What would cause SecL to reset?

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jsdevel
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What would cause SecL to reset?

Post by jsdevel »

I've been troubleshooting my car lately with MrgaLogViewer and I've noticed that when my engine dies SecL resets to 0. What would cause this and why does it reset?
billr
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Re: What would cause SecL to reset?

Post by billr »

The 12V input power to MS has dropped too low (under about 7V) and the MS has re-booted; restarted its clock.
slow_hemi6
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Re: What would cause SecL to reset?

Post by slow_hemi6 »

Or maybe the 5v from the reg has fallen over.
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Cheers Luke
jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

slow_hemi6 wrote:Or maybe the 5v from the reg has fallen over.
Would the logic level outputs for LS2 coils cause this to happen?
slow_hemi6
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Re: What would cause SecL to reset?

Post by slow_hemi6 »

If you followed the manual then that's generally not likely to happen. Plenty of people running 8 ls coils out there. Added any other stuff that runs of the 5v? You should be able to see with a voltmeter if it is the 12v to the MS that is dropping out and then if it is not the 12v dropping out you should be able to see if it is the 5v by putting the meter on the 5Vref to the tps and checking that.
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grom_e30
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Re: What would cause SecL to reset?

Post by grom_e30 »

could it be the low-z injectors?
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

I currently have a fuel pressure sensor and a Jbperf P&H driver board for Low-z injectors connected to the 5v supply from the 3.57 board. Could that be the issue?
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Re: What would cause SecL to reset?

Post by racingmini_mtl »

jsdevel wrote:I currently have a fuel pressure sensor and a Jbperf P&H driver board for Low-z injectors connected to the 5v supply from the 3.57 board. Could that be the issue?
If both are functioning normally, they won't be an issue for the 5V power supply on the 3.57 board.

Jean
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jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

racingmini_mtl wrote:
jsdevel wrote:I currently have a fuel pressure sensor and a Jbperf P&H driver board for Low-z injectors connected to the 5v supply from the 3.57 board. Could that be the issue?
If both are functioning normally, they won't be an issue for the 5V power supply on the 3.57 board.

Jean
Thanks Jean! Yea, the car runs great, but then suddenly dies exactly when SecL resets to 0.

In the spirit of :RTFM:, I've just noticed that there's a Setting Up companion manual to the hardware guide (the one I've been following). The relevant section is under troubleshooting:
Check where the Megasquirt-2 is getting power from a clean source - ideally, you’ll want it to be powered off
the battery, with no devices that draw significant current getting power from the same feed. Many resets
come not from EMI / RFI interference, but from something like an ignition coil, fuel pump or wideband
controller injecting voltage spikes into the power feed.
I thought I could get away with the factory power feed that came through the firewall from the battery, but I'm wondering if I should run something a bit thicker.

Here's what's currently being powered off of the factory power feed:
  • ECU
  • DSM CAS
  • Innovative WB
  • 4 LS2 Coils
  • 4 Low-z Injectors
  • 2-wire PWM IAC valve
  • Main relay
  • Fuel Pump Relay
  • Fuel Pump
Seems like I'm suffering from voltage spikes.

If I ran 8 gauge wire from the battery and fed the following would I see an improvement?
  • ECU
  • DSM CAS
slow_hemi6
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Re: What would cause SecL to reset?

Post by slow_hemi6 »

The wire does not have to be huge, MS only needs a 2 or 3A fuse, It just needs to be clean. So not sharing with a lot of other noisy equipment. Keep in mind the feed wire also needs to be ignition switched so you may need a relay so your clean and fused feed from the battery, is also switched on and off by the ignition key.
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jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

I ran a 16 gauge AL wire to the battery. On my sound scope it looks like there is steady noise, albeit minor. Still getting resets. How steady does the signal need to be before a reset is triggered?
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Re: What would cause SecL to reset?

Post by prof315 »

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jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

MSQ attached. You can see that I cranked the engine and it started / idled fine for roughly 20-28 seconds, then a reset occurred. This is with a clean power source (only sharing with the DSM CAS).
jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

Is it possible for LS2 coils and or low z injectors to backfeed and stop current flow coming from the MS ground? I currently have my ECU sharing a ground point with everything else (LS2 coils, low z injectors etc.).
jsdevel
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Re: What would cause SecL to reset?

Post by jsdevel »

UPDATE: I Isolated my case from the chassis ground and saw a HUGE difference. I also fastened the DB 37 and DB 15 connectors as well as upgraded to a new shielded serial to USB cable from EFI. All this combined resulted in SecL almost dissapearing entirely.

My next step is to have a dedicated power and ground all the way back to the batter for the ECU and the LC2 wideband controller.
DaveEFI
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Re: What would cause SecL to reset?

Post by DaveEFI »

Not generally a good idea to use the factory power feed. Best to run in a fresh one direct from the battery, with suitable relays switching that. Unless the factory one is already that, and of a suitable gauge.
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