flanders
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| posted on 18/12/16 at 05:48 PM |
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New gauges are 'twitching'
So I fitted nice new gauges (volt, oil press, oil temp) in my dash, they look great but are very erratic and 'twitchy' when the engine is
running, fine when the engine is off. I'm assuming they're picking up some kind of electrical interference somehow?
The Earth is good and so is the positive. Voltage is stable with in a few mV and everything else works fine.
I'm wondering if they maybe don't like the motorbike engines charging system?
Any help on this would be great.
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mackei23b
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| posted on 18/12/16 at 06:26 PM |
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Might be worth putting in a 12 volt stabilizer for the gauges?
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flanders
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| posted on 18/12/16 at 07:19 PM |
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Yeah I could try that cheers.
Just seems strange and I'd like to resolve the issue if i can.
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bi22le
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| posted on 18/12/16 at 07:32 PM |
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How fast do they twitch, is it a wave or erratic?
What happens when you rev the engine?
If your previous gauges were fine it can only be supply to the gauges. So run direct pos and negs.
What else have you changed? Maybe you have lost an earth elsewhere and this is back feeding on the sensor supply causing issues.
If the three gauges twitch at the same time in the same way ot can only be the wiring that is shared by all of them.
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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flanders
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| posted on 18/12/16 at 08:33 PM |
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The gauges share the same supply and twitch totally out of sequence with each other, and revs make no difference.
I've also ran them straight off the battery posts which seems to help a little and I've tried them Individually but they still do it.
They're totally fine without the engine running which is what's confusing me and making me think there's interference on the system.
The twitching seems to be totally sporadic
I didn't have gauges there before.
Strange one...
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mackei23b
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| posted on 18/12/16 at 08:44 PM |
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As a test how about powering the gauges from an indipendant power supply / second 12v battery? That would tell you if there was issues with the
supply?
As a further thought, do you know if the gauges are measuring the change in current, resistance or voltage?
Cheers
Ian
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mcerd1
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| posted on 18/12/16 at 09:54 PM |
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what kind of gauges are they ?
-
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flanders
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| posted on 18/12/16 at 10:09 PM |
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These ones fella... volt, press and temp. They read correct until the engine running, then the needles randomly jump
https://www.ebay.co.uk/itm/261549741018
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RedAvon
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| posted on 19/12/16 at 08:58 AM |
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Hi,
These gauges are driven by dc stepper motors. Check the route of the signal wires from each of the sensors to make sure they are not near other cables
or electrics that may induce unwanted pulses into the signal wires. Also, check whether there is any adjustment options for sensitivity.
Hope that helps.
Ian
Bricoleur
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steve m
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| posted on 19/12/16 at 09:41 AM |
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Your gauges, do not seem to state that they need a voltage stabilizer , (as mine doo, as the old smiths type)
So unfortunately, it may be a wiring issue, or as said above, something close that is causing a spike
How close is the coil, or any other ignition circuit to the sensors or gauges ?
Do they twitch when cranking over, but ignition off ?
Have you tried disconnecting one gauge or one sensor at a time, as it could just be one, but affecting the others
steve
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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flanders
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| posted on 19/12/16 at 10:17 AM |
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Thanks guys
the signal wire for the oil press gauge runs in a conduit with my left hand indicator and another oil press signal wire.
I understand about signal interference but a volt gauge shouldn't be affected by this?
they're not near any ignition wiring as such but the gauges themselves are close to the ECU??
I may have to try some screened cable
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nobby_the_sheep
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| posted on 19/12/16 at 02:07 PM |
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Make sure your engine earth strap is in good condition / no volts dropped across it 
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flanders
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| posted on 19/12/16 at 02:30 PM |
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quote:
Originally posted by nobby_the_sheep
Make sure your engine earth strap is in good condition / no volts dropped across it
I did try extra earths on the engine, made no difference.
My earth path is battery-engine-body
I'm very weary of running small cables/circuits direct to the battery posts as a failure of the main Earth cable could mean big current running
though these small conductors
[Edited on 20/12/16 by flanders]
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flanders
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| posted on 19/12/16 at 06:13 PM |
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Ok so update
If I run the gauge directly from the +\- on the battery they're way way better, still a very slight twitch but not much so it's
definitely interference in the wiring. I also connected them up 15ft from thecar and the still did it. Also it is worse with more revs
Is is there any device I can use to filter the interference out?
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flanders
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| posted on 19/12/16 at 10:08 PM |
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Gave up trying to sort it
I've ran the gauges via a fuse and relay from The battery, the work perfect. It'll do for now while I crack on with the rest of my build..
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