Lost Sync Reason 2 and engine cuts out

All questions about MS2/Microsquirt/Microsquirt module. See also MS2/Extra manuals

Moderators: jsmcortina, muythaibxr

Post Reply
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Lost Sync Reason 2 and engine cuts out

Post by robd »

Hi All, my car is a '96 BMW E39 528 Turbo running MS2 v3 on 3.4.2 firmware. I've had an intermittent issue for a while where I get a sync loss reason of 2 and the ecu resets for a second but the car still runs. However since the weekend it's gotten worse and the engine now cuts out and wont start again for about 30 seconds to a minute! Not so inspiring when you're in the fast lane on the motorway!! Eeek!

I know reason 2 is 'missing tooth at wrong time' so it means its an issue with my crank signal. It was warmer here yesterday so I'm wondering if that could be playing a part? I did also increase my ignition advance by about 4* if this could have any effect?!

My car uses a Hall sensor so my ecu is built with the Hall\Optical circuit as per the Megamanual assembly guide. I also run a parallel install with the stock ecu so they share sensor inputs including the crank sensor. I read on one DIY autotune guide about possible issues with the Hall sensor signal if it's shared and that sometimes this can be resolved by removing the pull-up resistor from Megasquirt. Can anyone tell me if this is worth trying and which resistor I should be removing, is it R12?

Would it be worth just trying the Noise Filter settings in Tuner Studio or if I'm getting sync loss and engine cutting out is it past that?
Also would higher Dwell settings have any effect or if they were too high would they only cause issues with the BIP's and coils overheating? My current Dwell time is 2.9ms but with battery correction it generally runs at 3.1ms.

I did start having a look at the Hall sensor mod info here too but wasn't sure which option was best to try, any recommendations?

Any help would be great.
Cheers
Rob :)
grom_e30
Super MS/Extra'er
Posts: 4451
Joined: Thu Mar 08, 2012 12:44 pm
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by grom_e30 »

a tooth log of the signal will help. noise filtering prob will NOT help

and i think your reading the wrong manuals check these out: http://www.msextra.com/manuals
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????
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

Thanks , that link was just to the old manuals and one I'd saved as a favourite.

I'll try and get a tooth log today and post it up.
prof315
Super MS/Extra'er
Posts: 3760
Joined: Sun Jan 18, 2009 3:13 am
Location: Melbourne, FL

Re: Lost Sync Reason 2 and engine cuts out

Post by prof315 »

Mistake #1: Hall Opto circuit for rpm input: The VR conditioning circuits are the " standard" input of choice for everything except coil negative fuel only installs. :RTFM:

#2 :msq:
Linfert Performance/321 Motorsports
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
rickb794
Super MS/Extra'er
Posts: 6155
Joined: Sun Dec 21, 2008 10:28 am
Location: Portland OR

Re: Lost Sync Reason 2 and engine cuts out

Post by rickb794 »

I used the Optical isolator with a Hall sensor for years, and tortured it with a oval track race motor even.

The Opto circuit was modified though. And it was not used on a high count tooth wheel.

The diodes and the caps were removed and the current limiting resistor's value was changed to 1.5k.
XG1 was the signal input and 5vref was applied to optoin.
This was used with a hall sensor powered by 5vref , not sure if a 12v sensor would need changes.
Ignition capture was set to rising edge with this setup.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
prof315
Super MS/Extra'er
Posts: 3760
Joined: Sun Jan 18, 2009 3:13 am
Location: Melbourne, FL

Re: Lost Sync Reason 2 and engine cuts out

Post by prof315 »

rickb794 wrote:I used the Optical isolator with a Hall sensor for years, and tortured it with a oval track race motor even.

And it was not used on a high count tooth wheel.

And that is the issue. The Hall/Opto circuit is frequency limited and doesn't play well with high tooth count wheels.
Linfert Performance/321 Motorsports
SCCA 2019 SM National Champion Crew Chief
SCCA 2023 FP National Champion Tuner/electrical engineer
100s of MS systems built installed and tuned
Support the developers!
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

Thanks for the replies everyone, sorry for my slow reply, I've been away for work.

I was driving the car again the other night on a long journey and this time it lost sync 13 times, 8 of which resulted in the car cutting out. The issue only seems to have gotten worse where the car cuts out, since I upgraded the firmware to 3.4.2 from an older pre3.3alpha firmware and I'd added 4* timing. I tried lowering my dwell settings and taking that 4* timing back away just to test and that made no difference!

I've attached a log from the other day where it was losing sync. By this time it had already happened numerous times but I managed to plug my laptop in and capture it.
I did try doing a tooth log the other day too, but with the tooth logger running the car seemed like it went to running on 4 or 5 cylinders after a few mins and I had to power down the ecu and start again. This was while logging at the same time and the issue went away as soon as I stopped the tooth log and started the car again. I've attached that tooth log as well.

Can anyone tell me if there's any other changes I'd need to do if swapping from the hall circuit to VR other than what's in the manual?

Thanks very much.
Rob :)

Edit: the log file is too big so I've attached a graph screenshot instead. In this instance the sync loss reason didn't show up until further along the log but you can see I was driving at a steady state before it just drops to 0rpm and then it shows a sync loss count. If anything else would be helpful please let me know.

My thoughts at the moment are I'm going to review my grounds and look at the VR circuit and perhaps try the latest beta firmware. Ideally I would prefer to try one thing at a time to rule it out, but the issue is its only doing it on long motorway journeys and obviously that's not ideal for testing losing all power in traffic!
hybrid
Super MS/Extra'er
Posts: 1275
Joined: Thu Apr 07, 2005 11:23 pm
Location: Sydney, Australia
Contact:

Re: Lost Sync Reason 2 and engine cuts out

Post by hybrid »

I have used the Opto circuit on a 32-1 wheel with no issues on a V8 to 6500 RPM.
Do not load someone elses tune and expect it to work for you!
Image
rickb794
Super MS/Extra'er
Posts: 6155
Joined: Sun Dec 21, 2008 10:28 am
Location: Portland OR

Re: Lost Sync Reason 2 and engine cuts out

Post by rickb794 »

I think a Bimmer has 60 tooth wheel, no bueno.
Correctly identify your MS ecu here
Read the Do's and Don'ts to avoid the common pitfalls before starting your install or asking for help
Use only these manuals other manuals may cause brain damage or worse.
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

Yeah it's a 60-2 wheel!
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

I tried the latest beta firmware and I still get the same issue!

One thought I just had, my ignition input capture is set to Falling Edge, but I noticed on the tooltip it says you can get timing drift and sync loss if the ignition capture is wrong. Looking at my tooth log I do have one very tall line compared to all the other short lines, so I assume this means I have it the right way?

I'm happy to swap over to the VR circuit if that's the preferred option, but can anyone advise me on any mods I'd need to make for it to work with the Hall sensor?

Also if it helps, I did another long run in the car on Monday, car was fine on a 2.5hr long run first thing in the morning, then in the afternoon coming home, when it was hotter and ambient temps were around 20c, the car cut out about 8 times on the drive home! So would this just point to the opto-isolator getting hot maybe?

Also if your Dwell settings are set a bit too high, if the BIP373's shut down, would that result in a similar scenario? I was just wondering if maybe my dwell settings were on the edge and then the addition of hotter ambient temps and a longer journey is pushing the BIP's over the edge so they're shutting down?!

Any more thoughts or advice would be great.
Cheers :)
grom_e30
Super MS/Extra'er
Posts: 4451
Joined: Thu Mar 08, 2012 12:44 pm
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by grom_e30 »

id be tempted to try the vr input its now the recommended input for hall and vr sensors, instructions can be found here: http://www.msextra.com/doc/pdf/html/MS2 ... e-3.4.html

the opto was designed to trigger off the coil so maybe 4 times per engine rev (for a v8 engine) and you are making it work like 58 per rev.
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????
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

Thanks very much, one more question, to check my Hall sensor type, whether it has an internal pull-up already or not, can I just measure the voltage on the signal wire to see if it's 0-5V or 0-12V or is there a recommended way to check?

Thanks again.
grom_e30
Super MS/Extra'er
Posts: 4451
Joined: Thu Mar 08, 2012 12:44 pm
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by grom_e30 »

yeah connect the sensor power and ground, without a bit of metal in front of the sensor measure the voltage on the signal wire if its 5v or 12v you don't need the pull up.
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????
hybrid
Super MS/Extra'er
Posts: 1275
Joined: Thu Apr 07, 2005 11:23 pm
Location: Sydney, Australia
Contact:

Re: Lost Sync Reason 2 and engine cuts out

Post by hybrid »

How many RPM are we talking when it resets?
The opto was able to handle over 3,300 teeth per second on my car.

It's probably best to change to VR if you can - if for no other reason than it stops the comments that Opto doesn't work properly.
Do not load someone elses tune and expect it to work for you!
Image
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

grom_e30 wrote:yeah connect the sensor power and ground, without a bit of metal in front of the sensor measure the voltage on the signal wire if its 5v or 12v you don't need the pull up.
Thanks very much, Ok I'll try that and then put together the VR circuit to try.

hybrid wrote:How many RPM are we talking when it resets?
The opto was able to handle over 3,300 teeth per second on my car.

It's probably best to change to VR if you can - if for no other reason than it stops the comments that Opto doesn't work properly.
It can be different every time, but seems most noticeable at lower rpm's which is generally motorway driving, but I have had it when accelerating hard up higher rpm's!

The main thing that bugs me is how it has worked for a while now other than the odd stumble/sync loss but the car wouldn't cut out like it does now! The car's been boosted and on MS for almost a year now and covered nearly 10,000 mls. This is why I was wondering if it was an issue elsewhere. I have ordered a new crank sensor as well just in case it's that!
robd
Experienced MS/Extra'er
Posts: 331
Joined: Wed Feb 29, 2012 6:14 am
Location: UK

Re: Lost Sync Reason 2 and engine cuts out

Post by robd »

Hi All, I just wanted to update to say I had a successful motorway trip on Friday, about 2.5hrs each way and without an issue. The only thing I'd changed was fitted a new crank sensor. I did't get any lost sync errors while driving and no cut outs. Fingers crossed that's a sign of things to come and it was just the crank sensor.

I'll update if it happens again, but if not just wanted to share in case it helped someone else in the future.

Thanks for the help everyone. :)
Post Reply