# Unexpected missing tooth & false sec trigger & **URL:** \ **Category:** EMU BLACK / CLASSIC\ **Created:** [July 21, 2026, 9:22pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214 "2026-07-21T21:22:18Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![IDLab06](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@IDLab06](https://community.ecumaster.com/u/IDLab06)\ **Post date:** [July 21, 2026, 9:22pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/1 "2026-07-21T21:22:18Z")
Unexpected missing tooth in EcuMaster… I was convinced it was caused by a sensor that was too small in diameter; sometimes it gets it wrong and reads 40,000 rpm during startup. So this evening I installed a 36-1 in place of the 60-2. Worse still… I’ve tried various filtering solutions (low, mid, high) and thresholds with no results. Tomorrow I’d like to try a 10kΩ resistor in series with the sensor. Does that make sense? I installed a 4.7kΩ pulldown resistor with the 60-2, but it didn’t help. Reading around, I realized that excessive cranking advance on highly compressed engines causes the engine to slow down and could consequently lose teeth. What do you think? ---
**Author:** ![IDLab06](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@IDLab06](https://community.ecumaster.com/u/IDLab06)\ **Post date:** [July 22, 2026, 11:44am UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/2 "2026-07-22T11:44:05Z")
![IMG-20260722-WA0028](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/a/a1b72659c5694645ec4330f91bfd8b36a41c33c5.jpeg) ![IMG-20260721-WA0096](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/1/171d49c9565ac0cc6421aeca13ec4f0e46f4f8b1.jpeg)Above when starting, below when the engine is running ![IMG-20260720-WA0013](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/f/f29ca81cdd31f74341c79ca40de5a1c86596408b.jpeg)I have already done another installation with this trigger, the car runs great ---
**Author:** ![essess](https://avatars.discourse-cdn.com/v4/letter/e/d9b06d/32.png) [@essess](https://community.ecumaster.com/u/essess)\ **Post date:** [July 22, 2026, 2:31pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/3 "2026-07-22T14:31:52Z")
Type of sensor? (looks like a V/R) Access to a oscilloscope? (you might want to look at this in the analog domain) Shielded? Where (and how) are you terminating the shield? Run a sharpie across the tip and reinstall. Make sure there is no collision happening. ---
**Author:** ![IDLab06](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@IDLab06](https://community.ecumaster.com/u/IDLab06)\ **Post date:** [July 22, 2026, 3:13pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/4 "2026-07-22T15:13:22Z")
Yes, it’s a VR. I have to test it with an oscilloscope; the teeth aren’t touching the trigger wheel. Twisted and shielded cable, the shield is connected to pwr gnd together with the others ---
**Author:** ![essess](https://avatars.discourse-cdn.com/v4/letter/e/d9b06d/32.png) [@essess](https://community.ecumaster.com/u/essess)\ **Post date:** [July 22, 2026, 6:18pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/5 "2026-07-22T18:18:05Z")
I know you’re certain of these things, but we’re not. Your shielding description is lacking and it’s not something to nonchalantly throw to the side in a marginal case like this. I’m not sure I can help further. Maybe someone else will give it a go. The oscilloscope will probably have your answer. ---
**Author:** ![IDLab06](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@IDLab06](https://community.ecumaster.com/u/IDLab06)\ **Post date:** [July 22, 2026, 6:31pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/6 "2026-07-22T18:31:43Z")
Excuse me. The shield is grounded to Power ground on the ECU side. ---
**Author:** ![IDLab06](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@IDLab06](https://community.ecumaster.com/u/IDLab06)\ **Post date:** [July 23, 2026, 9:46pm UTC](https://community.ecumaster.com/t/unexpected-missing-tooth-false-sec-trigger/6214/7 "2026-07-23T21:46:21Z")
I’m an ass… The problem was all in the battery voltage, I had 300 rpm in starting but not constant due to voltage fluctuations