Pete Meier from Motor Age covers different labscope diagnostic techniques such as relative compression, pressure transducers, and driveability diagnostics.
just bought a used computer and a new cmp sensor , and i still have a code. finally used my scope and found i had a bad new sensor. i just felt lazy and did not want tp use my autel maxiscope, which was sitting in my box for 6 months and never used. i would have been a couple hundred dollars richer. live and learn...i guess i am still old school , lol Thank you for the video
Nice to listen to a humble instructor, who clearly knows what he is talking about. I learned quite a bit in the 2 hrs. Thanks Mr. Meier. Hope people are patient enough to watch the entire program, its worth it! Gonna re-watch this from time to time. Thanks again.
I can't believe its' taken me 2 years to find this. Very, very good course Mr. Meier. I just bought my first scope and this is exactly what I was looking for! Great Course!
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Outstanding information. I use my scope as a last ditch item and this has really opened my eyes to a scope not only being a time saver but a default tool. Scope will automatically come out on all future jobs.
it was hard too learn at first, as I am lazy to study. I took lessons from you tube one at a time and also bought a autel maxiscope. I had wanted to buy a Pico, but i thought i would wait as it was way too expensive for what i was going to use it for. Hope all the guys out there go and get one and learn it, as we were never offered lessons in our workplace or had to buy our own.!!
I have pico 2204 collecting dust in my tool box but i wanna know how to use it. In fact, i have a Honda accord 03 running rough due to something i cannot figure out. Id love to use the scope to check coils output and whatever could cause the car to be possessed
Chad thanks for watching and give Pete a good comment...he appriciates it. If you have not already subscribed to our tstseminars RU-vid channel please do so. thanks
Regarding the relative compression test and the peak being low followed by a high one. It seems to me that the explanation given mixes what is happening during the test, when the cylinder is not firing, with what happens when the cylinder is firing. I would think that during the test, the lack of compression would cause the engine to speed up if anything. if the cylinder had zero compression. If the engine speeds up, then shouldn't the following cylinder take slightly less amperage also?
hey pete just a question when you hooked the scope channel to the fuel pressure sensor on the 5.4 ford triton signal wire did you AC couple the channel to get a better "view" ?
Most systems identify a misfire while the engine is running. That means the source of energy is coming from burning fuel inside the combustion chambers of an engine. When a cylinder misses due to no spark, there would be no power stroke and the crankshaft will slow down because of losing one of the cylinders' power strokes then a misfire will be detected. If the engine that misses is a four-cylinder engine, its crankshaft will spin 90 degrees with no power stroke while also driving a different cylinder's compression stroke in that engine. Your test is showing a six-cylinder engine with one of the cylinders producing low compression being cranked over by a starter motor, which is the source of spinning in this case. Furthermore, the starter is being resisted by good compression strokes coming from cylinders 1,2,3,5,6. These cylinders are resisting the speed of the starter motor (slowing it down) and making it draw an amount of current that is higher than the amount of current drawn by cylinder #4. Since cylinder #4 is not resisting the starter's speed (not slowing it down), it will not need much effort out of the starter because of low compression; thus, the starter motor will speed up (crankshaft will speed up) momentarily, drawing less amount of current as the scope is proving. The firing order for the engine being tested is 123456, so if the starter will speed up (crankshaft will speed up) at cylinder #4 due to weak compression, the cylinder that follows which is cylinder # 5 will have its piston pushed up faster than the rest of the other pistons. As a result, a greater amount of air is going to be compressed (not much air escaped past the piston rings due to the upward movement that was faster). Also, more current is going to be drawn by the starter because of the greater amount of air is being compressed as the scope is showing at cylinder #5. This is how I thought about the compression waveform. I will watch the rest of the video later. Thank you so much, sir.
S SE wow what a good write up...thanks for watching and your comment...If you have not already subscribed yo our tstseminars RU-vid channel please do so. If you are interested in more training please go to www.tstseminars.org...thank you
Jesus thanks for watching and commenting....If you have not already Subscribed to our tstseminars RU-vid channel please do so. Interested in more training? Go to www.tstseminars.org and www.attstraining.com
Frank the membersship fee for 1 year per tech is $75.00 or $250.00 for a shop with 3 or more techs. For more info go to www.tstseminars.org. Thanks for watching.
Frank the membership for a tech is $75.00 per year and a shop 3 techs or more is $250.00...there are benefits to membership. Thanks for watching. If you have not already subscribed to our tstseminars RU-vid channel please do so. Interested in more training? Go to www.tstseminars.org and view full length videos for members on TechFlix for $9.99 unlimited viewing and www.attstraining.com for hands on training and webcast
So on a relative compression test if the current spikes were caused by the bending of valves instead of compression, wouldn't it be misleading? Has anybody seem this? Before you take it too seriously I'm not an automotive tech but more of an enthusiast of things obd2 and modern techniques in general You could even take it as a kind of dark humour. OK so I sat here for a minute and theorized that the difference would be far steeper slopes on the bending valve scenario. Of course the assumption here is that we're all totally deaf and have to rely completely on our instruments.
The only time a relative compression test let me down it's when a timing chain was stretched and the compression looked completely even. Bent valves will be very apparent but old school compression test shows, just takes allot longer because I can do a relative compression test in one minute without opening the hood.
Pete, great job. You crushed it even when you were clearly sick. I just add a thought to 58:46. Your original question was using a RC test with ignition synch. At least that is what I interpreted. The attendee that answered added the pressure transducer to the mix. Now, from an RC test with ignition sync you see the spark to advanced in relation to the cylinder peak of the RC; and the crank reference had moved, I believe that there would be a correlation fault. The cylinder I'd had spun in relation to the camshaft. Unless it was an older system that used the ring gear teeth for RPM and a harmonic balancer mounted cylinder ID for ignition timing. Either way ;now that I look at it, there would be a correlation fault. The RC wouldn't present a mechanical fault because that relationship is still correct. A follow up with an in cylinder test would show proper pressure and waveform characteristics. Then, one would have to ask the question and start looking at the Crank trigger. But, faults would most likely be set. Excellent presentation, I am really enjoying going back and watching the archives. It is inspiring me. Thanks. Eric Scharping
The fuel pump ripple signature is too tricky to be reliable, in my opinion. A new pump looks like hell because the brushes haven't "worn in". I learned from that test that the has to be lots of other supporting evidence for condemning the fuel pump. That visual is just the "icing" on the cupcake. My opinion.
Eric the signature is not tricky if you are using the same scope and clamp. Once you build a library then you can compare the difference from a good pump to a bad one. I do AGREE with you that a new pump may look like hell due to a break in period, but overall it is a helpful test to use. If you baseline vehicles that are new or have no driveability issues, save the waveform and compare it to a problem vehicle and look at the difference. Its also important to look at the top peak of the waveform and note the max amperage. I also use a fuel flow and pressure gauge to make sure the pump is putting out good readings before I condemn a fuel pump for a waveform difference. Hope your enjoying your sunny CA weather my friend...Merry Christmas to you and your family....If you have not already Subscribed to our tstseminars RU-vid channel please do so. Interested in more training? Go to www.tstseminars.org and www.attstraining.com
@@TSTseminars Fair point. I have to agree that it may add an additional test value during the diagnostics.. It wouldn't be a test on my short list but, it may be included in my second or third pass of a drivability diag. I think that I just reacted to that because I have seen too many misdiagnosed pumps;where this test was the primary if not the only value provided as supporting test result. But almost any test can fall into that camp, rihgt!? Ok, good job keeping all of the tests relevant.
