Compression Test Question

[bambino]

Ah. I get it. It checks starter power usage to check which cylinders are "harder" to crank, and infers relative compression from that. So it's not an actual compression test... just a comparison. (Shrug)... probably okay... not as informative as a full compression test (which would show you if all cylinders are low) or a leakdown... but relative compression is actually what you're usually looking at when performing this test, anyway.

i have this machine to quickly isolate the problem ,so by doing a relative compression test ( that takes less than five minutes of my time , same as diesel engines 4 cyl. or 8 cyl.) i will be able to focus into some other systems

just imagine how long does it take to do a diesel compression test. specially V8'S

the reason why the high ignition pick-up is hooked -up to plug wire #1 is to be able to pinpoint which cyl . is not performing properly

[bambino]

*bambino

interesting gadget you got there ... would you kindly show us an actual crank-current waveform?

sure no problem .

i'm going to get some of my saved files for you as soon as possible

[bambino]

[quote=kinyo;1150413]*bambino

interesting gadget you got there ... would you kindly show us an actual crank-current waveform? [/qu

ill have to check my uploading procedure , it's not working right

[bambino]

*bambino

interesting gadget you got there ... would you kindly show us an actual crank-current waveform?

[IMG]http://i442.photobucket.com/albums/qq144/bambino_08/starterastradiesel-1.png[/IM

here are some waveforms you have requested

[4JGtootsie]

Very interesting!

[niky]

Hmmm... interesting toy... I wonder what it'd cost to bring in here...

[kinyo]

interesting indeed!

the third image do show one cylinder is practically not doing any compression ... also shows the inrush starting current ha ... up to 400A pala

what does the first image show? why the negative figures on the vertical scale?

i've checked the pico website ... a basic kit is priced some $1,300 ... not for a diyer, but oh how i would love to have one! for now i would just contend my self with an AC/DC clampmeter with analog output for my analog oscilloscope

i've actually been visiting pico website in the past ... they started with simple A/D converters for the PC, basically turning the PC into a digital oscilloscope ... i knew they have promising products ... and here it is

[bambino]

hmmm... Interesting toy... I wonder what it'd cost to bring in here...

i bought my complete set for roughly usd 4,500.00

that includes the 3000 series picoscope kit and the first look sensor kit . You're not gonna regret getting this .

And that includes the tutorial .

Now it's also capable of testing the overall engine performance

by just starting -up the car and let it idle

and it will be picked up from the battery (hard to believe but it's very accurate)

[bambino]

very interesting!

i read that you work with diesels and this machine is perfect for it

you have'nt seen the misfire diagnostics capability of this amazing tool and the test will only take 5 minutes or less

considering the precise mechanical diagnostics

[bambino]

interesting indeed!

The third image do show one cylinder is practically not doing any compression ... Also shows the inrush starting current ha ... Up to 400a pala

what does the first image show? Why the negative figures on the vertical scale?

I've checked the pico website ... A basic kit is priced some $1,300 ... Not for a diyer, but oh how i would love to have one! For now i would just contend my self with an ac/dc clampmeter with analog output for my analog oscilloscope

i've actually been visiting pico website in the past ... They started with simple a/d converters for the pc, basically turning the pc into a digital oscilloscope ... I knew they have promising products ... And here it is

it's good to have one specially if you do volume diagnostics

you will be able to analyze the result frame by frame precisely.

It will pay for itself

i used to have analog testers but i traded most of them
and there is still one left but it's been parked in my house a few years now.

If you are interested of some more latest tools and equipment

just let me know and i will e mail it to you how to build it .

Or some latest techniques that i can share ( e mail only)

i built one of my prized testers myself and alot of independent garages are coming in my shop to get the problem cars diagnosed