Search found 319 matches

by Fat Freddy
Thu Jul 06, 2017 12:48 pm
Forum: Diagnostic discussion
Topic: Individual cylinder valve timing errors
Replies: 18
Views: 6090

Re: Individual cylinder valve timing errors

jamesdillon wrote:Here's an image from our Oscilloscope Masterclass training course showing valve clearance and valve timing relationship as mentioned above..
I was thinking of the nose/peak of the cam being worn only. But in the real world that's pretty unlikely.
by Fat Freddy
Thu Jul 06, 2017 12:36 pm
Forum: Diagnostic discussion
Topic: Individual cylinder valve timing errors
Replies: 18
Views: 6090

Re: Individual cylinder valve timing errors

Hi FF Your assumption regarding the engine drawing on a closed throttle may not be the case. Some engines, during cranking, hold the idle air control valve wide open, thus the incoming air flow circumnavigates the closed throttle via the idle air 'loop'. Cheers James. Hi That is correct. But in the...
by Fat Freddy
Thu Jul 06, 2017 2:43 am
Forum: Diagnostic discussion
Topic: Individual cylinder valve timing errors
Replies: 18
Views: 6090

Re: Individual cylinder valve timing errors

Still playing 'Devils advocate' here. :) Re "Cylinder 2 excessive intake valve clearance (Channel B Magenta)" I'm not convinced about the reasoning behind “Why is the compression higher on cylinder 2 with excessive valve clearance?” And the theory "I originally thought that the compressions may have...
by Fat Freddy
Sun Jul 02, 2017 6:53 am
Forum: Diagnostic discussion
Topic: Individual cylinder valve timing errors
Replies: 18
Views: 6090

Re: Individual cylinder valve timing errors

Another excellent presentation Steve and appreciate the effort that goes into doing them. I'm still chewing them over but with regards to: I have racked my brain why the waveform looks like this (between 360 and 540 degrees) and my gut feeling is the piston is required to travel further down the cyl...
by Fat Freddy
Tue May 30, 2017 10:48 pm
Forum: Diagnostic discussion
Topic: Unusual o2 sensor waveform
Replies: 6
Views: 1793

Re: Unusual o2 sensor waveform

TBH I would just move on from this whole O2 diagnosis thing regardless of scan tool, scope.

Personally I would apply a maths channel to the CAS with a sync to 1 to see what cylinder/s is/are playing up and go from there. Using battery -'ve as gnd.

HTH
FF
by Fat Freddy
Tue May 09, 2017 8:55 am
Forum: PicoScope 6 Automotive software
Topic: Frequency drop outs.
Replies: 4
Views: 1032

Re: Frequency drop outs.

Thanks for the info there Martyn. Good to know. :)
by Fat Freddy
Mon May 08, 2017 12:52 pm
Forum: PicoScope 6 Automotive software
Topic: Frequency drop outs.
Replies: 4
Views: 1032

Re: Frequency drop outs.

Thanks Martyn. I had not tried that. A handy tip to know. :D

But I could not get it to work on the other example here. topic16831-10.html
So what am I missing?
by Fat Freddy
Mon May 08, 2017 1:40 am
Forum: PicoScope 6 Automotive software
Topic: Frequency drop outs.
Replies: 4
Views: 1032

Frequency drop outs.

Has there been any comment from the Pico team anywhere about the frequency graphing drop outs as mentioned here: https://www.picoauto.com/support/topic16831-10.html that I have missed. It's a reasonable common thing. Apply Freq(A) to the file located here https://www.picoauto.com/support/viewtopic.p...
by Fat Freddy
Tue May 02, 2017 11:51 pm
Forum: Diagnostic discussion
Topic: Sensor, wiring or ring ?? (Digital)
Replies: 20
Views: 6168

Re: Sensor, wiring or ring ?? (Digital)

I realised at times the signal voltage would fall outside of the voltage I had written into the maths channel. So i fiddled with it and changed the colours and yet it STILL shows the drop outs on frequency on the graphed maths channel. I have left all the cursors in place on this capture to show yo...
by Fat Freddy
Thu Apr 27, 2017 11:22 pm
Forum: Diagnostic discussion
Topic: Nissan X-Trail Non-start Timing Chain?
Replies: 11
Views: 14275

Re: Nissan X-Trail Non-start Timing Chain?

What I can say is a stretched Nissan chain, even when it starts will cut out. Fuel, spark?? the customers mechanic who replaced the head gasket says it wont be. Coarse he did. The statement was probably proceeded with "What's he checking that for? I've already done it". I'll be surprised if it is no...