Frank Massey's Top Ten Tests with PicoScope: #7 Common rail pressure sensor testing

In Frank's seventh video, he looks at the performance of the high-pressure pump under full load.
Frank discusses the theory of the test, what is being tested and the use of PicoScope software in detail. He covers timebases, current and voltage ranges, channel options, and scaling.

[@gerrykapogiannatos1139]

Thank you for this insight presentation on common rail diagnostics. Another great Frank Massey video.

[@pedrolriveranegron5178]

Excellent Diagnosis! Greetings from Puerto Rico never miss any of your videos. Thanks for teaching us on how to use an oscilloscope!

[@ingejeppesen1358]

Great test. High value in the field of our trade.

[@ThunderbirdRocket]

Tremendously helpful ! Thanks !! You are are a great coach !!!

[@MaicSalazarDiagnostics]

This is a great video! Thanks

[@kevinedward1234]

Frank, great video!!!!

[@nigelclark7360]

Excellent video

[@kasapis6]

Great info thanks

[@train4905]

Absolutely superb.

[@mikem1014]

Frank You Are Amazing...

[@DanWallis86]

This might be a dumb question but when you say decay time is that referring to how quickly the pressure dissipates?

[@BenJamminJones1]

Hi Frank - great video! Regarding the test to close the DRV and to check that system pressure is being maintained, is it possible to do this on a 3.0 tdi (V6) where you have two banks of 3 cylinders and 2 high pressure fuel rails, i.e. 2 DRVs, one on each rail...

[@user-pw8yu7nd7p]

THANK YOU VERY GOOD VIDEO

[@BenJamminJones1]

Hi Frank, I own an Audi SQ5, 3.0 tdi V6. They have a Bosch CP4 HPFP. These are know to fail and apparently they can just die without any prior warning. The pumps chew themselves apart and tiny metal particles then contaminate the fuel system and piezo injectors, leaving a VERY large bill for the owner. Can we use your test here to check and prove that the Bosch CP4 pump is working efficiently? These pumps are apparently ticking time bombs so it would be good to see any wear on the pump before it innevitable fails?

[@jacktingzon1012]

Hi frank, i tried this method on a 2008 hyundai tucson crdi. It's running fine i was just inspired by your method and tried it. I ground the negative side of the rail pressure regulator while idling, it stalled as expecred and got a nice pressure ramp up to 4.5V on the pico but when the signal reached 4.6V the ramp starts to slowly slope down. The whole max pressure only last 600ms. The pressure decays up to 0.5V in around 5 secs. I wonder how the fuel was dump that fast.

[@mattd2528]

Jack Tingzon I have the exact same outcome when I did this test in two different Mercedes sprinters, also interested in knowning why that might be happening, I’m pretty sure the sprinter system is identical to this Audi edc ecu Bosch common rail,

[@miclewis55]

Pure gold … thanks !

[@parsonsmechanical]

Hi Frank, i have a 2015 land rover disco 4 306dt. it has long crank times (no fault codes). it cranks for a long time with out creating pressure. (low side pressure is good). when the pressure does start to increase its rise time on the first test of this video is 896ms and on the loaded / second test is 646ms. would this indicate a faulty high pressure fuel pump? could you recommend any further tests to confirm or rule out other causes? Many thank, Cail

[@jwoeltje6949]

Will this Procedure work on the OM642 sprinter?

[@tomvleeuwen]

Apparently, when running the engine at 2000 rpm and keeping the DRV closed, you will exceed the maximum pressure of the sensor. As you say at 20:50, the maximum system pressure is 1650 bar, but there might even be 2000 bar in the rail (due to the sensor clipping). Due to this clipping, you cannot see if there is a decline from 2000 bar to 1650 bar. Basically, you are blind for any slow changes. If you run the engine at a lower RPM, say 1500 rpm or even idle, could it stall before it reaches the maximum pressure of the sensor so that you can observe a possible slow decline in pressure? Or does the engine just keep running until the sensor starts to clip?

[@4X1000]

One h*ll of an interesting question Tom! It would mean that if there where a light decay it would not show up during enough hold time of the DRV. Of course, the ECU might shut of the injectors before the RPS reaches its maximum output voltage. Who knows...

[@jurijpodolinsky2572]

good about the pressure test, but sometimes pressure test is good, 1000 rpm on test bench is ok, 2000 rpm fail an fuel volume, but on the car we do replace injectors and pressure regulators first, but nothing happens before you will change the fuel pump.

[@trainer2018]

Is this Diesel or Gas. He said common rail so I'm thinking Diesel.

[@armandonika]

Diesel he is located in england.

[@BenJamminJones1]

Bosch common rail is alway Diesel 🙂@@armandonika