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MS3x'd VVT swapped 1995 ran fine yesterday now won't start. Logs inside.
I'm finally starting to get street miles and after a few drives I'm having issues.
Attached are two logs from last night where the car started acting odd. I noticed the WBO2 (MTXL) would, at cruising speeds, jump to full lean before returning to a normal AFR. I could feel the car react slightly to to the change, a "hiccup", if you will. The MTXL is grounded at pin 2A/2B (can't recall as I type this) with settings of: 0v - 10.9|5v - 22.39.
I parked the car last night and went to start it a little while ago to no avail. I've also attached a composite log from today. I'm trying my best to learn to navigate this **** on my own but I truly don't even know where to begin here. I switched the cam sensor with one I pulled from a junkyard car, no change.
I'm sure I'm leaving out a ton of pertinent info, I'll fill in the blanks as they come...
So it started this morning. I did nothing, changed nothing, it just started up... I tried to get a composite log but the file is 0 bytes and when I open it in TS it's blank...
I did drive the car around the block and got a log. Any input is greatly appreciated. I know it's something stupid but so am I.
I'm not the best at this stuff, but a couple thoughts.
-VVT target vs command it seems really slow to respond, looks like the gains need to be tuned. If it was me I would unplug the VVT actuator until everything runs correctly without it.
-That screenshot shows lots of sync errors, with codes 31, 32. Looking at https://www.miataturbo.net/megasquir...reasons-43775/ shows these as: 31 = Miata 99-00 - 2 cams not seen 32 = Miata 99-00 - 0 cams seen
I'm not the best at this stuff, but a couple thoughts.
-VVT target vs command it seems really slow to respond, looks like the gains need to be tuned. If it was me I would unplug the VVT actuator until everything runs correctly without it.
-That screenshot shows lots of sync errors, with codes 31, 32. Looking at https://www.miataturbo.net/megasquir...reasons-43775/ shows these as: 31 = Miata 99-00 - 2 cams not seen 32 = Miata 99-00 - 0 cams seen
I turned off VVT in TS this morning (I'll try physically unplugging actuator later) and the car wouldn't rev past 3500 or so, it's like it hit a wall regardless of speed or load. When I turned it back on I was able to rev past that "wall."
I've replaced both cam+crank sensors with junkyard units since that log, my crank sensor was gouged because of contact with the trigger wheel. Car is still behaving weird but it cranks a lot better so there's that. (I'll get new logs later)
I think your root cause is the sync loss errors. I see in the log the count starts increasing then the RPM calcs start to go crazy this is probably the "wall" you are feeling. There's some info in section 8.3.1 of https://www.diyautotune.com/download...pro_doc1.0.pdf on things to check. Maybe you need to get a sync error log (see 8.3.6 of that manual).
Thank you so much for taking the time to look at the log, I'm going to check out that link a little later.
I did another pull+log last night where it broke up pretty bad so I wanted to stick it in here, as well as a video I got of a different pull but same occurrence.
I was able to open that log, basically what it does is it logs the cam/crank pulses that occurred right before a sync error which is causing the stumbling. In the screens the green are the cam pulses and blue crank. There's 4 teeth on the crank sensor and on the cam there are 2 (but one of them is a double). So as far as I understand it the sequence should be:
4 crank pulse
single cam pulse
4 crank pulse
double cam pulse
...repeat
Sync error occurs when something happens out of sequence. The two pics below first is start of the log, second is end (right before sync error). I see there is more a gap between cam/crank pulse at start then end. They are basically right on top of each other. VVT will cause the exact timing to change somewhat but not to cause this. I'd grab a log from my car for comparison but I'm doing some work on it at the moment and wont be able to start it for a few days.
I'd check the following:
-Compare your tune ignition settings to base map for the engine if there is any difference.
-How old is the timing belt? If old or not tensioned correctly it may stretch a bit (possibly more as RPMs increase?) and I can see potentially it causing this issue. I would check it to make sure it hasn't slipped a tooth or deflects a lot.
Start of log, see still some time between cam/crank pulses
Cam/crank pulses are basically on top of each other when the sync error occurs.
I was able to open that log, basically what it does is it logs the cam/crank pulses that occurred right before a sync error which is causing the stumbling. In the screens the green are the cam pulses and blue crank. There's 4 teeth on the crank sensor and on the cam there are 2 (but one of them is a double). So as far as I understand it the sequence should be:
4 crank pulse
single cam pulse
4 crank pulse
double cam pulse
...repeat
Sync error occurs when something happens out of sequence. The two pics below first is start of the log, second is end (right before sync error). I see there is more a gap between cam/crank pulse at start then end. They are basically right on top of each other. VVT will cause the exact timing to change somewhat but not to cause this. I'd grab a log from my car for comparison but I'm doing some work on it at the moment and wont be able to start it for a few days.
I'd check the following:
-Compare your tune ignition settings to base map for the engine if there is any difference.
-How old is the timing belt? If old or not tensioned correctly it may stretch a bit (possibly more as RPMs increase?) and I can see potentially it causing this issue. I would check it to make sure it hasn't slipped a tooth or deflects a lot.
My map is a DIYAT base map for the most part, I’ve only put maybe 10 miles on the car since I got it running but I’ll get the tune/ignition settings in here as soon as I can.
The engine is a junkyard pull so the timing belt is a brand new Gates unit, I’ll attach pics of my marks after installation.
Also, I disabled VVT in TS and unplugged the actuator and I get sync errors at ~3400-3600RPM, constantly. Will not rev past that point.
Would a stock VVT engine be able to rev without VVT functioning? Like, if I had a stock ‘02 and pulled the connector off the VVT actuator would I be able to rev to 7k (for example)?
See if your noise filtering settings are hyperactive. My out of the box settings on my MS3 Basic caused the car to lose sync at WOT/over big bumps with error codes 31 and 32.
I used these and my issues were solved. Crank sensor gap is also good to check, swapping a cam sensor is cheap and easy to try as well.
See if your noise filtering settings are hyperactive. My out of the box settings on my MS3 Basic caused the car to lose sync at WOT/over big bumps with error codes 31 and 32.
I used these and my issues were solved. Crank sensor gap is also good to check, swapping a cam sensor is cheap and easy to try as well.
Appreciate the input, I’ll check those settings.
I’ve already swapped both cam and crank sensors with a couple of junkyard units (so yeah, I swapped the sensors that I’m not sure work off of my junkyard engine with different sensors that I’m not sure work off another junkyard engine...)
Your ignition input capture (rising/falling) and flip polarity are different than what I have in my VVT engine tune. My settings are Falling edge / normal. Not sure what effect that would have to change them but might be worth a try.
VVT engine will run with the VVT actuator disconnected I've done it.
12-01-2019, 04:12 PM
MS3x'd VVT swapped 1995 ran fine yesterday now won't start. Logs inside.
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