MoTeC Global Forum

this is the two trigger signal from MoTec M4 to MSD Dis4....
the motec no fault code...the MSD blinks 3 (Three Blinks: Intermittent input signal)

some pictures of the error:





























thanks for any help

Where is that noise coming from?
That does not look helpful.

Holmz wrote:Where is that noise coming from?
That does not look helpful.

that's a question :

Where is that noise coming from?

Are you trying to run the MSD directly off the Motec ?

Does the engine run ?

And to confirm, this is a scope trace of the Motec's ignition output ?

If the engine is running, is ignition timing accurate ? Is all MSD coil wiring and HT wiring kept well clear of any crank/cam trigger wiring, and better still kept away from all sensor wiring ?

stevieturbo wrote:
And to confirm, this is a scope trace of the Motec's ignition output ?

If the engine is running, is ignition timing accurate ? Is all MSD coil wiring and HT wiring kept well clear of any crank/cam trigger wiring, and better still kept away from all sensor wiring ?

hi,

this is pictures the MoTec ignition output.....

all MSD wiring is keeptd

It is either electrical or magnetic.
Are you running a condenser?
Are all the ECU sensor wires run as twisted pairs?

Holmz wrote:It is either electrical or magnetic.
Are you running a condenser?
Are all the ECU sensor wires run as twisted pairs?

the ref HALL
sync magnetic
no i not running condenser,and not twist the sensor pair...

szabyk RST wrote:

Holmz wrote:It is either electrical or magnetic.
Are you running a condenser?
Are all the ECU sensor wires run as twisted pairs?

the ref HALL
sync magnetic
no i not running condenser,and not twist the sensor pair...

Well...
1) Do you understand why you want to twist the wires?
2) Do you understand why to run a condenser.

I would do #1 first and then see where you are at. Then add the condenser and you will have some before and after examples to help you understand the effect of the twisting and condenser.
It would be augmented by understanding the reason why you do that, but just following the rules gets you to the same place.

Holmz wrote:

szabyk RST wrote:

Holmz wrote:It is either electrical or magnetic.
Are you running a condenser?
Are all the ECU sensor wires run as twisted pairs?

the ref HALL
sync magnetic
no i not running condenser,and not twist the sensor pair...

Well...
1) Do you understand why you want to twist the wires?
2) Do you understand why to run a condenser.

I would do #1 first and then see where you are at. Then add the condenser and you will have some before and after examples to help you understand the effect of the twisting and condenser.
It would be augmented by understanding the reason why you do that, but just following the rules gets you to the same place.

OK, I give the information to the installer

And the mag sensor wires should also be shielded.

hall sensor wiring is less important, but good practice to shield them.

But most important is routing them well away and never parallel to any high voltage wiring.

And as the MSD can trigger the coils at around 500v, these too should be considered high voltage as well as the actual HT leads themselves.

Despite this problem, does the engine run, and is ignition timing as commanded on the map tables ?