Probing Tractor

[JustMeHere]

I need to probe the electronic control unit on my tractor.   We are very suspicious of the control unit.  My question is can the probes absorb the nasty transients I've heard about in automotive environments?   I got a micsig 20xx. 

The signals I want to probe are the start relay and the fuel cut off relay.  There's a solenoid and of course altenator and a starter.  This is a desil.   So no spark plug ddischarge.

[targit]

I use the Micsig differential probe for most automotive stuff, this is mostly because the 4mm banana jacks fit all my back probes and insulation piercing acupuncture probes so switching between DMM and scope is also easier. I have also used the x10 probes that came with the scope and they seem to cope with diesels pretty well - although they are not physically as robust as 4mm type DMM probes. You do need to keep an eye on where you are earthing the probes though, this is where the differential probe also helps as there is no chance of a high current path through your scope.

[Chris Roubis]

I need to probe the electronic control unit on my tractor.   We are very suspicious of the control unit.  My question is can the probes absorb the nasty transients I've heard about in automotive environments?   I got a micsig 20xx. 

The signals I want to probe are the start relay and the fuel cut off relay.  There's a solenoid and of course altenator and a starter.  This is a desil.   So no spark plug ddischarge.

Have you done a pin out test, on the control unit first?

Make sure you have correct voltages and also check you have a good ground.

Then check value of sensors around the engine.

Find a circuit diagram and pinout for your model.

[JustMeHere]

I managed to fix the tractor somehow.   Shaking the wire near the fuse box seemed to do the trick.

[0culus]

I managed to fix the tractor somehow.   Shaking the wire near the fuse box seemed to do the trick.

Yeah, but do you understand why it is working now? Seems like that is a necessary step to ensure it's actually fixed.

[JustMeHere]

I managed to fix the tractor somehow.   Shaking the wire near the fuse box seemed to do the trick.

Yeah, but do you understand why it is working now? Seems like that is a necessary step to ensure it's actually fixed.

Yes.  The fusebox.  I know within an inch of what to look at if it fails again.  I have another tractor that uses the same electronics.  I was able to rule out the relays and control box by swapping things around.