In-cylinder pressure testing for less than $100

[@MarioDallaRiva]

Thanks, Sean. You've raised the bar for teaching this topic! Interesting.

[@VideoDetection]

Very well done comparison of pressure sensors and explanation of absolute versus gauge pressure. Excellent information on calibration for the PicoScope! I've subscribed!

[@nateklein7342]

Great video Sean! BELOW ARE PRICES IN CANADIAN ROUBLES AS OF MAR/2022 Fluke PV350 (old design) - $800-$1300 Ebay/Amazon sensor - $28 Honeywell 300psi (px2an1xx300paaax) - $188 Honeywell 500psi (px2af1xx500paaax) - $160 SSI Technologies (p52-500-a-b-i36-4.50vp) - $205 The clear winner here for me is the SSI Technologies sensor based on it's both its clarity and relative price between both Honeywell sensors and the Fluke PV350 . I believe the SSI Tehcnologies sensor provides the best overall value as I don't have a school budget at my disposal. =] VIDEO IDEA?: Would be great to see a video on the comparison of commonly available 'Low Amp Probes' using the Picoscope, and maybe even comparing some larger scale Amp Probes to re-enforce some of the reasons a '600AMP Clamp' might not cover all of the required uses in the automotive field. And comparison between budget options vs more expensive options.

[@danielthechskid]

The "blue box" is a 10 turn trimmer potentiometer.

[@chriscadman5715]

Excellent comparison test. Thanks!

[@eddiedavis7153]

Thanks for the review will pick up that ssi sensor.

[@drakevelazquez8728]

Stumbled on a gold mine

[@johnmwangi6291]

Thank you sir.. keep them coming we are learning ✍️...

[@davecolston3564]

This is an excellent video. Thank you very much.

[@EATSLEEPFARM]

Really good stuff here. Thanks for the video

[@ovalwingnut]

This is really not your first rodeo. Really impressed with your knowledge you have in this field. GR8T gray matter food Thanks so much. Cheers from So.CA.USA 3rd House On the Right

[@moluaisaac6433]

Very well done. Pls my question is if I don't have vacuum machine how can I use the transducer?

[@eduardotejeda]

Thanks

[@bluedeckelectronics]

Good video ! Thank you !

[@one_mega_ohm9139]

For a running test do you have to disconnect the fuel injector for the cylinder with the transducer in it? Is the secondary ignition wire that's being monitored at 13:10 just going to ground?

[@siuautomotive]

You don’t have to disconnect the injector. Usually the pcm cuts fuel once it detects a misfire anyway. I don’t run the engine for a long period, so it’s really not an issue. Yes, on that secondary, you can just ground it through a test plug. You can also see the ign timing by tapping into the coil signal wire as well.

[@stevestadnik9206]

You should have filtering capacitors on the input and output pins for noise and transients.

[@nigeldoran]

The Amazon and Honeywell sensors are analogue transducers, basically a potentiometer with 5V across it and the output is the slider acting as a potential divider What is being output is the voltage for the wiper location. It is not correct to refer to it as a sample because there is not an analog to digital converter inside the transducer. There is a response time which is the time a change in pressure takes to produce a change in position of the wiper which depends on the magnitude of the pressure change and the inertia of the potentiometer and age/wear. What is not addressed in the transducer specification is this: what is the response time for a given pressure change i.e. if you apply a 20psi pressure step is that 1ms or is it less or is the 1ms for a full scale pressure change i.e. 0psi to 300psi. Inferences can be made from the tests done on the car. Also when using a digital oscilloscope care has to be taken because you can have the quantising levels and sampling frequency of the scope appearing in the measurements. A very helpful video and well explained and put together.

[@jeremybloom8225]

Thank you Sean, what a cool video! Hope to see you at ATRA again this year!

[@frankjohn4302]

Good video thanks

[@alrifainidal]

Well done thanks

[@4YouWHOyou]

Can i use this kind of pressure transducers to measurement vaccum in intake mainfold ?

[@fascistpedant758]

The discrepancy with the expected time between spark and peak compression is about the time for the pressure wave to travel from the cylinder to the transducer at Mach 1.

[@John-rw9bv]

The electronic circuits have quite a bit of delay too, but i suppose Mach 1 is a good point to make

[@lovetolearn5253]

I can't find the P52-500-a-b-I36-4.50vp sensor. Every time I type it in it goes to p51 not p52. Is there a difference between the 2? Any help would be greatly appreciated. I'm trying to build a decent incylinder pressure transducer.

[@siuautomotive]

I think I typed it in wrong. That p51 should be good!

[@lovetolearn5253]

@@siuautomotive 👌 i already ordered it. Your video really helped me alot. I ordered a nice clean adjustable volt regulator for my 5 volt out put. I was very impressed how clean that p51 sensor came out.

[@RadFox1320]

So the real running compression is only about 60PSI on this engine?

[@siuautomotive]

Yes, when an engine is idling and pulling strong vacuum, not much air enters the combustion chamber, so there’s not as much to compress. Cranking vacuum is very low, like 1-3 in hg because the engine is rotating relatively slow. So during cranking, the engine is able to take big draws of air and that allows for a higher compression measurement. If I were to snap throttle with it running, you would see the running compression jump near cranking compression values.

[@Rusefi]

Do you at all mention how is the sensor hooked up to the vehicle mechanically? I assume you did not drill the head.

[@siuautomotive]

I use a compression tester hose and go through the spark plug hole. Make sure you remove the schrader valve in the compression tester hose. Also, make sure you disconnect the coil or ground the plug wire.

[@Rusefi]

@@siuautomotive Oh the cylinder is deactivated :( Gotcha. I am looking to hack into a cylinder while it's alive.

[@siuautomotive]

Ah, the diesel instructor here does that, but he goes through the glow plug hole. He uses a different pressure sensor that’s much more expensive.

[@Rusefi]

@@siuautomotive fun fact: VAG and Opel have cylinder pressure sensors build into some glow plugs! stuff like PSG007

[@John-rw9bv]

​@@Rusefi woooooooooaaaaaaaah, that sensor is only 80€ here in germany. I guess it would work the same way the sensors in this video work, albeit for a running engine. Also if you're from rusefi, thank you for taking an interest in diesel ;-)

[@Z14kt12timandjes1]

I can't figure out what I'm doing wrong, but I'm getting around 34 psi at the top of my waveform (the TDC traces). From the bottom trace to the top, I'm only getting 48.45 total psi. I've double checked I've got my cheap transducer set up like the settings in the video. This is on a 2007 4 cylinder Toyota Camry. Shouldn't my total psi be much more than I'm getting? Thanks for any help.

[@siuautomotive]

I would need more details. What sensor do you have? What scope? Did you set a custom range? What’s the pressure range for the sensor? On my “gauge” 500 psi sensors, 350mv is -15 psi, 500mv is 0 psi, and 4500mv is 500 psi. Where your readings while cranking or running?

[@Z14kt12timandjes1]

​@@siuautomotive Thanks so much for the reply. I have the same cheap 500 ebay transducer that looks like the one in the video. I set up the range as 380mv is -15 psi, 500mv is 0 psi, and 4500mv is 500 psi, and my scope is a Pico 4424. I took the waveform capture running only. Thanks for your video and helping me with this.

[@therealspixycat]

Why is the new pv350 not usable?

[@siuautomotive]

I don’t know what fluke did to the internals, but it doesn’t update the signal fast enough for in cylinder testing

[@rosuiulian4552]

Where did you foud the ssi 300 psi at 125 bucks? I found it at over 200 bucks on various sites

[@siuautomotive]

The ssi was a 500 psi sensor. www.digikey.com/en/products/detail/amphenol-ssi-technologies/P51-500-A-B-I36-4-5OVP-000-000/1665820?s=N4IgTCBcDaIAoFYCMBaBAGdKCCKBCKAkgMwBsKALGgPIBqcIAugL5A

[@frnkjones40]

That looks more like Tallahassee FL. Great vid though.

[@John-rw9bv]

Great video! I learned an awful lot. I was hoping to use in-cylinder pressure to control injection timing in a diesel, but since these use spark plug holes (obviously replacing the sparkplug) i suppose they're not capable of reading pressure in a working cylinder. What techniques/hardware is needed to essentially put the MAP sensor into the cylinder where, haha, it really ought to be :~)

[@cardiaglexia995]

Warum schraubst du nicht einfach die glühkerze raus ? Du bekommst ein tolles bild deiner zylinderarbeit.lg & viel gesundheit für dich & deine familie.

[@John-rw9bv]

@@cardiaglexia995 Sorry i can't speak German, but i translated with deepl. You can replace glowplug with pressure sensor, in fact Kistler sell a glowplug/pressure sensor combo for any diesel. They are very expensive though, and only used in research. Having said that, it is quite surprising all diesels don't have this sensor, as it can detect engine wear before it becomes a problem, and can increase fuel economy (particularly as the car ages). I suppose both of these things are good, not bad, if you are selling cars.

[@cardiaglexia995]

@@John-rw9bv hello and sorry for my wrong language.i only if we screw in the pressure sensor instead of the glow plug , we get the same good values as with the benziner.lg and health. All good for you.

[@ralfsautomotive]

The Fluke is way to dirty of a signal. Definite need to work with Filter. The Pico is a way better sensor.

[@joedejesus5898]

Nice video! whats the lowest psi the SSI 500 psi sensor can measure?

[@JohnathanFx]

Had me till you said in the upper atmosphere we'll float away because no pressure 😒😒🤣🤣🤣🤣

[@happikon]

How to spot pv350 befor buy?

[@siuautomotive]

That’s the crazy thing! I don’t know if you can tell without pulling the cover and looking for that blue box. Honestly, if you have a pico or autel scope, I’d just get the ssi technology sensor

[@happikon]

@@siuautomotive thanks

[@derrickdaly296]

I cannot figure out what year it changed

[@LittleAirplaneDriverandFix-i8i]

I am hearing you run the engine. Is the pressure transducer connected to the spark hole and that cylinder is not firing and the other cylinders are firing?