Board logo

Anyone had issues with Acewell RPM reading?
the_fbi - 24/12/06 at 04:57 PM

Anybody else had an issue with the Acewell's not reading the RPM properly from the CDI?

The instructions say it can either be connected straight to the CDI or 3-5 turns around one of the coil leads.

I've connected mine straight to the RPM output of the CDI unit. It reads 2400 rpm for a few seconds then drops off to 0.

So I'm guessing it shouldn't actually be connected to the RPM output from the CDI as that just makes far too much sense! So I'm presuming it needs to be connected to one of the coil triggers from the CDI, but, given that there's only 2 of them, one for each coil with each coil driving 2 cylinders, surely I'll get double the RPM reading?

So looks like the only way is to do the 3 turns round an HT lead (but how does it know its a 4 cylinder?) but this is a bit naff.

So its possible this will actually read 1/4 the actual RPM as it'll presume its the HT lead to the dizzy, rather than a lead to the plug.

What's everybody else done and what should it be connected to?

ta
Chris

Bob C - 24/12/06 at 05:30 PM

How many coil packs you got? If you have 2, each with 2 HT leads, then you have a wasted spark system. The CDI tacho output will probably be 2 pulses per rev (would be right for a 4pot with a dizzy) - and that's probably what the tacho itself is expecting. A wasted spark system gives 1 pulse per rev so it would read 1/2 correct revs.
These things are usually adjustable (e.g. for 6 pots or V8s etc) so you should be able to find something that works..
Keep you busy over xmas.....
Bob

the_fbi - 24/12/06 at 06:05 PM

If you forget the paper "manual" which comes with it, and just use their FAQ online, it tells you how to change the number of triggers/rev.

I guess its an FAQ because its not in the manual!

I guess the rpm output is a bit lightweight for the Acewell which expects a proper 12v signal. I'll change the feed to one of the coil triggers tomorrow, change the Acewell to expect one trigger per 1/2 rev and all should be done!

Howlor - 24/12/06 at 10:12 PM

I had no issues on Fireblade although I did find that if the battery was not in tip top charge then the revs would go a little haywire.

I conneced it to the ecu output.

the_fbi - 24/12/06 at 10:19 PM

quote:
Originally posted by Howlor
I had no issues on Fireblade although I did find that if the battery was not in tip top charge then the revs would go a little haywire.

I conneced it to the ecu output.

The normal/proper yellow/green RPM output or the coil trigger outputs?

I've not changed my Acewell for the number of cylinders/coils/etc so perhaps thats the problem.

Howlor - 24/12/06 at 10:27 PM

The normal output. And then I think I had it set on 0.5.

Steve

the_fbi - 24/12/06 at 10:37 PM

quote:
Originally posted by Howlor
The normal output. And then I think I had it set on 0.5.

Steve

Thanks, I'll have a play in the morning. No idea what the default is.

hector - 26/12/06 at 02:37 PM

Hi
I had some nigglies with my acewell, basically i needed to use a shrouded signal wire.
I used a length of tv ariel wire and grounded the sheath wire to the chassis and wrapped the signal wire around the HT lead about 10-12 turns (the more wraps you do. a stronger signal you get)
I now get a much more stable reading as before i did all this it was picking up interference from the other car wiring!

cheers colin

the_fbi - 26/12/06 at 02:58 PM

quote:
Originally posted by hector
I had some nigglies with my acewell, basically i needed to use a shrouded signal wire.

I'd thought this too, although unfortunately all too late as my rpm wire is nicely bound into the rest of the loom.

I've got some more wiring to sort tomorrow so I'll run a completely separate wire from the CDI and see how that works.

macnab - 27/12/06 at 02:41 AM

I'd be happy if they would actually deliver the damn thing in the first place.