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Old 10-02-2020, 01:20 PM   #1
mrlaser
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Default engine analyzer questions

I have an old Craftsman engine analyzer that is for 12 volt systems. I am wondering whether this can be used on a positive ground 6 volt system if a separate 12 volt battery is used to power it? I am particularly concerned whether the pictured connection to the coil can be made. Any help would be appreciated. This was a very common testing instrument, so I am hoping that someone might have already have had this issue.
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Old 10-02-2020, 01:40 PM   #2
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Default Re: engine analyzer questions

Two more pictures regarding the recommended connections. The pictures were cropped to be small enough to upload here.
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Old 10-03-2020, 09:38 PM   #3
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Default Re: engine analyzer questions

I had one, very similar to yours. I believe it was made by Aacron. I tried to do what you are suggesting and it didn't work. I will admit that I quit then because I didn't want to damage it. I bought a universal (unpowered) dwell meter on eBay and went with that instead.
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Old 10-04-2020, 06:25 AM   #4
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Default Re: engine analyzer questions

Thanks for your reply. That is my concern. I was hoping that others might have tried to use of the analyzer and had some information regarding their success or lack thereof.
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Old 10-04-2020, 10:42 AM   #5
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Default Re: engine analyzer questions

I have what appears to be, the same one, but I usually power it with a 12 volt battery, next to the car. For dwell I use a handheld unit, it is just easier.
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Old 10-04-2020, 10:49 AM   #6
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I have a Snap-On Dwell-Tach and I connect its yellow wire to ground (6v positive) and its black wire to the distributor side of the coil. Works fine. Now as to yours, you do not need a battery to use the dwell or tach functions - connect yours to the distributor side (green) of the coil and ground (Black) and that should give you dwell and tach readings. The remaining wire from your instrument (red) is for determining system voltage - generator or alternator. I assume you are working with a 6v positive ground system. In summary, connect the green wire to ground and the black wire to the distributor side of coil and this should give you dwell tach. The dwell tach function measures across the points (positive ground and points (coil side. I had to reverse the wires on my Snap-On - yellow to ground and black to distributor side of coil. Should work - give it a try. You are not putting battery voltage to tester at this point. If that works, connect the red wire to the neg of the the 6v battery. Yes, the red wire is always positive, but see what happens when the green wire is connected to ground - positive-to have the dwell tach operate. Remember, we are dealing with a positive ground system (6v) and the red terminal is only for measuring voltage and your meter will read 6v - do not need a 12 volt battery. Confusing? Positive ground requires the reversal of the green and black wires.
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Old 10-05-2020, 06:40 AM   #7
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I think that I understand and will give it a try. Thank you for your information.
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Old 10-05-2020, 01:31 PM   #8
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I connected the black lead to the distributor side of the coil and the green lead to a ground. Attached that way with the engine idling, and the selector in the 8 cylinder position, the needle did not move from the "zero" position. When I moved the selector to the dwell position the needle moved to the "open" position on the points scale. There was no needle variation when the RPM was increased off of idle. Incidentally, I also reversed the black and green wire hookup which resulted in a neg deflection of the needle. Would you have any other suggestions? Thank you.
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Old 10-05-2020, 01:40 PM   #9
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Default Re: engine analyzer questions

Try using a 12 volt source to power it, then do the normal hook up. I will watch for your reply, if that doesn't work I will do a video on mine (since they appear to be the same unit), and post it.
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Old 10-05-2020, 02:36 PM   #10
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Default Re: engine analyzer questions

Two 6v batteries in a twin pack = 12v. Very handy and available at Wal-Mart.

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Old 10-05-2020, 04:31 PM   #11
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As I stated initially, I had to reverse the leads on my Snap On unit because of the positive ground system. You tried!!! I have no more ideas. I was not aware that a dwell-tach had to have battery power. I thought that the only reason that your unit used a battery was to determine system voltage. My Snap On does not need a battery. I am interested in your progress in getting your unit functional. Keep us posted!!!
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Old 10-05-2020, 08:31 PM   #12
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Default Re: engine analyzer questions

The point resistance scale is only one scale on the analyzer and is disregarded when using other functions. Look toward the top of the meter and see the "8 cyl, 6cyl, and 4 cyl" scales with "dwell" off the the side.
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Old 10-06-2020, 12:58 PM   #13
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When I connected the black lead to the distributor terminal lead on the coil, with the selector set to the 8 cyl to the tach setting, or the dwell position, and the green lead attached to ground, the needle did not move at all. When the selector was moved to the points position with the same connections, the needle moved approximately 3/4 of the way to the opposite end of the scale which fell in the "open" part of the point scale. As I mentioned, there was no change in the needle position with actual changes in engine RPN. I'm not sure what this " reading " represented. I will try this with a spare 12 volt battery soon and report back. Thank you all for your advice and help
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Old 10-06-2020, 01:01 PM   #14
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Sorry for the double post. Necessary due to picture size.
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Old 10-06-2020, 01:39 PM   #15
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Default Re: engine analyzer questions

Same thing that happened with mine. As I said, then I quit so I wouldn't damage anything. (I do have some 12 volt vehicles I work on.)
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Old 10-06-2020, 07:39 PM   #16
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What result when you connect the black lead to ground and the green lead to the distributor post on the coil? To check point resistance you need a battery connected to the unit. Same for voltage checks. Checking point resistance is the same as an ohm meter - need battery.
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Old 10-06-2020, 08:23 PM   #17
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Default Re: engine analyzer questions

Nothing that I tried was successful. I later found this very informative discussion. I am including it for those who have contributed to this thread. Thanks to everyone.

https://forums.aaca.org/topic/328679...do=findComment
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Old 10-06-2020, 08:26 PM   #18
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https://forums.aaca.org/topic/328679...gine-analyzer/
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