Unexpected missing tooth cause ?

[lysyfm]

New software helps. Everything works fine. Thanks!

[j.g.]

Hi,
I'm having the same probem (unexpected missing tooth) on my car and i have spend many hours to solve it without success...
Specificly, I changed the cable of my vr sensor to a full shielded 2x1 cable and the problem just 'moved' about 800-900 rpm higher(from 4900 to 5800).
I tryed to turn on pull up resistor as other members recomend, and the car shuts down and ecu resets then(seems logical to me).
My tps seems to be ok (no shortcutting).
I did the firmware update as you recomend and the random 'missings' dissapeared at low rpm, so it helped a little but seems to have another problem too.
Could that be a 'noisy' alternator or something else?
I attach my last log hopping someone can help
thanks in advance, John.

[Jadzwin]

In new firmware (1.174) there is an option for primary trigger to change VR sensitivity over user defined RPMs (VR sensitivity switch)
Try this option

[j.g.]

I missed that
I'll try this today, sounds promissing

[j.g.]

I tried this today, with no results... when I adjust the sensitivity to any lower rpm (than default),the problem occours at even lower rpm..I use 1,173 firmware &softare whitch has that option too.
Another thing I noticed, is that the laptop disconnects immediately, when the problem occcours, so I cant log it.
What else can cause that problem?
Should I update to 1,174 ?

[Jadzwin]

Sounds like grounding problem (if the laptop disconnect) or heavy noise.
Do you have osciloscope ? How are grounds connected in your car ?

[WHPZach]

I tried this today, with no results... when I adjust the sensitivity to any lower rpm (than default),the problem occours at even lower rpm..I use 1,173 firmware &softare whitch has that option too.
Another thing I noticed, is that the laptop disconnects immediately, when the problem occcours, so I cant log it.
What else can cause that problem?
Should I update to 1,174 ?

You could very well be having problems with your ignition system leaking high voltage. Are your wires/boots in good condition, no signs of arcing? Are you using resistor type spark plugs?

[j.g.]

Grounds are connected from ecu to cylinder head and from there to chassis. My multimiter shows '0' resistance from anywhere to ground pins of emu.I will check the oem grounds to be sure about them too.My coils are grounded to engine head(as the other grounds), but at a different spot.Should I relocate any of these?
If you take a carefull look at my first log you'll notice that exactly same thing happens to knock sensor chanel, when rpm rises, so I'll start by checking the alternator as it seems to have noise everywhere.
The alternator itself is a bosch 65A and if i remember weel, it has a noise filtering capacitor.I think that this can be the cause , correct me if I'm wrong.I also purchased a suppressor type capacitor at 2,2mf 230vac(don't know if I can find the same as the oem..), can i use that instead of the original, or connect it via B+ & ground keeping the other as it is?
Unfortunately i dont have an oscilloscope, so I will test/run it without the D+ cable connected, to see what happens and point the problem, before doing anything else.
As far as the plugs, they aren't resistor type. I'll swap them if my alternator isn't the fault.
Thanks for your advices I'll post any udate

[WHPZach]

Grounds are connected from ecu to cylinder head and from there to chassis. My multimiter shows '0' resistance from anywhere to ground pins of emu.I will check the oem grounds to be sure about them too.My coils are grounded to engine head(as the other grounds), but at a different spot.Should I relocate any of these?
If you take a carefull look at my first log you'll notice that exactly same thing happens to knock sensor chanel, when rpm rises, so I'll start by checking the alternator as it seems to have noise everywhere.
The alternator itself is a bosch 65A and if i remember weel, it has a noise filtering capacitor.I think that this can be the cause , correct me if I'm wrong.I also purchased a suppressor type capacitor at 2,2mf 230vac(don't know if I can find the same as the oem..), can i use that instead of the original, or connect it via B+ & ground keeping the other as it is?
Unfortunately i dont have an oscilloscope, so I will test/run it without the D+ cable connected, to see what happens and point the problem, before doing anything else.
As far as the plugs, they aren't resistor type. I'll swap them if my alternator isn't the fault.
Thanks for your advices I'll post any udate

Swap your plugs first.

[j.g.]

I swaped my plugs today with resistor type and there is a significant improvement, but still does the same thing after 6000 rpm.(first time i saw the shift light flashing rev limiter is set at 6400 and the control range at 100rpm, unfortunately i can't reach it, but we're close)
I didn't have time to log it, but i noticed that the 'check engine' light isn't powered after 5k. Before it was always on after that rpm, indicating knock, so now its definately better.
I'll try to reduce the dwell time a little , see what happens and test the vr sensitivity option again.
I'm using 9125601 volvo cois and the dwell times are the lowest(6A) from the table I'm attaching.I found that table online, can anyone confirm those settings?
Does these coils need a suppressor on their power supply

[Jadzwin]

The numbers look resonable.

Please post the log here we will be able to help you for sure.

[j.g.]

I don't have a log with the new plugs, I'll post it as soon as I can, (probably on Sunday or tomorow if possible), but I i haven't change anything since the last posted one.
Thanks a lot

[j.g.]

Today I finally had some time to log it. The disconnection problem seems to be solved with the new plugs.
The unexped missing tooth issue appears at 10:30 and 13:10 on the log.
I tested to disconnect the altenator (d+ cable off) and same thing happened (didn' logged that...), so I think thats not the cause of this situation.

[Jadzwin]

Try 10K resistor in series with primary trigger input. And please put here your calibration

[Paulo11]

Hi guys, I have some "Missing tooth" problems. Looks random and i have no idea what causes it. Everything it´s new(senzors and harness too). Here is my log and scopes.

[Paulo11]

Problem solved- new hall senzor wasn´t good.

[j.g.]

Try 10K resistor in series with primary trigger input. And please put here your calibration

The resistor solved the problem .Thanks a lot for your advices!
When u have some time please take a look at my calibration and log to help me about dwell times, just for being sure about them too.