Megasquirt Ls2 coil noise???
02-23-16, 02:44 PM
#1
Ratchet_Brap
Thread Starter
Ls2 coil noise???
Anyone use ls2 coils? I am running ms3-pro using aaroncakes wiring diagram with the exception of the ls2 coil wiring, during cranking I am getting lost sync reason 11 with the occasional 17, I've heard of people wiring in capacitors but I can't find any real write ups on how to do so, the coils sit about 2 ft from the CAS and while wiring the coils I talked to Matt from DIY and he said to ground the coil grounds together (2 grounded wires per coil) (but other people say ground one to the chassis and the other ground to a sensor ground?)
We have gotten the car to start but the laptop showed rpms at 0 with the occasional spike to 3500 then falls back to 0, continues to run until it eventually just stops running (as if all spark was cut). I have posted this issue on another thread but now that I've figured out the root of all evil I am posting a thread dedicated to this issue. Any insight on this issue?
We have gotten the car to start but the laptop showed rpms at 0 with the occasional spike to 3500 then falls back to 0, continues to run until it eventually just stops running (as if all spark was cut). I have posted this issue on another thread but now that I've figured out the root of all evil I am posting a thread dedicated to this issue. Any insight on this issue?
02-25-16, 06:54 AM
#2
Full Member
Im using d514 coils in coil on plug configuration on a 13b turbo fc engine. The ECU is MS3 CPU, version 3 base board, and the 3x expander.
After a few months from first start I noticed a problem with the engine breaking down at highish revs. It turned out to be two problems.
1) There was noise on the car's power system caused by the coils firing. I used a hand held oscilloscope to diagnose the issue and fitting a 100uF capacitor close to where the coils' power wire splits 4 ways reduced the noise 10 fold.
2) I needed to adjust the VR sensor multiturn trim pots trigger level a little bit.
I've got more info with a capture of the CRO noise trace here:
AusRotary.com ? View topic - Megasquirt 3, PCB 3 and MS3X on 13BT - NOW RUNNING+VIDS!
After a few months from first start I noticed a problem with the engine breaking down at highish revs. It turned out to be two problems.
1) There was noise on the car's power system caused by the coils firing. I used a hand held oscilloscope to diagnose the issue and fitting a 100uF capacitor close to where the coils' power wire splits 4 ways reduced the noise 10 fold.
2) I needed to adjust the VR sensor multiturn trim pots trigger level a little bit.
I've got more info with a capture of the CRO noise trace here:
AusRotary.com ? View topic - Megasquirt 3, PCB 3 and MS3X on 13BT - NOW RUNNING+VIDS!
02-25-16, 08:26 AM
#3
Ratchet_Brap
Thread Starter
Thanks for the reply! How did you wire the capacitor in? (Pics would be extremely helpful!) also what capacitor was it? I am finding 100uF capacitors but the voltage ratings seem to vary. Also would you mind elaborating the VS sensor issue if you don't mind, (not sure if this applies to me due to the fact I am running the MS3-PRO)
Last edited by Scrappy_Brap; 02-25-16 at 08:29 AM.
02-25-16, 10:00 AM
#4
I ran ls2 d581 on my 20b car
6 coils direct fire
The coils were wired such that the two coil grounds on each coil were grounded together on a single bolt, at the bracket, under each coil. So each coil had 2 grounds, into one bolt, making for 6 bolts, 6 grounds.
The power wire was a 10ga wire from the fuse box, which branched off into 6 power wires to each coil clip. Then simply output wires from ecu to each coil.
There were no Capacitors used, and the coils sat ontop of the engine, very close to the CAS.
Make sure you CAS wiring is shielded!
Mine had zero issues with crank signal. And this is using the mechanical 20b (2nd gen FC) CAS.
Hope you get it figured out, and hopefully this helps to clarify that it can work.
6 coils direct fire
The coils were wired such that the two coil grounds on each coil were grounded together on a single bolt, at the bracket, under each coil. So each coil had 2 grounds, into one bolt, making for 6 bolts, 6 grounds.
The power wire was a 10ga wire from the fuse box, which branched off into 6 power wires to each coil clip. Then simply output wires from ecu to each coil.
There were no Capacitors used, and the coils sat ontop of the engine, very close to the CAS.
Make sure you CAS wiring is shielded!
Mine had zero issues with crank signal. And this is using the mechanical 20b (2nd gen FC) CAS.
Hope you get it figured out, and hopefully this helps to clarify that it can work.
02-25-16, 11:16 AM
#5
Ratchet_Brap
Thread Starter
The CAS wires are shielded (ms3pro harness has it all shielded previously) besides the 6 inches of wires from the CAS to the pig tail, (which I covered in foil just to try) what dwell are you running?
02-26-16, 06:03 AM
#7
Full Member
The capacitor was a 100v 100uF elecrolytic, which is mentioned on the page i linked. The voltage rating needs to be high enough to prevent the amplitude of the spikes from causing the cap to fail internally. I don't have pics and I'm not that keen on undoing the loom to get them sorry!
I tried installing it up at the battery but that made no difference. It was effective when placed at the ignition coil power wire, right at the coil. I think you'll find that Mazda have also worked out that a cap is necessary, there is black rectangular thing in the factory (fc) loom near the ignition coil. It is connected between the power wire and ground. I wired mine between the coil power wire (where it splits into 4) and the coil ground wire (where it splits into 4). A 100v 100uF cap is still small enough to hide in the loom, as those numbers go up the physical size of the cap also increases. My car ran perfectly fine for 6 months until I took it to a mechanic who had it over a weekend and for some reason when i got it back it was running like crap. I cant see that anything the mechanic did would upset the electrics but that is what happened.
Sync problems with Nippondenso CAS are discussed here:
https://www.diyautotune.com/support/...megasquirt-vr/
Im using the correct shielded wire for the CAS signal (purchased an extra length for the second VR separately from DIYAutotune). For about 2 years now I've had no issues with sync, Lost Sync Count is always 0 ( well..... i do get 1 if the engine is stalled, which is expected)
After a quick google it appears that you cannot adjust the VR thresholds on an MS3 pro
I tried installing it up at the battery but that made no difference. It was effective when placed at the ignition coil power wire, right at the coil. I think you'll find that Mazda have also worked out that a cap is necessary, there is black rectangular thing in the factory (fc) loom near the ignition coil. It is connected between the power wire and ground. I wired mine between the coil power wire (where it splits into 4) and the coil ground wire (where it splits into 4). A 100v 100uF cap is still small enough to hide in the loom, as those numbers go up the physical size of the cap also increases. My car ran perfectly fine for 6 months until I took it to a mechanic who had it over a weekend and for some reason when i got it back it was running like crap. I cant see that anything the mechanic did would upset the electrics but that is what happened.
Sync problems with Nippondenso CAS are discussed here:
https://www.diyautotune.com/support/...megasquirt-vr/
Im using the correct shielded wire for the CAS signal (purchased an extra length for the second VR separately from DIYAutotune). For about 2 years now I've had no issues with sync, Lost Sync Count is always 0 ( well..... i do get 1 if the engine is stalled, which is expected)
After a quick google it appears that you cannot adjust the VR thresholds on an MS3 pro
Thanks for the reply! How did you wire the capacitor in? (Pics would be extremely helpful!) also what capacitor was it? I am finding 100uF capacitors but the voltage ratings seem to vary. Also would you mind elaborating the VS sensor issue if you don't mind, (not sure if this applies to me due to the fact I am running the MS3-PRO)
Last edited by arran; 02-26-16 at 05:45 PM.
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03-01-16, 07:09 AM
#12
Ratchet_Brap
Thread Starter
Fixed the 17 code, alternator wire had some noise, now I still have code 11 but now I don't lose rpm sync while cranking, anyone know if code 11 will cause me any issues?
03-06-16, 09:50 AM
#13
Engine, Not Motor
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Code 11 is "too few teeth before 2nd trigger".
So you are losing teeth on the NE sensor.
Try tightening up the gaps on the CAS.
Make sure pots are fully counterclockwise.
So you are losing teeth on the NE sensor.
Try tightening up the gaps on the CAS.
Make sure pots are fully counterclockwise.
03-07-16, 10:05 PM
#14
Ratchet_Brap
Thread Starter
Well, back tracking some, code 17 popped up again today... And would you mind elaborating on "tightening up the caps on the CAS" and apologies for the stupid questions, I'm new to standalones, what is the "pots"
03-08-16, 11:39 AM
#19
Ratchet_Brap
Thread Starter
Cool, DIY also got back to me today and they recommended wiring in 10k resistors in the CMP wiring (composite log showed some interference) but didn't mention what wattage, I can gain access to 1/4 and 1/2 watt resistors semi-locally (30 minute drive) and plan on picking them up today, part of me thinks that either would work but at the same time with my luck I want to make sure the first time around I do it correctly
03-08-16, 09:52 PM
#21
Ratchet_Brap
Thread Starter
Well, the vr adjustment and the 10k resistor fixed the rpm signal loss issue, but didnt fix the issue of rough running and dying, what I did discover is that the rear primary injector isn't working (hooked a fuel pressure gauge up, primed the pump, and pulsed each injector) all but the rear primary injector would relieve fuel pressure, so I guess I'm picking up some more T2 injectors here in the next few days to see if all interference issues are in fact fixed (hoping I can keep the car running with a new injector long enough to see if I have any more noise issues)
03-12-16, 10:07 AM
#22
Engine, Not Motor
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Good you got the sync sorted.
The CAS needs to see a certain load on the VR sensors to help control spikes, and the resistors provide that load.
For the record in case someone else looks at the thread, 1/4W resistors are fine.
The VR circuit in the MS3-Pro is much like the Microsquirt, using a MAX9926 VR conditioner chip. It's a special purpose IC built for this use which automatically adjusts gain, rejects noise and converts to a square wave. Unlike the older zero crossing circuit, no adjustment is necessary. It's a much better design.
The CAS needs to see a certain load on the VR sensors to help control spikes, and the resistors provide that load.
For the record in case someone else looks at the thread, 1/4W resistors are fine.
The VR circuit in the MS3-Pro is much like the Microsquirt, using a MAX9926 VR conditioner chip. It's a special purpose IC built for this use which automatically adjusts gain, rejects noise and converts to a square wave. Unlike the older zero crossing circuit, no adjustment is necessary. It's a much better design.
03-12-16, 11:49 AM
#23
Ratchet_Brap
Thread Starter
Alright, so when I got the car started everything sounded fine, no real breakups besides a sputter or two (but that could be tune related) no loss of sync, but I still am getting code 11, but it doesn't appear to be messing with the rpms or running of the car? So I guess I'm wondering if maybe I should just let it slide with the 11 code or if I need to keep troubleshooting
03-13-16, 11:45 AM
#25
Ratchet_Brap
Thread Starter
It's a constant 11, I've toghtened up te caps, and the shielding hasn't been messed with (since its shielded when it comes from DIY) only things I can think of is if the shielding isn't grounded?
