Re: Oscilloscope for auto dx

On the road portability will come in very handy.

At least a two channel with an adjustable trigger level on one channel, volts range adjustment down to at least 50mv per division (or less) in case you wind up purchasing some accessories which output fairly low signal voltages i.e., a low amps probe. Glitch capture can be handy, but not an absolute necessity. Delta time and delta voltage ability is nice but not absolutely necessary

As John said, darn near any frequency range will work on automotive. If you wind up with a digital, sample rate becomes more important WRT whether or not the pattern will archive when testing higher frequency signals (some MAFs for example).

Secondary pattern pick-ups are capacitive, the #1 trigger (to sort the order) can be inductive however. Go to:

The have lots of options WRT hook up configuration, these guys should have any and every accessory you'll need.

Once you've done a compression test with a lab scope, you'll never go back! (thought provoking, 'eh?)

snipped-for-privacy@yahoo.com (Lance Morgan) wrote in news: snipped-for-privacy@posting.google.com:

I'd skip this old scope,IIRC,a 321 model,unless it's free,or close to it.

For a while,TEK offered a digital LCD scope/multimeter with a 5 Mhz bandwidth,and it was designed for automotive testing.THM something. Fluke also has a couple of battery models.Leader and other companies also made some small LCD scopes suitable for this.

To bad you need a small portable scope. I used my "abundant on E-Bay" Tektronix 465B to characterize my ignition for a tachometer gate design. The

There are scope modules for laptops (if you have a laptop).

Dave M.

There are two ways to do a compression test with a lab scope.

Method 1 gives a relative compression test. It's done with a high-amp inductive pick-up on the battery cable to the starter, the amps probe is connected to channel 2, on channel one an inductive pick-up is connected to #1 sparkplug wire for synchronization. With the time base set to display the amperage waveform for all cylinders, the engine is cranked. Cylinders with weak compression will draw fewer amps as displayed by the trace.

Method 2 involves a pressure transducer that outputs a voltage signal relative to pressure. The transducer is connected the same as a conventional compression gauge is into the sparkplug hole, the engine is cranked, the labscope displays a waveform of the cylinders compression with the added advantage of the pressure being displayed over time. Method 2 can also be utilized when performing a running compression test. Since the pressure transducer responds much faster to pressure changes than a mechanical gauge can, the results are much more revealing and much more accurate.

Then there's using a -vacuum- transducer for measuring/viewing intake vacuum instead of a mechanical vacuum gauge... Wouldn't being able to see the vacuum event for each individual intake event be a better diagnostic tool than the old fashioned gauge method?

Lance Morgan wrote in news: snipped-for-privacy@digitex.net.unknown.dom: