Used my scope tonight for the first time!

Ask for and share advice on using the PicoScope kit to fix vehicles here.

Re: Used my scope tonight for the first time!

Postby Wally » Fri Jan 27, 2012 11:41 pm

GRUSS wrote:Ps what do you run the LC-1 on?


A 4.6 Ltr V8 Quad Cam Ford, Just over 320 Bhp and around 320 ftlb torque, in and AC Ace Brooklands.
Using a DTA Ecu and LC1, get around 26 mpg driving normally. Quite happy with the engine but we need to sort out the handling to give a bit more confinence at speed.

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Re: Used my scope tonight for the first time!

Postby GRUSS » Sat Jan 28, 2012 7:57 am

Very nice, American muscle aye! :)

Was I remotely close with my answer about voltages and 14.7:1?
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Re: Used my scope tonight for the first time!

Postby GRUSS » Sat Feb 04, 2012 5:11 pm

I took my scope to work this week and have used it a few times and has come in very useful with a canbus problem on a astra H. I had no comms with the high speed modules.. engine ecu, ABS, Steering and CIM and the engine wouldnt run.I did a quick resistance check at the DLC which gave me 60 ohms. I then hooked the pico up and could see that both the high and low were showing 12v. In the end i traced the fault to a shorted PAS pump problem. Once upplugged the waveform looked like it should do and the vehicle would start and allow comms.

I stopped behind today and had another play with my o2 sensor on my car, i ensured it was warm and set the scope up. I revved the engine to try and get the waveform to start switching....

The attachment 02 sensor saturday.gif is no longer available


i have tried to upload a psdata file but it wont let me?

I unplugged the sensor and just probed the actual sensor harness side but it was still hardly doing anything, i need to try another one really. I did however check the wideband gauge whilst it was unplugged and at idle it was still reading approx 14.7:1 so it must be using the map sensor...?

Any opinions would be great, next week i'm going to try it on some modern vauxhalls and have a looks at the 02 sensors.
Attachments
o2 saturday revving.gif
02 sensor saturday.gif
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Re: Used my scope tonight for the first time!

Postby Robski » Sat Feb 04, 2012 6:08 pm

I don't know what your aiming for here with this O2 sensor ?

If you want to see its reaction force it rich or lean & see if it swings ?
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Re: Used my scope tonight for the first time!

Postby antthecat » Sat Feb 04, 2012 7:07 pm

I would recommend also to use a longer timebase usually 1s/division is what I use.
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Re: Used my scope tonight for the first time!

Postby GRUSS » Sat Feb 04, 2012 7:16 pm

Robski wrote:I don't know what your aiming for here with this O2 sensor ?

If you want to see its reaction force it rich or lean & see if it swings ?



If I could upload the psdata file you can see it doing something when I rev the engine. The whole trace moves upto 400mv and attempts to start swinging...
If the sensor is dead then it will put the ECU into open loop, but the wideband doesn't reflect this. Maybe I should try running it on the road with the sensor disconnected and monitor the AFR's.

My other thoughts are that if it is in open loop (like when the engine is first started and the O2 sensor is cold) then its using the map sensor all the time.

I'll get a universal single wire sensor and fit it.....
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Re: Used my scope tonight for the first time!

Postby Martyn » Mon Feb 06, 2012 7:11 am

I will check why your psdata files can't be uploaded, in the meantime just zip the file and upload it.

Edit: How large is your file ?
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Re: Used my scope tonight for the first time!

Postby GRUSS » Tue Feb 14, 2012 7:06 pm

Ok got my new universal o2 sensor this week and stayed behind at work to fit it, after using some extreme heat and a tap to clean the threads up the new sensor is in!
I only had 5 mins before the workshop got locked up but i managed to take a couple of captures of the new sensor....



I've been playing around with the resolution and the low pass filter settings to try and clean up the waveform as i was still getting quite a bit of interference from the engine. I'm quite happy with my first real scope diaganosis though :)
Thanks for all the help guys!

The difference in drivability stands out straight away, pulls loads stronger when accelerating and generally feels more responsive!

Couple of questions... how do i save the file as a jpeg? cant seem to see the jpeg option in the drop down box?

Obviously i've played around with the settings but are these the best?

many thanks :D

See the results below! :D
Attachments
new sensor with filter off idle.gif
original sensor with filter off idle.gif
new o2 sensor with modded filter settings.psdata
(450.21 KiB) Downloaded 203 times
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Re: Used my scope tonight for the first time!

Postby antthecat » Wed Feb 15, 2012 8:24 pm

New o2 sensor looks like it is working, as you say performance has improved so a good fix.
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Re: Used my scope tonight for the first time!

Postby GRUSS » Wed Feb 15, 2012 11:26 pm

antthecat wrote:New o2 sensor looks like it is working, as you say performance has improved so a good fix.


Thanks :D
Yeah it's certainly improved things! Ran alot smoother this morning and feels in general alot better. This was always going to be the first proper job I used my scope for and it's proved it's self already. I'm happy :D
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