Voltage instead of current for relative compression test

More
5 years 9 months ago #21712 by WisdomWarlord
Has anyone tried setting their scope for a min of something like 8vdc and a max of like 12, and then crank the engine over to see if you get a useful waveform for doi G a relative compression test? Is it a reasonable thing to do if you don't have a current probe? I don't have access to a car with compression problems, so I wouldn't get to see the behavior.

Please Log in or Create an account to join the conversation.

  • Noah
  • Noah's Avatar
  • Offline
  • Moderator
  • Moderator
  • Give code definitions with numbers!
More
5 years 9 months ago #21717 by Noah
Good question!
Voltage measurement is just fine for relative compression testing. Andy has gone over the set up in the past in the forum.
Remember that voltage and current are Inversley proportional, so the valleys of the voltage waveform will be representative of the peaks of an amperage waveform. Many scopes will have a setting to invert the waveform for you.

"Ground cannot be checked with a 10mm socket"

Please Log in or Create an account to join the conversation.

  • Noah
  • Noah's Avatar
  • Offline
  • Moderator
  • Moderator
  • Give code definitions with numbers!
More
5 years 9 months ago #21718 by Noah
Also, you could create a compression problem by removing a spark plug ;)

"Ground cannot be checked with a 10mm socket"

Please Log in or Create an account to join the conversation.

Time to create page: 0.221 seconds