Stage 6 Mini LCD Thermometer

Just fitted a S6 mini LCD temp gauge to an aerox.

4 wire job, switched positive, ground, and two wires to the cylinder head temp sender.

Seems to give accurate temp. Sat with motor off , it read room temp, but as soon as engine is started, both the display and backlight flask /flicker randomly. No temp displayed.

Stop motor and put ignition back on, and displayed temp shows increase.


If I disconnect the sender from the display and run the motor, the display is perfect.

Tried, powering the display from as seperate big car battery, off the bike, disconnecting the rectifier/regulator in case the AC /DC Reg was causing noise...Still no joy.


Anyone else seen this behaviour on one of these ?

If I disconnect the sender from the display, and run the bike, then display is stable.
So it seems sender is picking up 'noise' and causing the display to fail. CDI / ignition issue ?




See video

 

Can you post the instruction sheet please?
Doesn't seem right to have 2 wires to the temp sensor.

 

OK, I will do when I get back to the workshop,

But it is the sender that came with it, and the original wiring from sender to head unit is all plug together with black mini multipin plugs.

The instruction sheet is a single A4 sheet showing multiple different sender types.


I did check the sender resistance to ground and between the pins.
13.21 when cold dropping slowly as motor warmed up. Never ran motor for more than 30 seconds to a minute in the shed, but in that time it dropped to about 11 Ω . and when motor off, display of about 32deg C

 

99.999% sure this is the same as the one supplied

http://www.pedparts.co.uk/c/asset/Stage6_Instructions/S6-4033xx_EN.pdf

 

But definetly wired correctly with what was supplied.

Faulty sender maybe, noisy ignition . maybe some ferrite rings or capacitor to ground on sender feed.

Even wondered about vibration of the display when engine running, so took the display off the bars.

Display only goes weird when temp sender connected and engine running

 

Looking at the diagram, I suspect you've tapped into the wrong positive wire off the back of the ignition switch.
The display looks like it's picking up the pulses from the coil or plug circuit from the way it flashes.
Does it get quicker when you rev the bike at all?
Have you used the optional water temp unit?
Have you used the spark plug option? (Which might explain the pulsing)

 

I did wonder about noise on the power line too.

So I connected the power to a totally seperate battery, a car battery off the bike.

But still the same issue.

I then took another pair of wires off the sender, and took the display off the bike. So only contact to the bike is the sender in the head, with no wiring connection at all, apart from the two wires going to the sender.

Not yet tried other senders.. I'll have to see if it came with others when I see the owner later.

 

Could it be an earth problem on the scooter?

 

Was thinking along the same lines Gil.
Maybe try connect both + and - to external battery, then connect sensor and see what happens that way.

 

I was thinking a faulty sender. Having 2 wires would imply it's not earthed through the engine.
Pity it's not the type that is in the water hose as it would be insulated.
It's the sort of fault you sometimes get with brake/indicator lights if they have a bad earth as they usually take the shortest path and light up a sidelight?
If you have a jumper cable earth the engine straight to the battery.
You seem to have isolated the display from the scooter with the same result so the only common items are the engine/sender.
Could you try the sender on something else?

 

Already tried that, running external battery to the LCD.

Don't have any other sensors.

Have just cut the sender supplied wire, right back to the sender and used shielded Co-Ax cable. with the screen both earthed to chassis and via a capacitor.

Still LCD flashes in time to spark.


Though I had found the problem, the just out of the box Stage6 Coil/HT lead and cap... the cap came off in my hand, was not screwed in to the HT lead securely.... but no. Fixed that and it still pulses.

motor to chassis/battery earth all good too. A totally ground up rebuild, all resistances to near as damnit zero ohms.

Not got a different sender to try, but I do have some random thermistors, might try one and see if it still 'faults' with another temp sending 'device'

 

No I meant could you try the whole thing on something else using a remote battery and swap the sender over?
I just thought if the sender worked on something else it would discount the sender so the fault had to be the scooter?

 

Ah yes, got you.

I have found a 15k thermistor, and rigged that up. Same range as the original temp sender. Still flashing, when the 'flying lead' with the thermistor is brought up to near the cylinder head


The engine to chassis /battery earth... Just checked that .... ooops. 1.2kohm. Created a quick jumper cable to create proper earth and that did not help... but a fully bolted earth needed anyway. When Dave ( bike owner) built it up, he has dispensed with electric starter..., so no earth now. That may explain the lack voltage increase at the battery when engine running too.

Will crimp up new engine earthstrap and report back

 

If it still doesn't work try putting a radio near it as it sounds as if you may have a suppressor problem?
I'm not well up on electrics these days but I understand some plugs have inbuilt suppression whereas others have it in the cap?
So you may need either a suppressed plug or cap but not both if that is correct?
You may have an unsuppressed plug and cap?
If you still have the old ign system it may be worth swapping it over just to try it?

If all that still fails you could always try and fit the sender away from the head nearer the radiator using a hose adapter?

 

Sounds right.
The plug is straight B9, not a BR9 resistive type. Could be that.

All new Stage 6 coil/lead/cap and plug.

 

Just found this read the second paragraph
http://www.sip-scootershop.com/en/products/spark+plug+ngk+bpr7hs+copper+_ngkbpr7hs0

 

I've found more posts on the rev counter where it says to use a resistive plug as well as the cap so that might well be it?

 

im gonna go with resistive plug and cap , its a hell of a lot cheaper than an ignition chop.

i know the diatech scoots had to shove a 10k resistor on the rpm pickup wire to stop them being wildy out to. but they were not seeing the dash light flicker problem your getting

 

Cheers.
Will get the owner to get one today

Shortening/routing new clock wiring now.

Will see how it goes with the new earth strap, screened cable and capicitors to 'bleed' the interference to ground

 

Fitting an 'R' spark plug and it is all now working perfectly

Thanks guys