor is bad.
(That site is quite a great resource, isn't it? He's done a hell of a
job on it - can't get over that every time I visit it..)
Remco
Jim Yanik
news:1135648187.6...@g49g2000cwa.googlegroups.com:
Remember that the internal circuit of the "igniter" has an IC to measure
coil current("dwell")and provide the proper drive to the Darlinton current
switch. The tach drive could come from the IC. I haven't yet found the
exact IC number to provide a datasheet to examine,to know for certain.
Jim Yanik
news:iP1sf.861$M%4....@newsread3.news.atl.earthlink.net:
But during CRANKING,the ECU reads the crankshaft (CK)sensor to determine
firing pulses to FEED the igniter.So,tach pulses are still dependent on the
ECU and engine RPM.
>
> I thought it was strictly a digital signal from the igniter
> (in particular, its computer chip) that actuated the
> tachometer. That is, the igniter computer chip certainly is
> not actually sensing degrees of crank- or camshaft rotation.
No,the crankshaft sensor is doing that.
Spark plugs fire -at a certain position of the piston in each cylinder-
,determined by the ECU,thru the CK sensor.Not by RPM.
> Instead it receives signals from the ECU to excite the base
> of the igniter's transistor yada, in proportion to the rate
> at which the primary of the coil is supposed to be
> energized. This of course determines the plug firing rate,
> which will certainly determine, ordinarily, the engine RPM.
You have it backwards.On *starting*(cranking),the CK sensor reads engine
crank position,and the ECU reads that and calculates the triggers for the
igniter.The starter determines the cranking RPM,the ECU reads it thru the
CKsensor (piston position)and triggers the igniter,where a supplementary
signal is tapped to run the tach.
BTW,the igniter fires the coil *4 times* for each revolution of the
crank,so the tach circuit divides by 4 to get true RPM,or the igniter IC
does that internally.Probably the latter.
> The computer chip "measures" engine RPM through on/off
> switching of some kind (and so is digital and not analog in
> nature?). I would think that the momentary signals from the
> ECU at starting may very well cause something like noise in
> the tachometer signal, causing it to jump a bit.
>
> Again, Tegger's site puts a lot of emphasis on watching the
> tach to diagnose a bad igniter.
>
>
>
The IC inside the igniter is to optimize coil current for hottest spark,and
provide proper base drive for the Darlinton.The coil generates it's HV on
the *shut-off* of the Darlington (that's the "flyback" pulse),not the turn-
on,which is only to *charge* the coil's magnetic field.The IC is there to
insure the coil gets a full charge no matter what RPM,that used to be
called "dwell time",the time the points were closed and charging the
coil,flyback and HV occuring when the points *opened* after charging the
coil.
Elle
> "Elle" <honda....@earthlink.net> wrote
I just omitted the effect of the CK sensor. The main
point--that the signal to the tach is digital and in
response to the ECU signal, and may be sufficiently
electronically yada noisy to yield some jiggling of the tach
upon starting--stands.
> On *starting*(cranking),the CK sensor reads engine
> crank position,and the ECU reads that and calculates the
triggers for the
> igniter.The starter determines the cranking RPM,the ECU
reads it thru the
> CKsensor (piston position)and triggers the igniter,where a
supplementary
> signal is tapped to run the tach.
Yeahbut while starting, well within one camshaft revolution
the ECU is signalling the igniter, whose computer chip is
still signalling the tach.
I'm just saying ISTM there's some kind of signal to the tach
being generated, starting well within one camshaft
revolution.
> BTW,the igniter fires the coil *4 times* for each
revolution of the
> crank,
I believe you mean for each /two revolutions/ of the crank.
It's a four-stroke engine; takes two revolutions for each
piston to have gone through firing TDC (in a four-cylinder
car) once; etc.
Elle
On Tegger's site:
> (That site is quite a great resource, isn't it? He's done
a hell of a
> job on it - can't get over that every time I visit it..)
Today I was reading his fairly new "online OEM parts
sources" site. Quite an interesting read. I hope to try the
Colorado online parts store he lists sometime soon. Its
shipping appears a little more straightforward and may be
cheaper than Majestic's or SLHonda's. The parts prices
themselves look about the same.
Doug McCrary
> > BTW,the igniter fires the coil *4 times* for each
> revolution of the
> > crank,
>
> I believe you mean for each /two revolutions/ of the crank.
> It's a four-stroke engine; takes two revolutions for each
> piston to have gone through firing TDC (in a four-cylinder
> car) once; etc.
>
>
FWIW, there's no real reason to "NOT" have it fire. There's just nothing there
to burn half the time.
Elle
> Elle <honda....@earthlink.net> wrote
> > > BTW,the igniter fires the coil *4 times* for each
> > revolution of the
> > > crank,
> >
> > I believe you mean for each /two revolutions/ of the
crank.
> > It's a four-stroke engine; takes two revolutions for
each
> > piston to have gone through firing TDC (in a
four-cylinder
> > car) once; etc.
> >
> >
> FWIW, there's no real reason to "NOT" have it fire.
Sure there is. For one thing, it would shorten the life of
spark plugs, wires, and coil, potentially by quite a lot.
Weird comment...
Michael Pardee
news:1135638874.9...@g44g2000cwa.googlegroups.com...
> I thought coils last forever. I never had to replace a
> coil, rotor, cup, or wire on any of my cars. I have an
> Accord that soon will be 22. But on this list it is
> very frequently recommended to replace, even on young
> cars, all kind of ignition parts. To me this sounds
> like "it won't do any harm, so lets replace it."
>
The only definite coil failures I've had have been a Nissan that gave one
"pop" when starting, then nothing, and my son's Acura coil that objected to
not having a place for the spark to go. Old time coils practically never
failed; like the old Mopar slant 6s, they didn't have the power to blow
themselves up. Modern coils run at much higher power and are no longer oil
filled, so failures are not unusual. My experience with electrical parts of
all sorts shows the pattern that power handling devices gradually cook
themselves one way or another. 200K+ miles on a coil certainly puts it in
the range of "untrustworthy," and when a contributor I respect says she has
seen intermittent failures in them before they die I think that's reason to
change it out on suspicion... while still investigating other possibilities.
> I have a question about the original message:
>
>> ... suffered a short bout of engine
>> failure. She described it as surging a couple times
>> when she tried to accelerate, then the engine died
>> when she braked. I quizzed her about the tach and
>> she was clear it was jumping rather than swinging
>> with the engine.
>
> Surging - meaning the rpm increased (suddenly,
> audibly?) more than expected, right? With the cars I am
> familiar this would not happen when any of the ignition
> parts fail, to the contrary, they would slow down.
>
I don't think I described it well. The surging was intermittent loss of
power, and of course she instinctively pressed on the gas to compensate. We
all know it rarely helps, but we all do it :-)
A follow-up... the symptoms haven't returned yet. This model has a solid
ground to the chassis near the battery, and the battery negative cable also
takes the ground to the engine, so my concern that we left the ground loose
was unfounded. The ignition switch seems solid, but I'd like to check it
when it is cold, too.
Mike
karl
TOPIC: Ignition cut-out
http://groups.google.com/group/alt.autos.honda/browse_thread/thread/e8a5fd8cba927459
============================================================
> == 4 of 11 ==
> Date: Tues, Dec 27 2005 2:39 am
> From: "Elle"
snip
> Instead [the igniter computer chip] receives signals
> from the ECU to excite the base of the igniter's
> transistor yada, in proportion to the rate at which
> the primary of the coil is supposed to be energized.
> This of course determines the plug firing rate, which
> will certainly determine, ordinarily, the engine RPM.
Most interesting.
.
Elle
> Old time coils practically never
> failed; like the old Mopar slant 6s, they didn't have the
power to blow
> themselves up. Modern coils run at much higher power and
are no longer oil
> filled, so failures are not unusual. My experience with
electrical parts of
> all sorts shows the pattern that power handling devices
gradually cook
> themselves one way or another. 200K+ miles on a coil
certainly puts it in
> the range of "untrustworthy," and when a contributor I
respect says she has
> seen intermittent failures in them before they die I think
that's reason to
> change it out on suspicion... while still investigating
other possibilities.
Toss in that Tegger put this item's troubleshooting and
replacement, with quite a lot of detail, into his FAQ.
Meaning the coil's failure is reported quite a bit here.
My 91 Civic's first coil lasted ten years, 120k miles. My
one non-OEM coil lasted less than two years, about 35k
miles. Firestone charged me an arm and a leg for that
non-OEM coil, too.
'Course, let me be the first to point out that non-OEM
ignition wires may have played a role. Tegger's 1991
Integra, at over 240k miles IIRC, is still on its original
coil. He appears to take fastidious care of his ignition
electrical parts (rotor, cap, wires, plugs all replaced at
five years by him, all OEM IIRC). A lesson for us all, IMO.
I read the other day an article by Auto tech writer Larry
Carley. He also reported that not taking good care of
ignition wires will shorten coil lives.
This might not solve your daughter's car's problem. Again,
it's just where I would start. Though I would have taken
resistance measurements, per the manual's specs, on the old
coil before replacing it, too. Not that you have time over a
possible holiday to deal with this.
Elle
> My 91 Civic's first coil lasted ten years, 120k miles. My
> one non-OEM coil lasted less than two years, about 35k
> miles.
Correction. The non-OEM coil lasted a little less than 20k
miles. About half that time it was also feeding non-OEM
wires.
Jim Yanik
news:EZ3sf.898$M%4....@newsread3.news.atl.earthlink.net:
Meaning there's ON and OFF and no inbetween.
> and in
> response to the ECU signal, and may be sufficiently
> electronically yada noisy to yield some jiggling of the tach
> upon starting--stands.
The jitter would be due to normal timing variation of firing pulses from
the ECU/CKsensor system,not from "noise" which would not affect a digital
signal.(after all,it's a closed-LOOP system.)
And the inertia of the digital to analog conversion to drive the tach
needle smooths out jitter.
The tach jitter is essentially meaningless,as the motor is not turning fast
enough to give a true indication of RPM,RPMs being below the minimum
calibrations of the tach dial.
Note I previously said "significant reading".
>> >> I doubt a starter will crank the motor fast enough to
> make
>> > any significant
>> >> reading on the tach.
>> >> What's the smallest RPM indication on the tach,100 RPM?
>> >> No starter turns the motor that fast.
Actually,I think the RPM calibration begins at a few hundred RPM,then
linearly increases from there.
>
>> On *starting*(cranking),the CK sensor reads engine
>> crank position,and the ECU reads that and calculates the
> triggers for the
>> igniter.The starter determines the cranking RPM,the ECU
> reads it thru the
>> CKsensor (piston position)and triggers the igniter,where a
> supplementary
>> signal is tapped to run the tach.
>
> Yeahbut while starting, well within one camshaft revolution
> the ECU is signalling the igniter, whose computer chip is
> still signalling the tach.
(well,the igniter chip is not a "computer" chip,it's analog;a current-
sensing comparator to insure a full coil charge,that "dwell" stuff.)
>
> I'm just saying ISTM there's some kind of signal to the tach
> being generated, starting well within one camshaft
> revolution.
Yes,the tach pulses get generated,but not enough pulses or fast enough to
be significant.I haven't gotten a look at the specific circuitry of the
igniter IC to be sure that tach pulses would not be generated even if the
Darlington was blown and no current being switched thru the coil.The ECU
could be triggering the IC and tach pulses passed on,but no Darlington
drive or a dead Darlington.
>
>> BTW,the igniter fires the coil *4 times* for each
> revolution of the
>> crank,
>
> I believe you mean for each /two revolutions/ of the crank.
> It's a four-stroke engine; takes two revolutions for each
> piston to have gone through firing TDC (in a four-cylinder
> car) once; etc.
>
>
You got me there.
Elle
> > point--that the signal to the tach is digital
>
> Meaning there's ON and OFF and no inbetween.
>
> > and in
> > response to the ECU signal, and may be sufficiently
> > electronically yada noisy to yield some jiggling of the
tach
> > upon starting--stands.
>
> The jitter would be due to normal timing variation of
firing pulses from
> the ECU/CKsensor system,
Sure. I was being loose with "noise" and probably crossed
the line to inaccuracy.
> not from "noise" which would not affect a digital
> signal.(after all,it's a closed-LOOP system.)
AFAIC, noise can be a problem, regardless of whether the
system is closed loop or open loop.
For example, the ignition system has a radio noise condenser
in it (meaning, I hope as you know, this condenser reduces
interference with the ECU, the car radio, and probably the
igniter's transistors. Reports from two of our regulars here
are that this condenser's removal or aging can definitely
adversely affect ignition and so engine performance.
> And the inertia of the digital to analog conversion to
drive the tach
> needle smooths out jitter.
> The tach jitter is essentially meaningless,as the motor is
not turning fast
> enough to give a true indication of RPM,RPMs being below
the minimum
> calibrations of the tach dial.
Meaningless as far as indicating actual RPM. Meaningful as
far as possibly using it to diagnose an igniter failure. Or
so it seems to me for now.
I don't agree or disagree with the rest. My only interest
was proposing that the Tach response could give an
indication of igniter mis-operation. No disrespect intended;
I prefer to get the bulk of my electronics lessons from
other than Usenet. It's too hard to communicate important
detail on internet boards.