Hi guys its my first post so please be nice . I have a Nissan Pulsar N16 QG18 engine. The problem I have is I think the varable cam system may be jammed in one position ????? I have only just got my Pico so im not real sure on how to use it yet but can I use it to check if the cam timing is out or the varable timming is jammed????
Thanks Ron...
Hook into ch 1 into cam sensor, ch 2 into crank and ch 3 into a synchronising signal (injector or ignition).
Set the trigger on ch3 (rising edge) and the timebase to 200ms (engine takes 150ms to do suck squish, bang and blow at 800 rpm). Move the trigger across the screen until you see two complete crank revolutions.
Next, you can look for a repatitive relationship between the cam and crank (count the crank sensor pulses between it and the cam sensor). Use the cursors to help with this lining up process.
Finally activate the variable valve solenoid (use a scan tool or use a jump wire between the VVT solenoid control wire and earth) and look for the reference you took before to have moved to the left (advancing the intake cam).
It is a bit difficult to explain here, but I hope you get the gist?
Hook into ch 1 into cam sensor, ch 2 into crank and ch 3 into a synchronising signal (injector or ignition).
Set the trigger on ch3 (rising edge) and the timebase to 200ms (engine takes 150ms to do suck squish, bang and blow at 800 rpm). Move the trigger across the screen until you see two complete crank revolutions.
Next, you can look for a repatitive relationship between the cam and crank (count the crank sensor pulses between it and the cam sensor). Use the cursors to help with this lining up process.
Finally activate the variable valve solenoid (use a scan tool or use a jump wire between the VVT solenoid control wire and earth) and look for the reference you took before to have moved to the left (advancing the intake cam).
It is a bit difficult to explain here, but I hope you get the gist?
Let us know how you get on.
Cheers
James.
Hi there! My friend also thinks that his cam system is jammed in one position and we're kinda confused how to fix it. You've given instructions but I hate to admit it, we're kinda noobs and don't know where to start. We're kinda lost about setting the trigger on ch3 and counting the pulses on the crank position sensor between it and the cam sensor. Do you have any pictures or manual so we could better see it? I'll appreciate it.
Hi Guys,
I'm certainly no authority on the Picoscope but just to help you get the ball rolling, I'll attempt an answer.
If you're using the same automotive software that I have, the trigger settings will be along the bottom row of the screen next to the stop/start symbols. You'll only be able to set the trigger from channel c once you have switched trigger from 'none' to repeat eg.
you'll also only be able to trigger from channel c if you've got a 4 channel scope with channel C turned on.
What you're trying to see with the scope capture is the relationship between the crankshaft and camshaft positons.
If the variable timing system is working correctly the relationship will alter.
Here is an example, where I have triggered off an injector voltage signal, in order to stabilise the waveform. It was easier to use an ignition event, but it proved to be unsuitable as the ignition angle wandered too much & the waveform stability suffered. You need to experiment & find what works for you.
As Andy said, the trigger options are to be found on the lower left area of the screen. You can drag & drop the "yellow diamond" trigger cursor for convenience. Use either repeat or auto trigger, they both work in a similar way, although the repeat trigger will not display a capture until trigger threshold is met. If you select "Auto" then the screen will at least draw a waveform periodically, even if the trigger is not met.