Will cheap multimeter work with a DVA peak voltage adapter?

[hkeiner]

I want to test the ignition on my 1996 Mercury 150hp V6 outboard using a DVA meter (or similar). Basically, I want to test that the spark is strong enough at idle. My motor runs fine at WOT but does not idle well. I want to eliminate a weak spark as a possible culprit before I remove/clean/adjust/mess with my carbs or timing. I already checked the spark with an inline spark tester and saw that I have a spark on all 6 cylinders.

The literature that I have read about DVA adapters says that the adapter should be used with a "good" multimeter. (emphasis added). I am not clear, however, on what would be considered a good enough multimeter or what would be the problem with using a cheaper (not so good) multimeter.

Questions:

1) I already have a $20 analog multimeter that I bought at Home Depot. Would this multimeter be OK to use with the DVA adapter or is it highly beneficial to have a better one, like a Fluke 16?

2) Is a Piercing Probe Set (sticks a small needle into the spark plug wire) needed to test the spark or is there another way to do this without spending money for a probe set?


Thanks for any information on this

DVA Adapter:

Probe set:

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

if the DVA adapter will plug into your meter and your meter is digital it willmost likly work fine, my meter or one of them was 35 dollars at radio shack.
the DVA wont check spark plug firing voltage as it does not go into the Kv range.
it will test ign coil primary voltage which should stay in the 150V range.
I dont use piercing probes cause I have enough issues with salt corrosion without breaking the insulation.
remember the switch box does not increase voltage, it rectifies and stores the AC voltage from the stator and stores it until a trigger is applied then it discharges the capacitor through the ign coil primary windings. the ign coilis in charge of stepping the voltage up to the 5-10 Kv range.

 

[Texasmark]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Rodbolt.

Your second paragraph is excellent. Very nice job of saying what needed to be said in nice layman's terms.....and it was accurate. 8)

Mark

 

[hkeiner]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

The DVA wont check spark plug firing voltage as it does not go into the Kv range. It will test ign coil primary voltage which should stay in the 150V range.

I am a bit (very) confused about if/how to test the spark quality at idle using a DVA meter (or DVA adapter). You seemed to indicate that the spark voltage in the spark plug wire can not be tested with a DVA meter. I thought that the purpose of the Piercing Probe Set was to do that exact thing. In reading the description of the Piercing Probe Set for sale on a Marine website(see text below) it seems to also indicate that this can be done.

Alternatively, will testing the ignition coil primary voltage at the coil sufficently test the qualitiy of the spark, making a test of voltage within the spark plug wire unneccessary anyways?

Thanks for any clarification.


Description of Piercing Probe Set for sale on www.ebasicpower.com :

No need to disconnect harness or wires. Fully insulated probes have a spring loaded clamp with tiny stainless steel pin that self centers and punctures the insulation. (Hole will normally reseal itself when wire heats up). Ideal for taking DVA readings on all engines and Jet Drive systems. This set is highly recommended for use with all meters and peak reading adapters

 

[seahorse5]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Like Rodbolt said, in salt water areas do not pierce the wires. It is best to use the adapters or clips recommended by the outboard manufacturer.

Also be advised that some digital meters are not shielded enough and kind of read crazy when too close to the RFI of a CD ignition system. In the past, some Radio Shack meters had a problem with that.

 

[hkeiner]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Like Rodbolt said, in salt water areas do not pierce the wires. It is best to use the adapters or clips recommended by the outboard manufacturer.

Also be advised that some digital meters are not shielded enough and kind of read crazy when too close to the RFI of a CD ignition system. In the past, some Radio Shack meters had a problem with that.

Commander,

Thanks for the reply. Does your response mean that voltage can be tested in the spark plug wire as long as a suitable meter setup is used (i.e., suitable DVA meter or a suitable multimeter with DVA adapter)?

I am using my boat solely on freshwater in Arizona (i.e., no saltwater). If using a piercing probe set isn't the best choice for connecting the DVA to the spark plug wires, what other "adapters or clips" could be used instead? I read my Mercury shop manual and have searched the internet and I found no indication of any other types of adapters or clips for this purpose.

Thanks

 

[Laddies]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

You can't read coil output with a DVA, that takes a osilloscope or a meter capable of testing KV. A DVA simple captures AC peak voltage so you can check for low voltage between the stator output and the coil input so if It's AC current then it's not really a coil is it, it'd a transformer

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

actually the peak from the stator is AC. its rectified by a full wave recitifier to DC and stored in a capacitor in the switchbox.
the DC output of the switch box when the SCR is triggered by the AC voltage from the trigger coil is discharged through the ignition coil primary windings to ground.
yes the ign coil is a transformer.
a step up transformer to be more technical.
the input to the coil primary is a rapid DC pulse that acts almost like AC. it goes from 0V to 150V and back very rapidly.
in the millisecond range.

the input to most modern ADI systems is in the 150-300VAC peak voltage range.
most switchboxs,powerpacks or CDI units,whatever you wish to call them, have voltage regulators to prevent stator input overvoltage.
the regulated and rectified DC voltage feed to the ignition coil from the capacitor is further stepped up at the ign coil from the 150Vpeak range to the 5000-10,000 V range.
Kv=1000's of volts.
so in this application most likly you meter would just overload and display garbage if you tried to use it on actual fireing voltage.
the snapon Kv tester is about 229 dollars now.
I own 2.
the CD77 meter is about 260 and I own 2.
the rapair and other DVA adapters are usually between 40 and 70 dollars. I own 2.
the nice fluke is over 250 now I own none.
an equivalent meter from radio shack is less than 50 but is not as shock resitant if dropped.
neither brand swims at all.

 

[seahorse5]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

neither brand swims at all.

Dont we know it !!!!!!

 

[hkeiner]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Thanks for all of the information. I've learned a lot about what I can and can't readily do in regards to testing the quality of the spark at idle.

Since I can not readily test the voltage in the spark plug wire with a meter, my conclusion as to how I can best confirm that the quality of the spark at idle is strong enough (so as to not cause idle problems) is to do the following:

1) Use a DVA meter to test the voltage going into the coils from the switchboxes. If the voltage is up to snuff, I can assume that the ignition components (except for the coil, spark plug wire, or spark plug) are working OK in regards to the strength of the spark at idle, .

2) Use an adjustable spark tester to observe the color and brightness of the spark while cranking the motor with all other plugs wires grounded. If the spark looks blue and bright, I can assume that the coil and spark plug wire are working OK in regards to the strength of the spark at idle.

3) Replace the old spark plugs with new ones and observe any change in idle performance. If no change in idle performance, I can assume that the old spark plugs are OK.

Is my approach pretty much on target to identify or eliminate a weak spark as the cause of poor idle performance? I have already observed that all of the plugs have a spark and that none of them skip a spark when the motor is cranked with the starter and also that the motor runs fine at WOT. If I eliminate a weak spark as a culprit, then I'll look towards the carb, timing, and other possible causes.

Thanks again for your help.

 

[Laddies]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

You got it now hkeiner, good luck
Hey rodbolt, thought I was the only one in the world that knew they were step up transformers, not as smart as I thought I was, but we keep learning ever day don't we--Bob 8)

 

[72SideWinderSS]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Or if you still want a kv tester have a look at
http://www.stevensinstrument.com/spark_checkers.htm

 

[JUSTINTIME]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

Or if you still want a kv tester have a look at
http://www.stevensinstrument.com/spark_checkers.htm

i'm about to order that tool

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

for the pro tech the Kv tester is absolutly invaluable.
it can find issues you never dreamed of once you understand what is going on.
its a tad pricey for the home tech though.
but the peak input to the ign coil is a good indication of if correct voltage is avalible for proper secondary ign operation.

 

[JUSTINTIME]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

main reason i want it is that the Stevens tach meter i have does not work on Honda's. i really want it for the rpm feature mainly
plus i get 20% off dealers price since i am a student!

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

justintime
I cant access the item from iboats.
neither of my Kv testers reads RPM.
my timing light will.
are we discussing the same tool ?

 

[JUSTINTIME]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

i was referring to the TD-96 Analog Tachometer/Dwellmeter i have
on Honda's motors it can not pick up the signal

so i was thinking on the TA-100 SmarTach+ - digital tachometer/KV meter


try this http://www.stevensinstrument.com/

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

http://www.thetoolwarehouse.net/shop/SR-TA100.html
is this a similar tool?

 

[JUSTINTIME]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

same tool

but i was refering to this tool the stevens tach/dwell meter that will not pick up honda
that is why i want the KV/rpm tool

 

[rodbolt]

Re: Will cheap multimeter work with a DVA peak voltage adapter?

beats me, I have never personally tried either tool.
just be aware that some ign systems are very "dirty" and sometimes will give false readings.
you may write and ask if you can test one before buying.
but at 120 dollars it may be worth the risk.
my Kv tester is an invaluable part of my diagnostic equipment.
it allows for rapid isolation of affected cylinders be it ign or mechanical.