Data Drop after sync loss?

nathanhardy · Post by **nathanhardy** » Sat Aug 30, 2014 10:35 pm

so the car at higher rpm every once in a while has a snyc loss I loss rpm on the dash for a brief sec then the car comes back to life and runs fine, it has been doing it as I am veal tuning not related but after it happens if I hit burn its pops up and says cant burn some thing some thing data dump? could some one lead me down the right path and maybe explain.. i'll try for a data log and msq but im sure someone can chime in before! thanks.

LT401Vette · Post by **LT401Vette** » Sun Aug 31, 2014 5:34 am

Sync loss as in the MegaSquirt loosing sync with the toothed wheel, or are you having a comms drop out?

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 8:30 am

Maybe both?? I wish I could if taken a screen shot but from what I remember it say after it it seemed to sync loss and I click burn was full data dump something 5 I think.. And it wouldn't burn to ms after till I power cylcled

LT401Vette · Post by **LT401Vette** » Sun Aug 31, 2014 9:23 am

Do you have a data log?

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 10:30 am

Hey Phil I sent you an email because am away from my laptop but it has the log in it!

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 10:35 am

Is there any documentation on error codes and what they mean?

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 2:26 pm

1137 in the log

Post by **jsmcortina** » Sun Aug 31, 2014 2:34 pm

nathanhardy wrote:Is there any documentation on error codes and what they mean?

What kind of error codes?

James

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 2:45 pm

jsmcortina wrote:
nathanhardy wrote:Is there any documentation on error codes and what they mean?
What kind of error codes?

James

Ill try for a screen shot when it happens, but ts type warnings

how would I set a filter to limit mat temps before 100 and greater then 110? I tried one I found and it didn't like it

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 7:10 pm

heres a picture

LT401Vette · Post by **LT401Vette** » Sun Aug 31, 2014 7:13 pm

Looking at the log sent, it looks like the real sync, Lost Sync Reason = 2

But the errors you are getting from VEAL are from a crc failure, not your sync loss.

LT401Vette · Post by **LT401Vette** » Sun Aug 31, 2014 7:19 pm

Yep, looking at your logs a bit more. When the sync loss it happening, SecL is going to 0. So it looks like your MCU is suffering from a reset. So all the change that TS had sent to the MegaSquirt, but not burned are lost and the next time TS checks the data will not match causing a CRC error.

You need to fix the reset.
There may be some heavy noise from the ignition.

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 7:31 pm

LT401Vette wrote:Looking at the log sent, it looks like the real sync, Lost Sync Reason = 2

But the errors you are getting from VEAL are from a crc failure, not your sync loss.

crc failure? would using rpm lags help? with the sync loss. the sync loss is vr sensor rpm related

LT401Vette · Post by **LT401Vette** » Sun Aug 31, 2014 7:35 pm

No, the resets are most likely at the hardware level. There is too much noise or fly back causing the MCU to reset, essentially reboot. That is why everything in RAM is lost. It reloads from FLASH after the reboot.

It would likely be the ignition wiring, but possibly the injectors.

nathanhardy · Post by **nathanhardy** » Sun Aug 31, 2014 8:58 pm

I feel as if my wiring is set up correct everything is shielded with very high grade wiring to over kill status. my spark plug wires do come close to the injector harness maybe with in a inch, other then that everything is neat and laid out correctly! when you say mcu do you mean ecu or some in side the ecu?

LT401Vette · Post by **LT401Vette** » Mon Sep 01, 2014 6:45 am

Yes the MCU is the processor in your MegaSquirt.

There are quite a few possible causes for resets, if voltage is holding steady, they typically always relate to noise getting back to MCU.

What kind of coils are you running? Do you have any capacitance fitted to the positive lead of the coil(s)?

nathanhardy · Post by **nathanhardy** » Mon Sep 01, 2014 8:20 am

MSD gm twin towers running direct fire from the ECU. I'm running a cap to a stereo and have notice when I shut the key off the tach raises and the car takes a sec to stop running as do my dash indicators they dim to nothing.. where is the best place to look on a data log for noise? or in general how do you test for it if you can see it in logs? I am going to remove the stereo cap and check the vr sensor some times it get metal on it, it is a new motor and see if I can't figure out why it run for a sec after key off because it never did that before I rebuild the wiring with better shield wire and motor but everything was routed the same so no major changes. I also just notice my head gasket is leak coolant into the cylinder at high revs could that cause the motor to jam up, it just started smoking white on the last drive so I doubt it but when this happens the car does lurch me forward in the seat

nathanhardy · Post by **nathanhardy** » Tue Sep 02, 2014 11:15 pm

nathanhardy · Post by **nathanhardy** » Fri Sep 05, 2014 9:35 pm

So out of chance it did it a bunch more as I was running it in my drive much more under load like letting the clutch out. Then noticed it one as I revved it by the throttle body turns out my spark plug wire had a cut in the insulation taped it up and so far so good! Can someone explain the logic behind why it would cause a sync loss like that? So I can learn from it!

grom_e30 · Post by **grom_e30** » Sat Sep 06, 2014 1:37 am

the ht voltage from the plug wires could be making its way back to the ecu.

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Data Drop after sync loss?

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