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I'm at VIR. I was coming down the hill from the false grid to get on track for my first session of the morning, and the car lost power for a split second. The attached log shows the engine went into Overrun at 1234.766 seconds. WTFuck would make it do that? No loss of sync. I didn't go out for my session.
I was in a hurry when I posted. The car acted like it completely lost electrical power for a split second, otherwise, I never would have noticed. I went back through the log and figured out where I was when it happened, and the only thing that seemed out of place was the Overrun. Are my ORFC settings okay?
Looks normal to me. You have it set so you have to be in overrun for 2.3 seconds before it cuts fuel, no where in that log were you in over run for over 2.3 seconds.
Check mechanical things, are your battery terminals loose? Is the battery sliding around and shorting out? Ground straps loose?
Battery connections are tight, and the battery, an ETX-14, is secure. i checked the voltage with the engine running, 13.71. Afterwards with the engine off, 12.70.
Attached is a log from a track session I just did. I was preparing to downshift going into Turn 11, and the battery light came on. It may be failing, but I will also check the belt since it was removed for the timing belt install. I called it done after seeing the battery light.
If you scroll about halfway through the log, there are quite a few yellow bars that appear to be a "Launch - Generated Timeslip", and accompanying times and distances for a 1/4 Mile run. I never touched the tablet I use to collect the log file using Shadow Dash. The car seems full of gremlins today.
Thanks much,
The ground strap at the back of the engine by the dipstick, which I had removed to do the transmission swap, is secure, and the alternator belt is tight.
I've missed stuff before, but I don't see any sensors dropping out or other reasons to fault tune. If this were me, I'd be looking for a physical issue with anything you touched with the timing belt swap, and/or update the firmware to eliminate any corruption with that.
It was an idea, because nothing else seems to be wrong in the log that I can see, but if you're saying it's tightly connected and not moving, then no, probably not, sorry if you've been spending the last 2 hours looking for battery issues...
In the last log you posted, you did go into 104% WUE briefly at 312 seconds, which tapered off within 3 seconds. Which is strange because in the tune you posted in the original post has WUE flat lined at 100%.
I think I did find what you were referring to as power loss in the first log, happens a few seconds later than you mentioned, more like 1327. Is your crank sensor too far from the trigger wheel? I know I have issues with 36-2 trigger wheels when the sensor is at factory spec, I set it closer to .015-.020", rather than the factory spec of .020-.060".
Here's a short log of just blipping the throttle and driving around the paddock. Could it be fuel?
I'm going to narrow the gap on the crank sensor. The VIR key card is thicker than a normal credit card. Not sure if I have a crank sensor in the box of stuff.
I readjusted the crank sensor and took a log of just blipping the throttle parked. That's the one with the earliest time. No apparent change. Then I loaded a restore point tune (attached) and did the same throttle blipping. The rpm drop was noticeably less. I was messing with the tune as it was very rich at idle.
I had also reset the base timing as I chronicled in another thread, and I did that before I realized I had not completely seated the TPS connector.
I called it a day. Something is telling me not to go out on track.
The car was running great before the timing belt change, then it was running like ****. Soooooooooooooo, for whatever reason, I decided to check the base timing. It was off. I changed it from 5.9 to 8, and the car was running (idling) beautifully. The next day, when I took it for a ride, it was running like **** again. Also, it had a hard, long start, with some bucking, so I pulled some more timing from the idle area. Then I figured out I hadn't completely seated the TPS connector. The restore point tune is not affected by the change to the base timing, and the rpm drop Curly mentioned isn't as great. I'm absolutely positive the last time I set the base timing was when I installed the Fluidampr.
(I apologize for all the thinking out loud ****, but it's helping me work through this.)
I'm tempted to leave the base timing at 5.9 and start all this over from scratch. For discussion purposes, let's assume that the base timing was actually wrong and 8 degrees is correct, but that change is at least part of what is causing the rpm drop. Should I keep 5.9 degrees of base timing correction, or should I change it to 8 degrees and add 2.1 degrees of timing to some, or all, of the spark map, and THEN start from there?
First off, no one can visually tell the difference between 5.9 and 6, not sure why you ever had anything but a whole or half number in there. Regardless, it's my understanding that the 5.9 was checked and set quite some time ago. I would check and recheck base timing, as long as it's repeatably matching up with 8 offset, I'd keep that.
2 degrees of timing anywhere in the timing map will not cause RPM to drop to zero. Faulty wiring, connections, sensors, ECU, or battery will.
First off, no one can visually tell the difference between 5.9 and 6, not sure why you ever had anything but a whole or half number in there. Regardless, it's my understanding that the 5.9 was checked and set quite some time ago. I would check and recheck base timing, as long as it's repeatably matching up with 8 offset, I'd keep that.
2 degrees of timing anywhere in the timing map will not cause RPM to drop to zero. Faulty wiring, connections, sensors, ECU, or battery will.
I agree completely. I'm home now, working to get her into the garage before the thunderstorms hit.
Sorry for being late to the party. In the first .msl log posted, you have a lost sync event at ~1327 sec, reason is code 32. Then in Sunday's log, you've got more lost sync action where it really dropped out...
Code 31 is 99-00 Miata - 2 cams not seen
Code 32 is 99-00 Miata - 0 cams seen
Seems to me the codes mean the same thing LOL, not sure what the difference is but both pointing to an issue with the cam angle sensor, not uncommon on NBs.
Wow. I completely missed/misread that. I've had cam sensors fail before. The car bucks while it loses and regains power, and I didn't have any of that. I have a new cam sensor on hand.
Now I have to figure out why those drag race markers are occurring.
Nice catch, I thought I looked at lost sync and didn’t see any, took forever just to find the zero rpm while he was still moving, dunno how I missed that.
pays to have multiple eyes I suppose.
fyi, and not sure if this works on MS, but I just put a 36-2 trigger wheel on a link, car lost cam sensor on track, and I barely felt anything. Just caused vvt to stop working. So if you’re not already, you might consider switching to save track time.
I swear I never felt anything like the cam sensor failures I have had in the past. They were always violent. I'll be more thoughtful next time.
I wish I'd thought about the 36-2 wheel when I was doing the timing belt. I assume since the Fluidampr is using the OEM trigger wheel, that the OEM version of the FM wheel is what I'm looking for?
Is it safe to also assume the failing cam sensor is my problem and I don't need to start poking around under the dash checking wiring?
05-26-2024, 09:32 AM
Engine went into Overrun at 3000 rpm and 14 mph
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