12v noise

All Megasquirt 1 support questions. See also the Documentation

Moderators: jsmcortina, muythaibxr

Post Reply
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

12v noise

Post by Suprazz »

I'm having big issue with noise on the 12v of the car.

I installed a ms1extra last year. Everything was working fine. Then this winter, the owner of the car rebuilted the engine.
Engine: 2jz-gte
running ms1 with low impedance injectors with a resistor pack
3x MSD twin towers coil pack drive by original igniter.

After the rebuild, the guy was having troubles with hard cuts on with the ms. There is so much noise that the ecu reset everytime he hit boost and fews times at idle...
I double checked all grounds and everything is like before. I'm already using a capacitor on the igniter.

I can add a capacitor to the MS but this wont solve my problem... I will try to add a capacitor near the twin towers coils pack.

But I still dont understand why is was running well last year.

This is what it look like at 1000 rpm. Noise increase with rpm
Image
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: 12v noise

Post by Matt Cramer »

Where is the MS getting power and ground?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

From b+ (factory ecu 12v) and a good body ground.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: 12v noise

Post by Matt Cramer »

Suprazz wrote:From b+ (factory ecu 12v) and a good body ground.
In my experience, there's rarely such a thing as a good body ground. I recommend grounding the MS to the engine block or cylinder head. There's a reason most OEM wiring harnesses do this.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

ok I'll try this.

BTW this is what it look like when I hit boost. I add a 220uF capacitor to the ms so it help a little bit for the noise at idle. You can see while rpm are growing, noise increase and at ~10 psi I always have a big glich and the ecu reset and I'm also loosing the communication with TS.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

little update.

You were right, a good engine ground is a WAY better than a body ground.

But I still have my problem.

This time, I kept the pedal to the floor and it keeps resetting.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: 12v noise

Post by Matt Cramer »

Can you post a data log of the resets?
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

yes but almost every time I'm loosing communication after the first "cut"...
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Matt Cramer
Super MS/Extra'er
Posts: 17499
Joined: Thu Apr 16, 2009 8:08 pm

Re: 12v noise

Post by Matt Cramer »

Try soldering a 0.1 uF capacitor across the boot header.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

I added a 0.22uF between pin 2 and 6 of the CPU and also between pin 1 and 2.

I also added a 1nF to the bootloader jumper.

And a 220uF on the 12v input of the megasquirt
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
jsmcortina
Site Admin
Posts: 39585
Joined: Mon May 03, 2004 1:34 am
Location: Birmingham, UK
Contact:

Re: 12v noise

Post by jsmcortina »

Suprazz wrote:I also added a 1nF to the bootloader jumper.
Why so small?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
elaw
Super MS/Extra'er
Posts: 2926
Joined: Fri Oct 16, 2009 6:20 am
Location: Wilmington, MA

Re: 12v noise

Post by elaw »

Is your fuel pump powered from the same line that feeds the Megasquirt?

I fought with similar issues for a long time and finally set up the fuel pump to draw power from another circuit and the problems vanished.
Eric Law
1990 Audi 80 quattro with AAN turbo engine: happily running on MS3+MS3X
2012 Audi A4 quattro, desperately in need of tweaking

Be alert! America needs more lerts.
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

Ok, I'll try bigger on the bootloader jumper.

Yes the fuel pump is on another circuit.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

I made other tests, It changed nothing. I added a bigger capacitor on the bootloader jumper.

I dont know why but yestesday, the car was running a way too rich. The day before yesterday, idle was a 14,7. Yesterday, I after the warmup, i was running less than 11 a idle and idling was hard.

And Same problem, I have an other datalog.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
jsmcortina
Site Admin
Posts: 39585
Joined: Mon May 03, 2004 1:34 am
Location: Birmingham, UK
Contact:

Re: 12v noise

Post by jsmcortina »

Lets get back to basics here.
Nothing changed with the Megasquirt over the winter but now the car is running badly ?
Don't look at the Megasquirt! Look at what else changed on the car.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
Kmsgli
Helpful MS/Extra'er
Posts: 134
Joined: Wed Feb 03, 2010 8:39 am

Re: 12v noise

Post by Kmsgli »

I had a simmilar issue with my VR6 turbo when i first got it running and i have a noisy 12v Batt signal and I chased my tail for months only to find out I carelessly put factory Spark plugs in the car and under boost they where detonating as they run hot (platnum +4's). Im not saying that is your issue but the wrong spark plugs in a car that boosts more then it should will give you a nasty bucking hesitation during boost but drive regular while cruising.

Its worth looking at your plugs before you start ripping your MS apart like i did. May be wrong but its easy enough to try.
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

good to know.

I noticed yesterday that the car is running with ngk g-power spark plug and normally I use ngk copper type or v-power but I didn't try to change the sparkplugs.

Now car is running a way better (I moved few other grounds but I'm still don't understand what's happening). I can make pulls and run the car run great but the ms reset is still happening under boost.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

Ok,

I changed the megasquirt for an other one of a friend.

Car is running a way to rich with the exact same progarmmation.

The megasquirt of my fried don't reset but I'm always loosing communication with tunerstudio 1.50
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Peter Florance
Super MS/Extra'er
Posts: 3653
Joined: Fri Apr 02, 2004 8:40 pm
Location: Virginia Beach, VA
Contact:

Re: 12v noise

Post by Peter Florance »

MegaSquirt installations should pass this test:

if you unplug MS box and measure resistance from any sensor's (MAT, CLT, TPS) ground to car/engine ground , you should not have continuity.
Peter Florance
PF Tuning
81 BMW Euro 528i ESP Car
60-2 Wheel LS2 Coils, Low Z Inj
Co-Driver 1999 BMW E46 DSP car.
Suprazz
Master MS/Extra'er
Posts: 499
Joined: Mon Jan 22, 2007 7:58 pm
Contact:

Re: 12v noise

Post by Suprazz »

Thank you. This solve my problem. I realised that the MAT and TPS were grounded on the intake manifold.

Now everything work a way better.

Btw with all this problems, I realised that the maximum and minimum baro correction limits don't seems to work on 029y4 because when the ms reset, baro was at ~140 kPa and my maximum was set a 105.
Best looking and most advanced CAN-bus gauge
Toyota Supra 7MGE, 7M-GTE and 1JZ-GTE Plug and play ECUs: http://www.perfecttuning.net
Serial to Bluetooth or Serial to WiFi
DIYAutotune Canadian, EFI Source and ECUMaster reseller!
Post Reply