The reed switch on my acewell became a bit intermittent, I rather objected to paying the inflated acewell price and used one of these, worked perfectly....
I've got an Acewell digidash fitted to my car which was faultless until recently when the speedo reading started jumping about, suddenly showing
nearly twice the actual speed, then back to normal, then something like 7MPH... it's all over the place. the speed sensor is at the diff input
flange, with the magnet on the flange. It's all still mounted securely and there's approx. 5mm gap between the magnet and the sensor. The
magnet centre isn't perfectly inline with the sensor but it's only a couple mm out, I can't imagine this would cause this issue and it
would have been like that before when it was working fine.
Any ideas what could be causing this sudden erratic behaviour?
[Edited on 20/8/15 by russtik]
hows it wired up, where is it getting its source from?
It's just a simple reed switch, 2 wires (earth + feed from digidash).
Is the reed switch in the correct orientation in relation to the magnet - the magnet should pass the end of the reed, i.e. the short side opposite the
wire, not the longest side. Getting this wrong can cause the speed doubling effect you mention.
The reed switch on my acewell became a bit intermittent, I rather objected to paying the inflated acewell price and used one of
these, worked perfectly....
This is the type of switch I have, the magnet passes the tip.
That's a different type to the one fitted to my unit which looked just like the one shown in the link. I'm not sure if the two types are
interchangeable.
The issues you mention all sound like a sensor issue though.
Wiring/connection issue would be my first suspect.
Over reading to me indicates a connection making and breaking under vibration or movement. As with ABS sensors tracking this type of fault is a lot
easier with an even a basic oscilloscope.
quote:
Originally posted by britishtrident
Wiring/connection issue would be my first suspect.
Over reading to me indicates a connection making and breaking under vibration or movement.
Let us know how you get on. I've been putting off resolving this issue on my car too (also acewell and same sensor as you)! I've been prioritising other things but this is now next on my list whenever I get a couple of hours to play with the car.
FYI, speedo worked a treat on the striker before i changed the prop (never got round to mounting it correctly.
Just try and make sure you've got a nice solid bracket for the sensor, and that the magnet is passing very close (within a few mm max) and again,
mine worked a treat! Hope this helps.
Also, there are some interesting settings on the acewell that if you get wrong will give ridiculous readings so worth a good read of the manual
To do what you describe it pretty much has to be either a connection making & breaking or the sensor itself failing.
I would suggest check all connections in the path between sensor & Acewell, if nothing obvious then with the car stationary & engine off, so
no vibration, remove the sensor & run a magnet back & forth past the tip, this should generate a speed signal which will vary with frequency
depending how quickly you move the magnet back & forth. If the reading is consistent then the sensor is almost certainly ok, if not then probably
sensor fault. Assuming sensor appears ok get someone else to wiggle all the wiring & connections to see if you can simulate the fault, might
point you at the correct bit of wiring to examine/replace.
If it does prove to be a sensor we have them from stock
quote:
Originally posted by pekwah1
FYI, speedo worked a treat on the striker before i changed the prop (never got round to mounting it correctly.
Just try and make sure you've got a nice solid bracket for the sensor, and that the magnet is passing very close (within a few mm max) and again, mine worked a treat! Hope this helps.
Also, there are some interesting settings on the acewell that if you get wrong will give ridiculous readings so worth a good read of the manual