Auditrigger research

Here I'm going to add info about som auditrigger research I have made. The so called 135 trigger system or (c270).

At first a began to look at this picture.


I then realize the home trigger have a frequency which is half of the primary trigger. That means if you superimpose the home signal over cranksignal you should in theory get a 135-2 triggersignal.

Small other things to notice:

1. Original home signal is inverted to crank-signal. Possibly for superimposing signals.

2. Same type of signal has been seen on Toyota 24/2 Distributor also with inverted "home" signal.

3. Small interference between crank and homesignal is no longer an object for filtering since they are merged.

I also find a schematic over a Motronic system from a Porsche with have a similar system (no Cam-trigger).

I copy the input circuit to pspice and began to simulate signals and as an output I got a 135-2 signal. I will describe this better later on.

I also have made prototypcard with components to test in a real car. More info to come.

Porsche motronic schematic:

VR trigger problem

Yesterday I was away on a quest for a car that encounters triggerproblems.

When I hook up the oscilloscope on the trigger signal a found this:


And here is one for the missing tooth:


This is 60-2 trigger and at the time the picture was taken the oscilloskop was directly connected to the VR trigger and no other electrical equipment was connected to the engine.

So my question is why is there so much noise on the signal?

I also figured that the signal got cleaner when the engine was inbetween two compression storkes. That means lower work for the starter.

Here you can see the part which the signal is cleaner:


Could it be the starter that is faulty?

The starter was now changed, but no luck, there is still

lot of noise on the VR-signal.

Does anybode encountered the same problem?

Answer: I had very similar problem once. With auditrigger. Yes it was starter. But what is physics under this - I don't knew! Someone else? GintsK?