Search found 66 matches

by Valhalla
Fri Jul 05, 2013 11:28 pm
Forum: Case studies
Topic: Jaguar S-Type 2.7D with hesitation at idle
Replies: 14
Views: 31029

Re: Jaguar S-Type 2.7D with hesitation at idle

Can this pressure drop shown here be attributed to the injector? It seems to occur over a large amount of crank degrees where most of the time the injector is closed. FF Yes, the pressure drop is inevitable on each injection, as the injection itself will consist of a finite volume of fuel that has ...
by Valhalla
Thu Jul 04, 2013 11:30 pm
Forum: Case studies
Topic: Jaguar S-Type 2.7D with hesitation at idle
Replies: 14
Views: 31029

Re: Jaguar S-Type 2.7D with hesitation at idle

I agree with Robski about nice use of FRP sensor information. This have given me an idea for the Vivaro problem that still lurks somewhere in my schedule (if I get to work on it again...) and is something else to back-up a physical spill-return volumetric test for each injector on the fuel system. T...
by Valhalla
Sun Jun 30, 2013 12:11 am
Forum: Case studies
Topic: It’s not always about diagnostics....
Replies: 8
Views: 30662

Re: It’s not always about diagnostics....

It's interesting that there is an approximate relationship between frequency and amplitude of the trace on one cycle, but not on the opposite cycle (whatsoever). The pattern from cycle-to-cycle appears similar, so is it a coincidence only that it fits the inferred piston speed? As mentioned, I would...
by Valhalla
Mon Jun 24, 2013 10:41 pm
Forum: Case studies
Topic: Lean misfire – Have you checked the coils?
Replies: 8
Views: 22500

Re: Lean misfire – Have you checked the coils?

I'm impressed. I would have never thought of checking for coil failure with a lean misfire - quite the opposite. It would seem a bit premature of BMW to shut a cylinder down so fast on a coil diagnostic, you would have though a few cycles of injection would not have killed the catalyst outright, and...
by Valhalla
Tue Jun 18, 2013 11:00 pm
Forum: Diagnostic discussion
Topic: Do I have conclusive evidence
Replies: 22
Views: 31524

Re: Do I have conclusive evidence

Andy, Is the dropout that you are referring-to the PWM line (blue trace in your logs above) when it goes to a duty cycle that is not 0% ? I am not sure that there is necessarily a problem with these traces. What is quite common for this type of motor control is for a 0% or 100% duty cycle to be appl...
by Valhalla
Sun Jun 16, 2013 11:03 pm
Forum: PicoScope 6 Automotive software
Topic: MAF Signal
Replies: 19
Views: 24162

Re: MAF Signal

Would it not be better to graph the frequency like this? This can be done with any PicoScope capture. You don't have to have a 4000 series. In this example, freq(B-2) Range 0 to 1000 Hz. Tom Roberts Autonerdz.com THE PicoScope Automotive Authority in North America. It's much better graphing the fre...
by Valhalla
Sat Jun 15, 2013 11:45 pm
Forum: PicoScope 6 Automotive software
Topic: MAF Signal
Replies: 19
Views: 24162

Re: MAF Signal

Please have a look at the attached post. If you could work it out it would be great. Also, if you could show me the workings for future ref that would also be great. Simon, As everyone points out correctly, your sample rate is way too low - you should be sampling at no more than 25us for looking at...
by Valhalla
Sat Jun 15, 2013 10:10 pm
Forum: PicoScope 6 Automotive software
Topic: MAF Signal
Replies: 19
Views: 24162

Re: MAF Signal

Robski wrote:look in automotive presets it is in there.........
Where it states that the frequency option is available from 4000series Picoscope onwards. If you look at Simon's waveform again, the properties show his scope to be 3000series. That could be why Simon cannot find this.
by Valhalla
Wed Jun 12, 2013 11:43 pm
Forum: Diagnostic discussion
Topic: 2008 Vauxhall Vivaro piezo injector currents
Replies: 17
Views: 32856

Re: 2008 Vauxhall Vivaro piezo injector currents

Make sure you remove the full scuttle panel and reseal it other wise water will just fill the cylinder head back up. I've also PM'ed you about programming the injector Thanks, PM responded. What I have also done with the plastic cam cover is to run a bead of silicon grease around the rubber seal/s ...
by Valhalla
Wed Jun 12, 2013 5:28 pm
Forum: Diagnostic discussion
Topic: 2008 Vauxhall Vivaro piezo injector currents
Replies: 17
Views: 32856

Re: 2008 Vauxhall Vivaro piezo injector currents

Yes, the same... The well moaned about scan tool continues to amaze - not very much. It seems it shares several traits with other Chinese clones of european scan tools, in that neither it nor the Chinese OP COM can communicate with a 2008 Vivaro van, not one running an F9Q engine, without throwing o...