After sorting out other problems I am now stuck with rpm spikes.
They seem to be random spikes, not huge ones. They mostly just jump up one or two thousand rpm and cause a miss.
This is my setup
MS2-E_V1.02 firmware
13bt
Ignition only, leading only. 2 bosch hec715 coils COP.
MS1 v3 upgraded to MS2 with error* daughterboard.
Toothed cas.
220k pullup resister on D14.
Ignition out from D14 through pin 31 of DB37 to 2 VB921s on a daughterboard mounted on the outside of the case. One of the vbs spontainiously fried itself yesterday for no good reason but that's another story.
All the trimpots are turned anti-clockwise until the click is herd. Is there anyway to test these on the board? I put a multimeter across the 100k one and can only get a maximum of 35k.
The vr sensor wiring is two sets of twisted pairs each wraped in two layers of aluminium foil and then wraped in copper wire to form a braided sheild as best I could. The copper wire is grounded to one of the grounds at the db37. The whole lot it the shrink wraped.
I have jumped pin 5 and 8 on the second lm1815 in the daughtercard as per a post on the msextra forum and it improved things a lot. It is supposed to raise the treshold. Is there something similar I can do to the first vr conditioner?
I have also moved the vr sensors as close to the teeth as I can.

I am not sure what else I can do. I have checked everthing several times and rewired everthing and it has not improved.

Any ideas?

 

try putting a .01 uF cap across the G+ and G- inputs where they connect to your lm1815.

If that doesn't work, the noise is probably on the Ne signal, and that can be taken care of using the noise filter feature of the firmware.

Ken

 

The noise filter seems to have fixed the problem! I turn it on and there is no spikes/misses and I turn it off and they are back. I had tried the cap before and it didn't work. So this means that there is a noise problem with the ne side of the vr? Should I worry about it or just leave the filter to sort it out?

Also what settings should I use? I have it now set to 500-9500 and 0.00 usec for each.

thanks again for your help.

 

haha, at 0 usec for each, the noise filter's not doing anything at all!

Kinda funny.

I would just set it to 70-80 usec across the board... if you find that at this setting you still have noise at lower rpms, you can raise the lower rpm bins a bit.

It would be better to try to find the source of the noise, but if the noise filter is working for you, go ahead and keep using it.

Make sure you reboot the ms2 after enabling or disabling the noise filter though.

Ken

 

Thats wierd. I checked it again and 0 usec defiatly fixed it. I set them to 70 and the spikes are back. It misses every ten seconds. I set it back to 0 and it's perfect. It idled for more than ten minutes and still no spikes.

Very strange but hey it works. I went for a spin in it for the first time in weeks and it went great. Thanks again for all the advice.

Paul.

 

You can try adjusting the hysteresis potentiometer a little away from fully counter clockwise (meaning turn it clockwise a bit) to see if that helps your noise issues too. If you turn it too far you'll lose the signal at cranking speeds though.

Ken

 

hey guys, i am having a similar problem. how does one go about activating this noise filter?
sorry if this is a dumb question, i am at work and don't have access to Megatune at the moment, maybe this is just in a simple drop down menu?

 

The noise filter is a feature of ms2/extra 1.0.2.

If you're not using an ms2 with ms2/extra on it, you probably won't be able to find a menu for this feature.

If you are running an ms2, it is in the "advanced" section I believe.

Ken