Another Dyna S Question.

The setup: Dyna 3 Ohm Coils 4-5 years old. Dyna S Ignition about 10 years old or more. Dyna Solid Copper Core Plug Wires about 2 years old. NGK B8ES Plugs. Yusa Battery about 3 years old. WiredGeorge Coil Mod. Battery holds charge and is on Tender.
Whats happening: Starts first push of the starter button warms up and idles at about 1000-1100rpm on the OEM Tach. Battery charging at about 13.5vdc at idle. With Motor off and Ign and kill sw on with WG coil Mod Batt voltage 12.5-12.75vdc at coils then slowly drops the longer Ign and kill sw is on. Voltage at Coils is around 11VDC with out Coil Mod. Ok got a new Cen-Tech Automotive Meter like Old Man Rocks (yeah I liked it) wanted to beable to check my RPM's a little closer. Followed Directions and checked with OMR because I can not get a solid rpm reading. Meter jumps around 200-1500 RPM. Checked Meter on My Mazda Truck and it is dead on and Solid reading. Decided to check the Coil voltage with the Motor running and its all over the place just like the rpm reading. Both are like this with or without WG Coil Mod while running. Is this the Dyna S Craping out (just down loaded some tests on the Dyna site) is it as simple as using Resistor Plugs? Thanks for any help.

Solid copper wires with non-resistor plugs and caps can cause meters to go haywire.

Woldwolf had PM'd me on this as I had erratic measurements as well using the provided inductive clamp. I went with the direct measurements using the probes instead, no problems then, steady reading...

Wolf, with your meters Black lead securely to ground (battery or frame if truly grounded frame) and insert the RED probe tip as in the image....

NOTE: The image pedicts my previous Tach, same principle.

Does the rpm still jump all over the place?

What # of cylinders do you have your meter set on?
This shouldn't cause erratic measurements, one setting vs. the other will just read higher than expected....

OMR

Hey Old Man Rock Thanks for chiming in. Yes even with the way you have pictured mine still jumps around crazy 350-1500rpm. OEM Tach steady at 1000-1050RPMs. I even have a old Actron meter like the one you have Pictured 20-25 years old. Hooked as pictured it holds steady at 250RPMs. I think it has lost its calibration. I think it should be closer to 500rpm. On the Mazda pickup the old Actron shows about 350-375 rpm about half of what I read with the Cen-Tech meter. Cen-Tech reads a steady 720RPM or (72 x 10). OMR are you using BR8ES Resistor or B8ES Plugs. What Kind or Plug wires are you using. I'm using Dyna 7mm solid Copper Core. Also if I check the DCV going to the Coils while Motor is running with the Cen-Tech DC reading is all over the place. If I use a old Analog meter the DCV at the Coil is a steady 12.5 vdc. Kind of worried maybe the Dyna is going out. Can you check the DCV to your + side of your coils with the Motor running and see if its steady. I will try to trouble shoot the Dyna S and Coils in a Day or so per the Dyna download I pulled from their site. I'm looking for another Digital Volt meter to check the DC with.

Thanks for the help.

"OMR are you using BR8ES Resistor or B8ES Plugs."
NGK B8ES, no resistor...

I obtained my complete Dyna S, 3 ohm coils and 7mm suppression core plug wires from Z1...

In my setup, I used exactly the same connections as provided in the image with both sets of Tach meters, same results.... Actually, the Cen Tech unit was more stable Digital versus Analog deflections...

Questions...

You did run through the complete procedure with a 12Vdc light for timing and adjusting the Dyna ignition plate correct?

Did you also try this on the feed to coil 2 & 3?

Are you using the frame or battery itself for the ground reference? Use the battery (-)...

You mentioned a very low RPM measurement... On a 900/1000, spec is 800-1000 rpm... Maybe I just miss understood...

In using the cluster tach, what is depicted in your analog tach (rpm )?

Does the motor seem to be running nicely, smooth idle, or erratic or rough as in missing, etc...

OMR

As can be reviewed in this clip, stable @ ~ 900rpm....

Hi OMR, thanks for the reply.

Questions. Yes went thru the complete 12vdc timing Light procedure on both 1-4 and 2-3. Timing is dead on. Thanks for the Tutorial, it works great.

Yes, using Batt (-) as Cen-Tech meter ground.

OEM Cluster Tach is reading a steady 1000RPM.

Idle is smooth.

My old Actron RPM/Dwell meter is steady but low about 250rpm on the scale. Meter is 20-25 years old and has been dropped a lot.

I tested the Coils and Dyna S today per the Dyna Website download and all Tests Good.

I will clean and lube the Advance Mech and Cam tomorrow. It felt a little sticky and slow to return when snapped over by hand.

Cen-Tech Meter seems to work find on the Mazda Truck.A steady 720RPMs. Not sure if its just picking up a lot of noise from the Plugs and the solid copper core Dyna plug Wires or what. Still exploring ideas. It seems odd that the old Analog meters Tach/Dwell and AC/DC volt meters have steady readings and the new digital does not on the KZ. Both Analog and Digital Meters read steady on the Mazda Truck. Thanks again.

If the engine is running smooth (idle), timing light test results good & since your OEM gear/cable driven tach depicts in spec RPM... I'd say good to go...

It is possible that the Cen Tech unit is defective... Take it back and get another one... As provided in my clip, clamp on is erratic, no doubt. In using the probes as shown in the image, steady readings so not sure why this is occurring....

Same time, we all need to keep in mind... HF tools are what they are... Cheap!... Yes, I buy them and use them for if only using once in awhile or just need this one time only, how the hell can you beat the price... Disposable...

If a mechanic and using daily/all day, no way, go spend the money required for snap on or in this case, FLUKE....

Hope it works out either way....

OMR

Non-resistor plugs with solid wires and non-resistor caps even make my several Flukes go haywire. You only need one of: Suppression wires, or resistor caps, or resistor plugs to alleviate the RFI.

Also, if the RPM/dwell-meter was for a car, then the signal will read very low, depending on how it's hooked up and what the meter is set to.

On my Sunpro (by Actron) dwell meter, in order to read dwell, I have to take the 8cyl scale and multiply by 8. Yes 8. That's because it's a 4 cylinder motor, but only reading the signal from 2 cylinders, and measuring crank dwell angle instead of cam dwell-angle (which is what cars use to measure dwell because the distributor rotation matches the camshaft).

To measure RPM, I take the 8 cylinder scale and multiply by 4.

BTW, the dwell on the Dyna S is very high... between 300 to nearly 360 degrees (of crankshaft rotation) which is why it draws so much current through the coils.

I have a new set of BR8ES plugs that I will try. My 20-25 year on Actron Tach/Dwell meter is for a Car/Truck. So If I was reading 250RPMs does that mean 250 x 4 =1000rpms. Will post results on the Resistor plugs tomorrow. Thanks again Guys.

Installed the BR8ES Resistor Plugs today and now have a steady idle on the Cen-Tech meter. Will look at getting a set of suppresion Plug wires also. Thanks Guys.

No, don't buy suppression plugs and wires. You need one or the other, not both. See the last post by loudhvx.

Right, you only need suppression wires OR resistor plugs, but not both. Too much suppression starts to affect spark energy.