NA VVT Engine, MS3 Basic, 1.4.0 Firmware

To regain power I pull over and car automatically regains sync after roughly 30 seconds, sometimes earlier.
The check engine light and battery light on dash light up until sync is regained.

Composite log and datalog captured and attached. Issue occurs @ 700 seconds on datalog and ~675 seconds on composite log. Will upload a cut-down log once I figure out how to crop the composite log.
I have had this issue since I installed the megasquirt almost a year ago, this is the only remaining issue that I can’t figure out
I have a 5x racing timing adjustment wheel instead of the stock one from my time running the OEM ECU, it has a slight offset when compared to the OEM timing plate and if replacing the crankshaft position sensor doesn’t fix this, swapping to the OEM plate will be my next move, although I suspect it is either the sensor or potentially dashpot related (?)
Doesn’t occur every time when shifting at redline, can be a few days before it occurs, sometimes it can occur multiple times in a day. Occurred when cold/warm outside.

Things I have tried

• Checking crankshaft sensor gap - Credit card length between the crank sensor & crankshaft plates 4 nubs - Within 0.5mm- 1.5mm spec
• Replacing camshaft position sensor - Same issue remains
• Adjusted noise filtering settings
• Checked grounds for MS & Wideband

I have ordered a second camshaft position sensor to try, as well as a replacement crankshaft position sensor as I haven’t replaced the current one ever.
If I shift before 7k RPM my car never loses sync.

Any ideas?


Red arrow @ Sync loss in main .msl file

 

Adjust the R52/R53(?) Trimpots.

 

I will look into removing the MS3 Basic & adjusting the trimpots forward a little, thanks for the suggestion

 

Apparently the MS3 Basic doesn't have physical trim pots and uses opto-isolators (?) to isolate electrical noise instead, so there isn't any adjust-ability there.

I will continue with replacing the crankshaft position sensor/cam position sensor and will try re-gapping the sensor before reaching out to Reverant about this. Also on the table is disabling the noise filter entirely, as apparently it isn't even needed for the car to run.

 

I turned off the noise filter and drove the car around for about an hour with no sync loss, it also seemed to run a bit smoother when warming up.

 

After replacing the camshaft position sensor and crankshaft position sensor, the issue shifted from losing sync near redline to losing sync when cruising at 3k-4k RPM. I changed my cruise timing back from 34 degrees suspecting it could be misfiring, however the issue still remains. I will be swapping the OEM timing plate back in and moving the crankshaft position sensor as close as possible to the plate to see if that resolves it. I can't see a sync loss logged in the composite logger lining up with code 31/32 in the actual catalog. I suspect the slight offset in the OEM timing plate and the different plate material to the 5x racing timing wheel may be causing the MS to miss a crankshaft rotation tab.

If I turn on the noise filter instead of a slight hiccup and CEL the car loses throttle and any control over the engine for a good 7 seconds, so I turned the noise filtering settings back off as it seems to do more harm than good.

 

Your issue is with the crank signal, not the cam signal. Put the previous cam sensor back in, as we don't know at this point if the new issue is caused by the cam sensor.

Please attach the composite log shown in the first post as well as a current composite log.

 

Attached my current tune, a datalog, and a composite log of this issue occuring. Sync loss 32 is logged on this one, can't figure out how to trim .csv files.

Switching the old cam sensor back in to see what happens

 

The composite log is 1708 pages long, I'm not going to go through all of these to find it. Where is it?

 

That's the weird part, there doesn't seem to be a single instance of sync loss logged in the composite log, I went through it and the cam/crank pulses seem perfect all the way through the log as well, while the datalog reports a sync loss w/ code 32 about 1/3rd of the way through the log.

The 2 other composite logs and datalogs I have recently taken also have the same thing, either code 31 or 32 logged, nothing out of the ordinary on composite logger. Could be misfiring? Will see if I can recreate this with the original cam sensor.

I have a stretch of road that usually reproduces the issue, I will try that and see if a small composite log shows anything.

 

In my previous post, I asked you to upload the original composite log, the one which you showed in the pic in the first log, and if it's more then 30-40 pages, please tell me where the sync loss happens.

 

Ignore, I am an idiot and the missing sync is showing once I match the time on the msl with the time on the csv. Incorrectly assumed going to the center of the .msl and the center of the .csv was the same place in the log, when I should be going off of the time/toothtimes logged on the left side of the composite logger reader.

While the datalog always reports sync loss with either Code 31 or 32, the composite log never shows any missing sync. It always has 1 cam pulse for every 4 crank pulses.

I took the car out and managed to get 4 composite logs & regular datalogs of the issue in about 30 minutes, datalog 3 is the shortest as it took me about 60 seconds to get a second temporary sync loss and pull over to restart logging. None of the composite logs are suspect, while the datalog reports code 31 or 32 every time, the composite log looks like everything is completely fine. The issue starts around 3.5k RPM every time, A/C is always on due to FL weather at the moment. The sync loss issue seems to be getting worse for some reason.

Now running the original crank sensor, new cam sensor w/ 1.5 credit cards worth of gap, and the same 5x racing timing wheel which I originally advanced to 14 degrees when on the stock computer. I believe this would make the crank pulses show earlier than normal with an OEM timing wheel, if I set the original timing offset in MS is having this wheel still installed an issue? Is MS picky on the tab time between crank/cam pulses & its throwing a fit about it? I am going to be installing the OEM wheel when I get the chance to, as the crank log shows nothing and its just about the only thing I haven't tried yet.

Running the same tune I most recently attached.

EDIT - Found this post with a crank log, going to try at least turning the timing plate back to match the OEM one and re-timing the offset on the MS to see if I can get the cam signal further from the crank signal. Easier than pulling both belts off, if this doesn't do it I will be trying that out as well.

 

Changed the noise filter settings back to what the basemap had set, re-enabled the noise filter. Haven't tried the old settings with the new crank sensor.

 

Let's give this one more try.

 

D'oh

I apologize for misreading your statement entirely.

Uploaded the .csv file from 4/23 also recorded at the original time of the original .msl, I went through and the sync loss should be shown in this screenshot, sync loss at 716 seconds in the msl, 673 seconds on the composite log.

Also I am realizing I have been reading all composite logs incorrectly and the sync loss does show up and match with the .msl. What I thought were sync losses at startup are actually the first times the car loses sync, which is where the representation of the cam/crank seems to start.

 

Any updates on this? I am having a similar problem.

 

Which issue are you having, the sync loss when crusing at a certain RPM or the sync loss when reaching redline? For both I would adjust trim pots (if you have them, MS3 Basic & Mini don't have physical trim pots) and check crank sensor gap/replace the crank sensor if you haven't already. Capturing the issue in a composite log is key to fixing these.

I have had the sync loss at cruise issue happen once in the last 2 weeks and I fudged the crank/cam sensor log somehow so it didn't show up there, so I have nothing to go off of until it happens again and I capture it on a log.

Changing the noise filtering settings back to the basemap helped almost eliminate the issue entirely, once I capture the issue on the log I am somewhat confident I can figure out what to look for. I suspect the timing plate is causing it all, and will be swapping the oem one back on and recalibrating my timing offset and seeing if that changes when I have the chance to do so.

Basemap settings

 

I have no intention of thread jacking and am just trying to supplement with a scenario that appears to be related to what you are encountering. If the mods choose to move this I suggest into my build thread.

For starters: Thanks for the prompt response!

I have encountered the sync loss when driving and the car has gotten up to temperature. I have attached a data-log that I believe I captured after I had to pull over with my friend I was showing the car to for the first time! (embarrassing!) So during cranking and after that you can see I was having a sync loss. I did not have a composite log being taken with this setup. I swapped in two different cam sensors that worked 1 new and 1 used and the car wouldn't even come on. The car was towed home.

Yesterday, after doing hours of research and compiling all of the sync loss threads on here, I turned the car on for the first time since that incident (6 months ago - I have a son that is 5 months so you can see why I haven't gotten back into this until now). I managed to charge up the battery and like a charm she came on with no sputter or issues. I took some composite logs after swapping around my Ignition Input Capture setting from Falling Edge to Rising Edge. Falling Edge worked, but Rising didn't(car has been running with falling edge for at least a year and a half). I need to look through emails, but I may have ran this ECU on my 1.6L car. This makes me wonder if I DO in fact need to adjust the VR Pots. My concern is that I will end up how pdexta did and then the car won't start at all.

My to do list compiled from several of the forums posts are the following:

1. I verified my noise filter was off yesterday so I can turn that back on and see what happens like you are suggesting.
2. Check gap on crank sensor and adjust per OEM specs- note I did this last year and didn't make a difference that I could tell.
3. Purchase and install new crank sensor for the heck of it - ordered since they are cheap
4. Check base timing and make sure it is right - I have done this also last year and will check again just to be sure.
5. Clean up engine grounds again and re-secure. Also will check the PPF ground is attached snuggly.
6. Attempt to document location of VR Pots and then proceed to adjust them.
7. Since I don't have a garage at the moment I have lowered this on the list- I will check the OEM trigger wheel and make sure it is in the right place.
8. If it is in the right place I might get the 36-2 FM trigger wheel since it is not very expensive - For Science!
9. Consider running additional grounds as needed.
10. I might disconnect the aftermarket amp from my car to ensure there is no additional noise being added to car. I have a weird feeling it is adding some noise to the system.

The issue with troubleshooting all of this is I need to get a proper license plate and insurance on the car now to go for drives...lol

Additional details: I have a Brain built MS3x and a built BP4W Engine.
Attachments:
2020-08-30_09.20.29.msq - This is my Current Tune
2020-02-23_13.43.14.msl - Data Log from February where the Loss of Sync was happening - no composite log available.
HOT START.msl - Data Log from yesterday showing that I did not have any loss of sync - note I was not driving car around just letting it idle
hood closed gettin hot.csv - composite log that goes with data log HOT START
2020-08-29_15.27.18.csv - composite file when I was trying to get car to turn over after sitting for a while yesterday. It's like it couldn't see my crank sensor. Not sure if that should be happening when it has been sitting for a while or not.

I think together we can resolve both of our issues!

 

The issue always occurs around 3100-3600 RPM when at a stable TPS position.

I managed to get the issue to happen twice today, once per ~30 minute drive. The first log, issue occurs at 471 seconds. Two weird things happened, the RPM recorded directly before the sync loss shows 5500 RPM for a single second, instead of the 3200 RPM recorded miliseconds before. Additionally, after the sync loss my VVT stopped functioning entirely until I turned the car off & on again. The VVT Angle 1 reading remains at 30 degrees the remainder of the log, VVT Duty % is at 0% the entire remainder of the log, and the cars power falling confirmed that VVT stopped functioning. Unfortunately, the crank log doesn't show the sync loss anywhere, need to see if there is a setting for that, logs showing crank/cam signal pulses only seem to start when sync loss occurs.

Second log, the issue occurs at 347 seconds. Crank log seems to show two missing crank pulses and also shows red sync loss indicators, screenshot below. VVT remained functional the entire time after, no junk RPM reading in the log immediately before the sync loss.

I am going to try replacing the crankshaft plate this weekend and re-timing the engine, oil level is fine according to the dipstick, no idea why VVT dropped out entirely after a sync loss, don't believe that has happened before. Added a quarter of a quart just in case.

 

Have you adjusted the VR Pots yet?