I am stunned, that you can diagnose an upper end issue by just looking at the exhaust misfirepulses!!!! These downward spikes ARE the result from the misfire, all they tell you is ..... here was a misfire ..... nothing else. Interpreting exhaust pulses is a very inaccurate science. There are too many variables involved and these pulses can look extremely different on different cars and still they all are in perfectly good working order. They might just have different exhaust connections that influence the outcome. The only thing that you CAN identify is the misfire (sharp downward spike followed by an upward swing) itself, but you knew that from the customer. The same result can be achieved when you hold a Dollar bill against the exhaust of a running engine and during a misfire the bill slaps against the exhaust pipe. Now back to the Pico pressure transducer and diagnosing a valve seating issue: 1) get an in-cylinder cranking scan from several cylinder (including cyl 2, the suspect) 2) get an in-cylinder idle running scan from 3 or 4 cylinders (engine should be warmed up!) 3) get an in-cylinder idle running with the time base set so you can see at least 10 to 15 compression peaks in one screen. Now compare them: If there is a seating issue you probably see the compression peaks on the effected cylinder with varying spike heights. Also the compression peaks, compared with a good cylinder, will show a lower pressure and tower could be unsymmetrical. Next the exhaust pocket will show up rounded and with probably less vacuum than a good cylinder where the exhaust opening can be seen with a pronounced kink in the curve. You might also notice that the exhaust and intake pockets can be at different vacuum levels depending on the valves concerned. As a mechanical engineer the Pico pressure transducer is one of my favorite tool in diagnosis but mainly to help customers to avoid expensive and possibly unnecessary mechanical work on their engines. Greetings
There are a ton of people on the forums with a rough idle on E46/E90 with single cylinder misfire that have replaced everything and still have the misfire. Your video may help them out. These cylinder heads probably have an unknown issue with valve seating problems but not everyone has a picoscope with a WPS500 and your extensive knowledge. Sweet video. Learned a lot!
Maic, yo uso labscope pero no PICO y hay cosas que no las entiendo, como consigues ver el evento de escape de la valvula de un cilindro en especifico ?, lo haces con la compresion relativa con el pico!! dejame saber me intereza si puedes explicarme.
Marcelo Mena claro con mucho gusto. Uso un evento de ignición como sync. En este caso el Cyl 2 que es el que me da el código de avería. En la Mufla uso el sensor de pulsos de pico WPS500 pero también puedes usar el first look sensor. Por experiencia y estudio se que en un motor de 6 Cyl el tiempo de respuesta del sensor en el escape tengo que usar el segundo hump del pulso de escaoe. En caso de ser un 4 Cyl usaría el primero después del evento de ignición y en V8 el tercero. El analysis de los pulsos de escape es más que todo por comparación ya que es bastante diferente de un vehículo a otro. Así que la misma forma del osciloscopio es la muestra. En mi caso se que tengo un fallo en el cyl dos y al ver el evento en el escape me ratifica que hay un problema con la válvula de escape . También use el WPS500 para hacer una prueba de compresión y ahí es súper obvio que hay problemas con esa válvula. Mira los vídeos de Bernie Thompson de Automotive Solutions el es un maestro en el tema. Además busca los vídeos del First look sensor
@@MaicSalazarDiagnostics , thanks Maic for the feedback, i got a second question i hope U can explain me, i just watch a video from Eric O. he make a correlation chain test in 2012 impala 4 cyl.(I believe) in that case when the engine got a variable cam actuator's(int-ex) is necessary disconnected both actuator to check the proper correlation waveform? ....
@@marcelomena78 it is very important to read the technical information of the system you are testing to get familiar and then know if you need to disconnect or not the solenoids to establish a base timing for both cams. I think on Eric's video he did first a cam sensors to crank correlation and notice that they were not moving.
Holá, que tal? 😀 Looking at the green trace, if I had to make a decision, I would be leaning towards a weakening coil. I love your videos and have subscribed to your channel. Saludos, Joe
Andrew K you have to take the time delay in consideration so in a 6 Cyl is two humps after sync. But there is also small issues with other cylinders that have not trigger the DTC.
great video Marc one thing i could recommend is to look at the tailpipe cranking WPS rel compression and intake manifold FLS cranking to differentiate engine mech prob from spark or fuel prob thanks to you
Maic as always! Great diagnostic work! Thank you for sharing. By any chance did you go in cylinder? & was the exhaust waveform running or cranking? Thank you for bringing us along my friend.
Hi Maic, sorry I didn’t fully explain the reason why. Looking at the green waveform , it looks to me as it doesn’t have enough residual energy left compared to the other coils. However , diagnostics on modern vehicles always manage to surprise us. Keep up the excellent work. Best regards, Joe.
This is one thing I love about posting the videos, great comments, and also analysis for me after. I can re-visit the video and learn more. Thanks again
Hi Maic, very nice “tool box” for the PicoScope. Did you put together the “tool box” or did you purchase it from someone? Did you make the supports for the monitor ?
Maic Salazar Diagnostics no problem. Yeah there is so much you can do with Pico. I see things in videos all the time that I forget you can even do. Love the channel! Keep up the great content.
I like your diagnostic approach, you managed to find it even though it's an intermittent mis. This is very advanced level stuff. I have been watching you, newlevelauto, scannerdanner, motoyam82 and you guys are on a different level! When you pulled the dtc report on your autologic, does it automatically look for any DME updates from bmw?
I am stunned, that you can diagnose an upper end issue by just looking at the exhaust misfirepulses!!!!
These downward spikes ARE the result from the misfire, all they tell you is ..... here was a misfire ..... nothing else.
Interpreting exhaust pulses is a very inaccurate science. There are too many variables involved and these pulses can look extremely different on different cars and still they all are in perfectly good working order. They might just have different exhaust connections that influence the outcome. The only thing that you CAN identify is the misfire (sharp downward spike followed by an upward swing) itself, but you knew that from the customer. The same result can be achieved when you hold a Dollar bill against the exhaust of a running engine and during a misfire the bill slaps against the exhaust pipe.
Now back to the Pico pressure transducer and diagnosing a valve seating issue:
1) get an in-cylinder cranking scan from several cylinder (including cyl 2, the suspect)
2) get an in-cylinder idle running scan from 3 or 4 cylinders (engine should be warmed up!)
3) get an in-cylinder idle running with the time base set so you can see at least 10 to 15 compression peaks in one screen.
Now compare them:
If there is a seating issue you probably see the compression peaks on the effected cylinder with varying spike heights. Also the compression peaks, compared with a good cylinder, will show a lower pressure and tower could be unsymmetrical.
Next the exhaust pocket will show up rounded and with probably less vacuum than a good cylinder where the exhaust opening can be seen with a pronounced kink in the curve. You might also notice that the exhaust and intake pockets can be at different vacuum levels depending on the valves concerned.
As a mechanical engineer the Pico pressure transducer is one of my favorite tool in diagnosis but mainly to help customers to avoid expensive and possibly unnecessary mechanical work on their engines.
Greetings
Impressive diagnosis Maic. The customer will both relieved to have an answer and troubled by the repair. Thanks!
There are a ton of people on the forums with a rough idle on E46/E90 with single cylinder misfire that have replaced everything and still have the misfire. Your video may help them out. These cylinder heads probably have an unknown issue with valve seating problems but not everyone has a picoscope with a WPS500 and your extensive knowledge. Sweet video. Learned a lot!
Thank you so much!!
Maic, yo uso labscope pero no PICO y hay cosas que no las entiendo, como consigues ver el evento de escape de la valvula de un cilindro en especifico ?, lo haces con la compresion relativa con el pico!! dejame saber me intereza si puedes explicarme.
Marcelo Mena claro con mucho gusto. Uso un evento de ignición como sync. En este caso el Cyl 2 que es el que me da el código de avería. En la Mufla uso el sensor de pulsos de pico WPS500 pero también puedes usar el first look sensor. Por experiencia y estudio se que en un motor de 6 Cyl el tiempo de respuesta del sensor en el escape tengo que usar el segundo hump del pulso de escaoe. En caso de ser un 4 Cyl usaría el primero después del evento de ignición y en V8 el tercero. El analysis de los pulsos de escape es más que todo por comparación ya que es bastante diferente de un vehículo a otro. Así que la misma forma del osciloscopio es la muestra. En mi caso se que tengo un fallo en el cyl dos y al ver el evento en el escape me ratifica que hay un problema con la válvula de escape . También use el WPS500 para hacer una prueba de compresión y ahí es súper obvio que hay problemas con esa válvula. Mira los vídeos de Bernie Thompson de Automotive Solutions el es un maestro en el tema. Además busca los vídeos del First look sensor
@@MaicSalazarDiagnostics , thanks Maic for the feedback, i got a second question i hope U can explain me, i just watch a video from Eric O. he make a correlation chain test in 2012 impala 4 cyl.(I believe) in that case when the engine got a variable cam actuator's(int-ex) is necessary disconnected both actuator to check the proper correlation waveform? ....
@@marcelomena78 it is very important to read the technical information of the system you are testing to get familiar and then know if you need to disconnect or not the solenoids to establish a base timing for both cams. I think on Eric's video he did first a cam sensors to crank correlation and notice that they were not moving.
BMW would of thrown parts at it left and right. Great job on your diagnosis sir, impressive!
Mcgregor Uncle Dana thank you so much!!
Really nice, good diagnose :)
Holá, que tal? 😀
Looking at the green trace, if I had to make a decision, I would be leaning towards a weakening coil.
I love your videos and have subscribed to your channel.
Saludos, Joe
A great diagnostic video!!! Thank you for sharing. The pressure waveform seems to show problems away from #2 cylinder(trigger).
Andrew K you have to take the time delay in consideration so in a 6 Cyl is two humps after sync. But there is also small issues with other cylinders that have not trigger the DTC.
great video Marc one thing i could recommend is to look at the tailpipe cranking WPS rel compression and intake manifold FLS cranking to differentiate engine mech prob from spark or fuel prob thanks to you
Do you fix anything bro?
I used to work in all brands. Now I am at BMW shop.
Maic as always! Great diagnostic work! Thank you for sharing. By any chance did you go in cylinder? & was the exhaust waveform running or cranking? Thank you for bringing us along my friend.
Angel Garcia I did the in cylinder test but by mistake got erased.
Primero!
Sounds like a vacuum cleaner. How’s the cat
Hi Maic, sorry I didn’t fully explain the reason why.
Looking at the green waveform , it looks to me as it doesn’t have enough residual energy left compared to the other coils.
However , diagnostics on modern vehicles always manage to surprise us.
Keep up the excellent work.
Best regards, Joe.
Thank you Joe. Excellent comment and you are right.
This is one thing I love about posting the videos, great comments, and also analysis for me after. I can re-visit the video and learn more. Thanks again
Do you think spark indexing is important on a BMW? I saw a few forums about it. What's your thoughts on this?
Most definitely. Specially in GDI engines due to the injector been in the cylinder.
Im sorry Maic
Hi Maic, very nice “tool box” for the PicoScope. Did you put together the “tool box” or did you purchase it from someone? Did you make the supports for the monitor ?
Thank you. I got that from Snap on. Is their diagnosis cart.
Instead of zoom on the WPS500x you can also increase the scale of that channel to see more detail.
John Pilgrim yes. Pico scope software is great! Sometimes I forget about all you can do with it! Thank you for the advice my friend. Blessings
Maic Salazar Diagnostics no problem. Yeah there is so much you can do with Pico. I see things in videos all the time that I forget you can even do. Love the channel! Keep up the great content.
John Pilgrim thank you so much
dis you ever get authorization from the customer to open that engine if so what was the findings??
Joel Automotive In action sorry my friend. This was from another shop. I just diagnose it. No more info
I like your diagnostic approach, you managed to find it even though it's an intermittent mis. This is very advanced level stuff. I have been watching you, newlevelauto, scannerdanner, motoyam82 and you guys are on a different level!
When you pulled the dtc report on your autologic, does it automatically look for any DME updates from bmw?
Love the definition that the Pico provides.