1976 FJ40 2F Semi Transistorized Points Igniter…Dwell measurement? (1 Viewer)

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Ackcruisers

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I’m not able to get dwell or RPM reading on my new multimeter (performance tool, W2972).

How to connect black (COM) and red test leads to my 89620-60010 coil/ignitor? The manual says to connect RED test lead to negative post on coil and the BLACK (COM) lead to ground.

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Does your distributor still have points?

Per downloaded manual:

"1. Insert BLACK test lead into COM test lead jack.
2. Insert RED test lead into test lead jack.
3. Connect RED test probe to the negative terminal
side of the primary ignition coil."
 
Humm, my HarborFreight CenTech manual also has an induction signal pickup for high tension lead to a spark plug, different paper, same box. The signal pickup is for dwell and rpm...
 
Yes @B y r o n I am running new points with new non USA OEM distributor.

This is how I’ve set it up the meter (per instructions). It provides no dwell reading or rpm. (The unit is off in photo).

It makes no sense to me how RPM can be measured without probe being connected to plug wire.

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The coil only discharges when the dizzy points are closed, so just like a tach your meter should be sensing this rate and duration (dwell) of each discharge. Since your meter does this with built in functionality it doesn’t need an induction reading probe which would connect to a plug wire. Also why your meter (PT) is more expensive than others 😂. Make sure red is connected to the negative terminal of the coil, and the black to a chassis ground.
 
The coil only discharges when the dizzy points are closed, so just like a tach your meter should be sensing this rate and duration (dwell) of each discharge. Since your meter does this with built in functionality it doesn’t need an induction reading probe which would connect to a plug wire. Also why your meter (PT) is more expensive than others 😂. Make sure red is connected to the negative terminal of the coil, and the black to a chassis ground.
Yes the $35 PT tool is not the best choice…I need to make the investment in a FLUKE multimeter. My Extech 430 works well but it did not measure dwell or tach. I connected the red to the negative coil post and black negative to chassis ground. No tach or dwell reading. I’ve got a call into the electrical engineer at PT.
 
Posting the 8/80 2F FSM Engine Repair Manual (pub. No. 36401E) details on Tach and Dwell. It says “some tachometers are not compatible with this ignition system”…it may be my new PT W2972 multimeter with tach and dwell…

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Maybe it is the igniter that is giving you the issue? If you reinstall a capacitor on the distributor, and bypass the igniter, you might have what is needed to check dwell. The Haynes manual describes the hack, which is really odd for a repair manual that includes emissions info.

I'm pretty sure that I used the induction hookup on my CenTech multimeter when I checked dwell and idle rpm. I can perform a check tomorrow to see if I can replicate some data, and if the non-induction method described for my multimeter will also not do a reading if the igniter (probably a '75) is hooked up? Let me know if that would help.
 
Yes, @Grayscale that was my initial reason for posting. I thought the Ignitor circuitry was interfering with the multimeter signal. The Haynes hack is likely a good test for me should the ignitor every fail. Now I’m determined to get a dwell reading to see if I’m within spec. I’m including the 0.22 mfd condenser image below. It says to connect this to the distributor body terminal and ground.

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If you are running an 89620-60010 it would be great to know if you can get dwell with your Cen-Tech 95670 multimeter by connecting it as shown in your manual below.

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@Grayscale …I just got off the phone with the electrical engineer at Performance Tool. There is a known issue with the W2972 digital automotive multimeter. It will not provide accurate dwell or tach.

Thanks for everyone’s help on this.

I‘m in search for a reliable multimeter that has tach and dwell capabilities…
 
@Ackcruisers is that with all coil/dizzy setups or just with your lineage of ignitor/coil/dizzy setup? What a crazy world, acknowledge your product is faulty yet still sell/market it. 😳

(I actually went through this with Magnadyne on one of their RV radio/dvd/stereo units. They now all work because I found an obvious fault in their embedded code. Engineered in US, built in China. Ding ding ding 😂)

Hopefully you find one at a decent price and can share the info! Thanks!
 
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If you can find one, get an old analog dwell/tach meter ( kind with a needle) . I had the same issue (77 with original ignition set up) as you with a different make.
 
I just did a dwell check in the rain, almost snow. It says that my factory points that have never been touched have a dwell angle of 42 degrees. I did the COM lead to battery negative and the red lead to the negative post on the ignition coil. I failed to get a part number for the igniter that is part of the equation.
 
@middlecalf …the engineer never even got far enough to hear me explain what my semi electronic igniter does. He immediately said there is an unfortunate known issue with dwell that will not provide accurate reading and to return it. In my view, they figure many customers will not try and measure dwell anymore since points are few and far between. It may also be the reason the multimeter was so inexpensive… $35 😂

@Grayscale, thanks for checking your multimeter reading. How old are your points? 42 is right at spec.

I do know one of the benefits of the 89620-60010 igniter is that it makes points last a very long time. So, even if your points are older, the 42 dwell angle may be accurate.
 
I gave myself a Fluke 88 for Christmas. Just like this one:

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Yes, it's more spendier (word of the day) than the PT W2972 (which I gave to my boys for their Land Cruisers, which aren't 40s), but it also works.
 
@Grayscale, thanks for checking your multimeter reading. How old are your points? 42 is right at spec.

I do know one of the benefits of the 89620-60010 igniter is that it makes points last a very long time. So, even if your points are older, the 42 dwell angle may be accurate.

I installed that distributor about six thousand miles back. It was the earlier one that CityRacer offers.

I wonder how far off you have to be with just setting the points with a feeler to have an impact on dwell? I recall that distributor cam wear has been described as a factor that can help you get dialed-in with your points setting, somewhere here online.
 
I could not justify the Fluke 78 multimeter…ended up buying Innova 3340 For $99. The unit came with the spark plug induction signal pick up. NOTE: The rpm fluctuated more wildly vs. my Innova 3568 timing light…

After more research, the igniter is what controls the coil so it will measure the current draw so as to not interfere with points dwell measurement. My measured dwell angle was 31.2…out of spec. I needed to increase the gap.

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Did you try and use the coil connections to get rpm?
 

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