I have been racing this car in it’s current setup for an entire 2024 season with absolutely no issues.
At the first race of this year the car ran great for all sessions but after I pulled off the track for the last time, the car died. I was able to run it enough to load into the trailer but now I cannot get it to run. I’ve tried everything except changing my settings in the program. It wants to start but falls off immediately, giving me the “UMT” message in the log. I’ve checked the wheel, changed sensors, gap, ground, continuity and have run out of things to look for. Every once in awhile, say after I change the air gap, the car will idle just fine, even rev up. But when I let off throttle it dies and sends me “UMT”. Then, even with the same gap, it won’t start at all and dies.
I’m getting fuel, spark, etc.
I’m thinking it had to be some sort of event that happened during the last race, either physical or electrical.
After cycling the main power supply/kill switch, the motor will idle normally. But then, after 30-40 seconds it will falter and die. The scope proves this. There is a build up of interference that creates the missing tooth signal that stays in the system and then leaves over time/power cycle. If I try to restart the motor right away, it will not idle and goes straight to “UMT”.
What would cause this to happen? I’ve eliminated all possible noise sources and tested all shield grounds.
Is there even a possibility of an actual EMU Black internal failure?
Hi Greg, I am working on that. I saved a scope log but can’t get past the regular desktop page.
The scope clearly shows a build up of “missing” teeth between the skip tooth. Stay tuned…
Sorry, I don’t know what a calibration file is.
For some reason, I am not able to import the scope file.
ECUMasterusa has answered my inquiry but I still don’t have an answer. They are saying I’m getting the UMT as a result of low rpm. This does make sense but it doesn’t solve the problem.
If the ignition has been off for five minutes or more, the motor will idle for 30-40 seconds, start to falter, then die. If I try again right away, it won’ idle at all. It’s as if there is some sort of “build up” that accumulates and creates interference/noise. Then dissipates after a rest.
Air gap is now at .032" but I’ve tried everything there. It ran all last year at .024 and never failed.
I have continuity on the shield wire.
My car and I are 97456.
I’ve ordered a new EMU Black in desperation. At least that will troubleshoot to the end component.
My friends in Canada need a new unit for another race car build so I’m not throwing money away.
Another source has pointed out a possible cam belt stretch/tensioner issue, Doubtful but worth a look.
Keep those ideas coming! THX
calibration file or tune file. like the settings that’s saved on the ecu.
The logs are useful but I also want to see what the trigger settings, ignition, IO etc. Its like a picture is worth 1000 words, having both paints a stronger picture then asking a few questions.
Found it everyone. I have a bad external MAP sensor. I re-routed to the ECU internal MAP and fixed all problems instantly. Selling the unboxed ECU to my buddies.
Lesson learned: “Unexpected Missing Tooth” is just the result of the real problem. MAP was screwing with the tune and everything else followed.
Thanks for all the helpful advice guys/gals. I’m obviously new to ECUMasters and tuning in general but will continue to learn as I go. Great forum.