If you go back a page and look at both my photos you will see that my trace where it senses the gap is the opposite way around to your picture and also to that in Adrians book.

Is that significant

 

It is significant in that the computer needs to know which edge to trigger on. The above was probably taken from a standalone ECU using the other edge from factory. It is the only one I had stored in my scope.

I'll take a look at the picture.

 

Geoffreys picture looks good.

Geoff

 

"It is significant in that the computer needs to know which edge to trigger on."

It's not like the 911SC distributor ignition, i.e. the 964/993 DME just "looks" for the missing tooth
(no edge triggering) to determine a TDC reference point. Once it sees that, the timing sequence
begins.

 

 

Image 4 is not very clear, but it is very thin whispy faint lines, my guess is, if there were any significant voltage the image would be similar to one of the first 2 images

Dave

 

David,

With the scope probe connected to a battery , Ground on batt -ve and probe on batt +ve , you should see a clean horizontal line , just like when you connect the scope probe ground to the measuring tip .
All I can see is a massive mains induced ,50 cycle noise signal.
I would concentrate on getting to that position first before attempting to measure the crank signal.

Just to be absolutely clear ,the scope measures the voltage between the probe tip and the probe ground. Hope that makes sense.

All the best

Geoff

 

Geoff

The penny has just dropped

I now understand that you have to use the croc clip as well as the probe tip on the one lead. I have just found how to test the voltage on the batteries.

I am just charging my car battery and will have an answer on the voltage in a short while.

Please excuse my thickness

Dave

 

Deleted the last pictures in case they confused anyone.

I will post new ones first no trace , then 9v then 12 v then cranking.

 

 

the last 3 pictures are in real time ie one straight after the other with no break in time at all.

I take it the cranking voltage is between 4 and 6 volts.

 

I have some more photos showing the starting 0 volts at the bottom of the scope screen with 12 volts being near the top.

If you think they will be useful

Dave

 

Dave,
Thats better !! OK, you have a crank signal and its big enough to drive the DME .
How about taking a look at pin 1 ? Thats the ignition module drive . No signal = no sparks !
What you may have to do is reset the scope timebase . Thats the rotary with 1,5,10 mS etc beside it. Try going to 50mS as a starting place .
If you get no signal try unplugging the ignition modules that are back with the coils.

Between us all we will get that motor running !!

Geoff

 

Geoff.

I take it pin 1 is just a weak signal , any Idea what voltage etc it is.

I think i have just tested for a voltage in the past with the multimeter i have never tried to scope it in the tests i have done.

So do i just scope the pin 1 wire with the probe.

Just to recap

1/, I have tested pin no 1 with a multimeter ,no voltage found

2/, Also i sent 12 volts up pin 1 and produced a spark at a spark plug

3/ Changed the coils

4/ I have got dodgy hall sensor wiring , I have had to pair the wires back due to them being split and looking like they were shorting.

5/ had the ecu tested came back ok

6/ pins 18 & 37 ok 12 volts

7 pins 2 & 19 ok for earth

 

Dave ,
Just a little 5 volt pulse so you can leave the vertical gain alone .

Forget the multimeter stuff. Lets see what you get .

Boy , you are working late !

Geoff