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Registered:
February 2005
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Hooking up rpm gauge?
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Fri, 25 November 2005 19:50
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Hi
I got myself a digital led rpm gauge today, and from the manual that comes with it, it seemed to be a very simple instalation, but of course,it wasnt that easy.
earth and switched power is fine, and the tachometer works fine, until i do as the manual says and hook the signal wire up to the coils - point, then everything gets weird, the lights in the tachometer starts flashing and shaking, and the rpms is at 0, but once in a while, it reads some weird rpms, like 9000 or 4576, just for a sec, and then it goes back to 0 again.
it could seem like the coils negative isnt the right place to hook up the signal wire, or maybe the gauge is defect.
the car has not electronic ignition.
does someone know whats wrong?
thanks in advance
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Location:
Menai area of Sydney
Registered:
June 2003
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Re: Hooking up rpm gauge?
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Fri, 25 November 2005 21:06
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See if you can get a lend of someone's dwell/tacho car tune-up meter that you can get from car parts places and connect it up to see whether the tacho readings are OK. If they are then your meter is probably dodgey. Make sure you have a good earth as well as some of the electronic gauges are pretty sensitive to electrical interference such as you get from spark plug leads, alternators etc.
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Registered:
February 2005
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Re: Hooking up rpm gauge?
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Fri, 25 November 2005 21:28
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Hi
im far away from wherever i can borrow a tacho reader, so thats not really an option, but i know for sure the readings my tacho gave very not correct, since the car was ideling all the time, probably somewhere around 6-700rpms.
i also tried hooking power and earth up directly from the battery, but its still the same problems.
one thing i thought was strange that the negative point on my coil carries around 7volts, does anyone know if this is normal? i thought it should be just earth there.
is there anywhere else on my car i could get the signals i need?
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Location:
Pine Rivers QLD
Registered:
April 2005
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Re: Hooking up rpm gauge?
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Sat, 26 November 2005 03:42
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Just making sure this wasn't a kit?
If you did buy it then i have found them to be very touchy, like if you don't wire it properly the first time then it breaks.
Cars are very different and their tacho lines also vary from car to car, if you used a digital multimeter to read 7 volts then that is not correct, if you rev the car up you may find the voltage will increase, this is due to the signal on the -ve side not being DC and thus an "average" is detected. if it was me i would knock up a square wave signal generator to test it but failing that, i would maybe try it on someone else's car if possible.
But as you said the manual is fairly simplistic and thus it is likely that the gauge may be faulty.
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Registered:
February 2005
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Re: Hooking up rpm gauge?
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Sat, 26 November 2005 03:54
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Hi
It wasnt a kit, as least as far as i know, but it seems to be a piece of crap, cuz now something happened to it and now its just glowing instead of the light that was there earlier.
i contacted the seller, and he said maybe the tacho wasnt ment for cars without electronical ignition, but in the manual it says to connect either to coil or electronic ignition. so im guessing it really should have worked on my car too then? any thoughts about this?
is it possible that it can be something wrong with my coil/car so thats why it wouldnt work?
i thought it should be very simple to hook up the signal, never heard of that going wrong before, i wonder if i should buy another tacho now, or do i risk the same thing happening all over again?
is there anything i can do to make sure the negative end on the coil is ok, cept for getting a rpm meter from a mechanic or something?
thanks again
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