Is my sensor getting too old for the job? missing some teeth

[Dangerrous]

This is one of the less complicated setups.

Audi ABZ 1995 4.2 V8 using all original sensors etc...

I'm still learning about all this, but the engine runs and revs, so now it's down to fine tuning and reading posts for clues. But I'm stumped on this one.

The vemstune is red flagging my vr sensor for bad triggering.

I have checked the resistance- 0.95kohms tolerance as per Audi is 0.5-2.0kohms

The sensor ring is as per oem via a sensor ring off the starter ring in the 60-2 config, the sensor is approximately 1mm from the teeth located in the gearbox bellhousing as per Audi, no mods anywhere.
So first step was to analyse what the vems was getting all flusted about:



Okay so the sensor is failing to see a fair number of teeth, why?

So let's have a more detailed look, all fuel is off and the next picture is just on the starter


Anyone got any ideas
cheers
Darren

[gunni]

Are you using it on "falling edge"?

[MWfire]

Trigger analiser is to slow for running engine. Do you have log?

[Dangerrous]

Thanks for the reply, I've configured the vr sensor as per F1 help. I tried a number of things like switching the pos/neg around on the ac signal, just backfired. I'll have another look tomorrow and check all my settings. The sensors are fairly cheap so I don't mind buying a new one.
Here's a picture of the hole in the gearbox for the vr sensor.


Is the sensor ring too for off to one side for pick up, really don't want to attack it with the die grinder to elongate the hole. Fingers crossed. I hope that since I had a good signal when just turning on the starter I should get the same when running.

NB  I tried the sensor at different distances, I got the same result even up to a 3mm gap
cheers
Darren

[Dangerrous]

I'll be able to play tomorrow, and I'll log the result for analysis.
Again thanks for the help so far, it's nice that the engine is running.
With regard to the bit rate, can't I increase the sample frequency? or is it just too basic. The two readings were taken a) at 1100rpm and b)what ever the starter throws the engine over
D

[mattias]

In the triggerlog window you can raise the communication speed (should be obvious) and it will probably handle engine idle speed.

[Dangerrous]

changed the sample frequency, and now perfect, my problem is my cam sync, the vems is faulting as bad second trig, I'm now trying to set the timing but my timing light can't pick up the extension lead from my cop.
Not really a problem, just need to dig up a good lead


Again cheers guys

[MWfire]

Try diffrent edge on cam sync.

[Dangerrous]

The cam sync wheel is OEM to the early Audi's, the hall sensor registers the small slot that's cut out of the cup, changing from rising to falling doesn't work I've tried it, I'm going to move the cup so it's further away from the missing teeth signal from the VR sensor, looking to get it around tooth number 30ish (60-2)

This is the later Audi camsync cup with three slots, mine has just the one.

The picture is from Andy who has written a couple of tutorials on the VEMS ABZ correlation

[MWfire]

You don't need to cut teeth. You can easily filter 3 teeth with option ignore sec trgger after primary n pulse.

[Dangerrous]

Sorry maybe didn't explain clear enough, my camsync cup only has one slot, the later ones had three cut slots, Andy is showing a fellow builder the easiest modification to make the camsync set up pretty straightforward.

I'll have a play tomorrow, I'm hoping to get the project dyno'ed in the next few months, the tuner will correct all my mistakes and I'll learn something, should be fun.
Cheers
Darren

[MWfire]

imho it's simpler to put value 20 then cut 3 teeth.