Ignition cut-out

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.

"Michael Pardee" wrote

Accord LX (225K miles)

as surging a

died when she

was jumping rather

but would sputter

(which it probably was

both are NAPA

Sundays and

son and I replaced

stirred up evil

carefully, but a leak in

haven't done a

underhood wiring?

driving to San

by then.

I'd forgotten about that! The coil is the original. I might be wise to 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

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

I thought I read on here recently that an erratic tach that precedes a cut-out is a sign of a bad igniter.

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

Actually, I believe the tach does get its signal from a separate lead on the 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

"Michael Pardee" wrote

separate lead on the

The electrical diagram for the ignition system suggests you are remembering correctly. See the top schematic at

. Tegger'sversion appears to confirm it:

the igniter

from March, IIRC. I

that there is no

ECU... i.e. igniter

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.

I have a Bosch coil ordered through alleurasianautoparts.com, should be here 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

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

This is why we need those pros, huh :)

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

"Remco" wrote

didn't have my

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.

Yes, plus repair manual hounds. :-)

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

igniter

P.

from

At

:)

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... :-)

coming from the

taken the

little) and

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.

can use at as

that while

cranks and the

bad..?

Tegger's site certainly puts emphasis on this notion. See

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.

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

============================================================================== TOPIC: Ignition cut-out

snip

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:

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.

.

"Remco" wrote in news: snipped-for-privacy@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.

"Remco" wrote in news: snipped-for-privacy@g43g2000cwa.googlegroups.com:

Well, FWIW on my wife's Integra I see the needle bump around zero when it starts. It would be interesting to see if it still does that with a bad ignitor..

Remco