In-cylinder pressure testing for less than $100

In this video, I compare five transducers to see if they are adequate for in-cylinder pressure testing. I compare all four sensors to a tried and true Fluke PV350. The cheapest is an ebay/amazon sensor ($20), next I test two Honeywell sensors ($65 and $88), and last I test an SSI Technologies sensor ($125). All are available from DigiKey and other retailers.

If you're only interested in the results, here are the timestamps where I show the individual results:
Fluke PV350 (old design) - 15:00
Ebay/Amazon sensor - 25:14
Honeywell 300psi (px2an1xx300paaax) - 30:48
Honeywell 500psi (px2af1xx500paaax) - 36:17
SSI Technologies (p52-500-a-b-i36-4.50vp) - 41:14

I use a Pico Scope to measure in-cylinder pressure along with secondary ignition and intake pulses (from a home-made tool). In this video, I cover the difference between gauge and absolute pressure and I explain how to setup the custom probes for each of the sensors.

During analysis, I cover the speed at which the sensors output information and I also cover the delay from the sensor from when it sees pressure vs. when it outputs its signal.

[rainerrieck]

after six months of searching to learn about sensors and scopes, everything i wanted was explained in a few of your videos and in a very easy and professional manner. thank you. I am doing this just to keep my mind active and sane after retiring

[jondieter]

This is an amazing.video on pressure transducers. It provides so much detail on pressure transducer options and there setup. I ended up getting the SSI pressure transducer. Thank you for putting this video together it has helped me out a lot. Some of.the best training videos.

[nateklein]

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.

[MarioDallaRiva]

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

[MarzNet]

That is very cool. I've been using a 5VDC USB Power source on my custom test equipment. A Custom set of USB to 4mm male banana plug leads does the trick. For 12V, I have a set of spade terminal to 4mm male banana plug leads (fused) and connect to a Milwaukee m12 battery.

[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!

[danielthechskid]

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

[AstonSubstantive]

That was an absolutely fantastic video. Thank you so much for making it.

[das]

@22:08 Basic engineering / tech rule : never use the power off a product you are diagnosing. Keep your diagnostic independent.

[eddiedavis]

Thanks for the review will pick up that ssi sensor.

[johnmwangi]

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

[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.

[davecolston]

This is an excellent video. Thank you very much.

[EATSLEEPFARM]

Really good stuff here. Thanks for the video

[das]

Curious engineer here : These in line pressure sensors, I missed where they attach ? How do you get access to the cylinder head as it runs

[stevestadnik]

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

[moluaisaac]

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

[one_mega_ohm]

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?

[fascistpedant]

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.

[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