Honda Car Forum

Tegger's FAQs has references to dwell meters - e.g for testing the coil. I
have never heard of a dwell meter before and they aren't widely available
from what I can tell..

Wondering if my digital electric multimeter can do this diagnostic...?
Starting Problems
.... is this: Connect a dwell meter to the negative coil terminal and to
ground.
Crank the engine: No dwell, bad igniter; Dwell but no spark, bad coil. ...
www.tegger.com/hondafaq/startproblems.html

hutchtoo wrote:
> Tegger's FAQs has references to dwell meters - e.g for testing the coil. I
> have never heard of a dwell meter before and they aren't widely available
> from what I can tell..
>
> Wondering if my digital electric multimeter can do this diagnostic...?
> Starting Problems
> ... is this: Connect a dwell meter to the negative coil terminal and to
> ground.
> Crank the engine: No dwell, bad igniter; Dwell but no spark, bad coil. ...
> www.tegger.com/hondafaq/startproblems.html

unless it's the automotive variety, probably not. but don't worry about
it. if your car has electronic ignition, it's irrelevant because
"dwell" is all determined by the ecu or ignition module. all that
matters is that the igniter switches, that the coil fires, and that the
plugs spark.

use of the word "dwell" is a throwback to the old days of contact
breakers where the contacts had to "dwell" for long enough to energize
the coil. too little dwell, not enough spark energy, especially at high
rpm's. too much, coil ran too hot.

On Sat, 3 Sep 2005 13:44:05 -0400, "hutchtoo" <hutchtoo@gmail.com>
wrote:

>Tegger's FAQs has references to dwell meters - e.g for testing the coil. I
>have never heard of a dwell meter before and they aren't widely available
>from what I can tell..
>

In the old mechanical breaker points ignition systems, dwell angle is
the angle of rotation of the distributor through which the mechanical
points are "closed. The points must remain closed for a sufficient
time to store energy in the coil sufficient to produce a good, hot
spark at the plug when the points open. In a four cylinder engine,
dwell angle is typically around 60 degrees.

There is an equivalent measurement in an electronoic ignition system
that is usually called dwell, but it is not properly dwell in the old
contact points sense. This quantity is electronically controlled. I am
not sure what an old fashioned dwell meter would be measuring in a
modern electronic ignition engine. However, I do not think it would be
useful information. There is typically no way to make adjustments on
most electronic ignition systems anyway.

Hope this helps.

Elliot Richmond
Freelance Science Writer and Editor

In article <vq1kh1tdg5v0ipph2ht4ftsljqnbflr1gk@4ax.com>,
xmrichmond@xaustin.xrr.xcom says...
> On Sat, 3 Sep 2005 13:44:05 -0400, "hutchtoo" <hutchtoo@gmail.com>
> wrote:
>
> >Tegger's FAQs has references to dwell meters - e.g for testing the coil. I
> >have never heard of a dwell meter before and they aren't widely available
> >from what I can tell..
> >
>
> In the old mechanical breaker points ignition systems, dwell angle is
> the angle of rotation of the distributor through which the mechanical
> points are "closed. The points must remain closed for a sufficient
> time to store energy in the coil sufficient to produce a good, hot
> spark at the plug when the points open. In a four cylinder engine,
> dwell angle is typically around 60 degrees.
>
> There is an equivalent measurement in an electronoic ignition system
> that is usually called dwell, but it is not properly dwell in the old
> contact points sense. This quantity is electronically controlled. I am
> not sure what an old fashioned dwell meter would be measuring in a
> modern electronic ignition engine. However, I do not think it would be
> useful information. There is typically no way to make adjustments on
> most electronic ignition systems anyway.
>
> Hope this helps.
>
> Elliot Richmond
> Freelance Science Writer and Editor
>
The 'Old' Dwell meters were usually based on continuity testers. I
suppose you could measure continuity with it. I have seen articles in
the electronic trade magazines about using Volt-Ohm (V.O.M.)meters for
measuring point dwell. This was back in the late sixties and early
seventies. I know I'm showing my age here.

Randy

On Sat, 3 Sep 2005 17:01:35 -0700, Randy Hunt <rhunt960@tco.net>
wrote:

>The 'Old' Dwell meters were usually based on continuity testers. I
>suppose you could measure continuity with it. I have seen articles in
>the electronic trade magazines about using Volt-Ohm (V.O.M.)meters for
>measuring point dwell. This was back in the late sixties and early
>seventies. I know I'm showing my age here.

Young whippersnapper!

My dwell meter scale read in degrees. I never took it apart but my
guess was that it was some sort of RC circuit (or maybe IRC) with a
voltmeter reading the potential across the capacitor. The longer the
dwell, the more charge the capacitor would accumulate, and the higher
the voltage, which would then read as a larger dwell angle.


Elliot Richmond
Freelance Science Writer and Editor

Elliot Richmond wrote:
> On Sat, 3 Sep 2005 17:01:35 -0700, Randy Hunt <rhunt960@tco.net>
> wrote:
>
>
>>The 'Old' Dwell meters were usually based on continuity testers. I
>>suppose you could measure continuity with it. I have seen articles in
>>the electronic trade magazines about using Volt-Ohm (V.O.M.)meters for
>>measuring point dwell. This was back in the late sixties and early
>>seventies. I know I'm showing my age here.
>
>
> Young whippersnapper!
>
> My dwell meter scale read in degrees. I never took it apart but my
> guess was that it was some sort of RC circuit (or maybe IRC) with a
> voltmeter reading the potential across the capacitor. The longer the
> dwell, the more charge the capacitor would accumulate, and the higher
> the voltage, which would then read as a larger dwell angle.

That's how I would build one - dead simple


---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 0535-3, 09/02/2005
Tested on: 9/3/2005 7:52:57 PM
avast! - copyright (c) 1988-2005 ALWIL Software.
http://www.avast.com

In article <usekh114fbrkbecrjq0fm3v766hoim5gfc@4ax.com>,
xmrichmond@xaustin.xrr.xcom says...
> On Sat, 3 Sep 2005 17:01:35 -0700, Randy Hunt <rhunt960@tco.net>
> wrote:
>
> >The 'Old' Dwell meters were usually based on continuity testers. I
> >suppose you could measure continuity with it. I have seen articles in
> >the electronic trade magazines about using Volt-Ohm (V.O.M.)meters for
> >measuring point dwell. This was back in the late sixties and early
> >seventies. I know I'm showing my age here.
>
> Young whippersnapper!
>
> My dwell meter scale read in degrees. I never took it apart but my
> guess was that it was some sort of RC circuit (or maybe IRC) with a
> voltmeter reading the potential across the capacitor. The longer the
> dwell, the more charge the capacitor would accumulate, and the higher
> the voltage, which would then read as a larger dwell angle.
>
>
> Elliot Richmond
> Freelance Science Writer and Editor
>
Some of them would simply let the longer the dwell be indicated by the
lower resistance read. Letting the mechanical inertia of the meter
integrating the pulses into a smooth reading.

Randy

Randy Hunt wrote:

> In article <usekh114fbrkbecrjq0fm3v766hoim5gfc@4ax.com>,
> xmrichmond@xaustin.xrr.xcom says...
>
>>On Sat, 3 Sep 2005 17:01:35 -0700, Randy Hunt <rhunt960@tco.net>
>>wrote:
>>
>>
>>>The 'Old' Dwell meters were usually based on continuity testers. I
>>>suppose you could measure continuity with it. I have seen articles in
>>>the electronic trade magazines about using Volt-Ohm (V.O.M.)meters for
>>>measuring point dwell. This was back in the late sixties and early
>>>seventies. I know I'm showing my age here.
>>
>>Young whippersnapper!
>>
>>My dwell meter scale read in degrees. I never took it apart but my
>>guess was that it was some sort of RC circuit (or maybe IRC) with a
>>voltmeter reading the potential across the capacitor. The longer the
>>dwell, the more charge the capacitor would accumulate, and the higher
>>the voltage, which would then read as a larger dwell angle.
>>
>>
>>Elliot Richmond
>>Freelance Science Writer and Editor
>>
>
> Some of them would simply let the longer the dwell be indicated by the
> lower resistance read.

There should be no change in resistance - either it's infinite (points
open) or near-zero (points closed).

> Letting the mechanical inertia of the meter integrating the pulses
> into a smooth reading.

That's how almost all tachometers work.

>
> Randy


---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 0535-3, 09/02/2005
Tested on: 9/4/2005 4:44:13 PM
avast! - copyright (c) 1988-2005 ALWIL Software.
http://www.avast.com

"hutchtoo" <hutchtoo@gmail.com> wrote in message news:wvSdnV8xsYt9fYTeRVn-sQ@rcn.net...
> Tegger's FAQs has references to dwell meters - e.g for testing the coil. I
> have never heard of a dwell meter before and they aren't widely available
> from what I can tell..

Replace the dwell with a spare bulb from the taillights.

> Wondering if my digital electric multimeter can do this diagnostic...?

Yes/No. If the coil is severely dead there is no load. And no
load = no signal. That's why the bulb works.

"Elliot Richmond" <xmrichmond@xaustin.xrr.xcom> wrote
> I am
> not sure what an old fashioned dwell meter would be measuring in a
> modern electronic ignition engine. However, I do not think it would be
> useful information.

A dwell meter can measure fuel injector's richness, although
the correct way is to measure current.