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Re: Low Z noise problems

Posted: Sun Dec 13, 2009 1:38 pm
by B-lennium
I had a very irritating voltage spike, the voltage spiked to 17volt and to 6 volts, i could feel it in the car wile driving (same as a burn) (MSII msextra 2.10)

I did the injectordriver separate 12volt wire. this did't cure the problem.
then i tried the 220nf cap on the H1 position...

And away went my spiking!

I fixed it with a 12cent part!

Re: Low Z noise problems

Posted: Mon Dec 14, 2009 4:32 pm
by BenGTT
B-lennium wrote:I had a very irritating voltage spike, the voltage spiked to 17volt and to 6 volts, i could feel it in the car wile driving (same as a burn) (MSII msextra 2.10)

I did the injectordriver separate 12volt wire. this did't cure the problem.
then i tried the 220nf cap on the H1 position...

And away went my spiking!

I fixed it with a 12cent part!

Hello, I did the same a few days ago since I have switch from high impedance injectors to low impedance.
I had noise and then starting to try 10nF, then 33nF, 100nF. With 100nF voltage was perfect but sometimes it was dropping to 7V but no peak anymore. Then I tryed a 330nF and this time it was the good one. incredibly stable.
I think it is one of the BEST solution for MS2 with low Z injectors.

Re: Low Z noise problems

Posted: Tue Dec 15, 2009 8:33 am
by Safir
Just to be sure I'm getting this right, you're putting a small capacitor in place of the boot header on the V3 motherboard? are there any other moifications to be done first?

I have very low impedance injectors (~1.2ohm IIRC) and have voltage spikes like you describe, if this can smooth those out it would be great.

Re: Low Z noise problems

Posted: Tue Dec 15, 2009 8:52 am
by Peter Florance
Safir wrote:Just to be sure I'm getting this right, you're putting a small capacitor in place of the boot header on the V3 motherboard? are there any other moifications to be done first?

I have very low impedance injectors (~1.2ohm IIRC) and have voltage spikes like you describe, if this can smooth those out it would be great.
I found 47uf 35v from center leg of Q3 to center leg of Q9 works well. Negative lead to Q3.

Also running alternating instead of simultaneous.

Re: Low Z noise problems

Posted: Tue Jan 26, 2010 12:49 pm
by svocapri
I am having the low Z noise problems as well. So far I have done the flyback mod and ran the 12V middle leg back to the injector positive. Also I put a car audio noise filter on the power input going to the Megasquirt. My Innovate WBo2 is still having noise problems. I am wondering if I would do better to put the noise filter on the 12V lead to the injectors to help keep the noise from the flyback out of the rest of the system instead of just filtering the 12V to Megasquirt? Can anyone confirm that this is not a misconceived notion and might improve the noise to the Innovate? I am also curious about the capacitor on the boot header mod. How does this work?

Julian

Re: Low Z noise problems

Posted: Thu Jan 28, 2010 1:35 pm
by ryniobl
Hello everybody It's my first post here :)

Here is my way to get rid of noises.
I made it in my 91 Accord with PnP MS2

1.connect pin28 DIRECTLY to batt positive pole (use relay).Don't connect anything else to this cable.
2.lift TIP125 middle legs and connect to IGN 12V
3.lift FQPF30N06 , IGN and IDLE drivers right legs ,connect them together outside of MS to the GND
4.connect sensors GNDs directly to 2nd leg of onboard MAP
5.WBo2 in my case LC1 CAN'T be connected to sensor GND.It injecting a lot of noises due to heater PWMing
6.now you can throw away all of those filters and capacitors.

log before mod

http://picasaweb.google.com/ryniobl77/M ... 2503591346

log after mod. notice BattV scaling 8)

http://picasaweb.google.com/ryniobl77/M ... 3352201522


Good luck
Hope you could understand my poor english

Richard

Re: Low Z noise problems

Posted: Thu Jan 28, 2010 6:11 pm
by Black99rt
Do you have an LC-1 with a seperate sensor and heater ground? Is there noise on the sensor ground wire?

Re: Low Z noise problems

Posted: Thu Jan 28, 2010 8:13 pm
by svocapri
I do have the LC1 with seperate heater and signal grounds. The manual specified to bond the two together and ground them in unison, which I did.

Re: Low Z noise problems

Posted: Thu Jan 28, 2010 10:34 pm
by Philip Lochner
I've also had noise issues on my V12 Jag with LoZ injectors.

I also run the centre legs of TIP125s directly back to the injector 12V feed and have a 4.7uF cap in the bootloader position. This has made my PW remarkably stable.

If there is going to be a V3.1 or V4 board, this board should also allow for continuous barometric correction components.

Re: Low Z noise problems

Posted: Fri Jan 29, 2010 12:47 am
by ryniobl
Black99rt wrote:Do you have an LC-1 with a seperate sensor and heater ground? Is there noise on the sensor ground wire?
LC1 heater GND i have connected to the chassis,and sensor GND to the main MS GND (not sensor GND).If you connect LC1 sensor GND to MS sensor GND ,turn IGN on and make datalog,you can see PWMing noises in TPSacc and MAPacc .
Richard

Re: Low Z noise problems

Posted: Sun Jan 31, 2010 4:12 pm
by Black99rt
Thanks for the clarification, I'll make sure to do it the same way you have.

Re: Low Z noise problems

Posted: Tue Feb 16, 2010 2:42 am
by Perkele
I'm plannig to make all the possible noise reductions just to be safe but I was wondring can there be any negative effects in this?
For starters I'm plannin to put 1uf caps paraller to D3 & D10 and the 4.7uf cap to bootloader. And I'm also curious how will the bootloader cap work as a filter for the 12V when it's connected between GND and PP5/KWP5 pin on the MS2 CPU?

Re: Low Z noise problems

Posted: Tue Feb 16, 2010 5:07 am
by Peter Florance
I've been dyno tuning a TR8 this week (8 low z injectors)
The injector noise has been very low.

47uf 50v cap from center leg of TIP42C to TIP125
That's all I ever do for low Z injectors. I do a lot of jobs with 6 injectors. First V8.

I do above and provide plenty of ground wires.

Re: Low Z noise problems

Posted: Wed Mar 17, 2010 6:05 am
by elaw
Hey all, just thought I'd throw this out... this noise issue is definitely *not* limited to setups using low-Z injectors!

I'm using high-Z injectors and below you can see a log I made a while back... even though the battery V is on a fixed scale (10-16V) you can see it's very noisy. I put a cap in the boot jumper position on the V3 board and while I haven't had time to make another log, I can tell you the voltage is much more stable!

Edit: just to be clear, I do NOT know whether this noise is internal or external to the MS box (or both). Hopefully in the next few days I'll be able to go on a hunting expedition with a 'scope and answer that question.

Re: Low Z noise problems

Posted: Fri Jun 18, 2010 11:00 am
by Southcross
I've been looking at doing this mod with my v3.57 board... I've got the usual noise and random "spikes"

but have some questions

In-Line Stereo Power Filter vs Soldered-on Capacitor?
With everything being surfacemount on the v3.57 board, is there a way to accomplish mounting an onboard Cap "filter" (for a not-so-technical electronics person... I bought the v3.57 to minimize the agony of trying to solder a whole board LOL)?

Re: Low Z noise problems

Posted: Sat Jul 03, 2010 8:42 am
by kubeq_sq
hello, i have some other question about the low z inhjectors... i have read in the mextra manual,that if i use wasted spark i can't use low z injectyors... is it true??i would be very thankful for Your reply even though it isn't connected directly with the topic.

on the other hand i made the mods needed to have stable vbatt when using low z injectors and we will see, what i will get in the log when i connect my low z ijectors. just need to know if i can :)

Re: Low Z noise problems

Posted: Sun Aug 01, 2010 9:39 am
by decs
i've set up 5 cars now with wasted spark and low z injectors. not being able to do so is certainly news to me.

Re: Low Z noise problems

Posted: Wed Oct 13, 2010 9:51 am
by svocapri
Peter Florance wrote:
Safir wrote:Just to be sure I'm getting this right, you're putting a small capacitor in place of the boot header on the V3 motherboard? are there any other moifications to be done first?

I have very low impedance injectors (~1.2ohm IIRC) and have voltage spikes like you describe, if this can smooth those out it would be great.
I found 47uf 35v from center leg of Q3 to center leg of Q9 works well. Negative lead to Q3.

Also running alternating instead of simultaneous.
Since I have lifted the center leg of Q9 and Q12 to run to the injector 12V feed, if I use your mod, should I connect the 47uf capacitor between Q3 and Q9 or between Q3 and the now empty hole for Q9?

Julian

Re: Low Z noise problems

Posted: Wed Oct 13, 2010 11:04 am
by jsmcortina
kubeq_sq wrote:i have read in the mextra manual,that if i use wasted spark i can't use low z injectyors... is it true??
I'd like to check into this.

Please give a link to the page and quote the text.

James

Re: Low Z noise problems

Posted: Wed Oct 13, 2010 1:02 pm
by Peter Florance
svocapri wrote:
Peter Florance wrote:
Safir wrote:Just to be sure I'm getting this right, you're putting a small capacitor in place of the boot header on the V3 motherboard? are there any other moifications to be done first?

I have very low impedance injectors (~1.2ohm IIRC) and have voltage spikes like you describe, if this can smooth those out it would be great.
I found 47uf 35v from center leg of Q3 to center leg of Q9 works well. Negative lead to Q3.

Also running alternating instead of simultaneous.
Since I have lifted the center leg of Q9 and Q12 to run to the injector 12V feed, if I use your mod, should I connect the 47uf capacitor between Q3 and Q9 or between Q3 and the now empty hole for Q9?

Julian
good question. I'd say Q3 but I would want to try it each way