siemens piezo unit injectors

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eldog79
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siemens piezo unit injectors

Post by eldog79 »

hi, i am looking for some advice how to check a waveform on a 2007 vw piezo unit injector with the pico scope.
i have a 2007 seat ibiza smoking a bit at idle and fault codes for an injector.
any help on this matter would be greatly appreciated
cheers

victor2k
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Re: siemens piezo unit injectors

Post by victor2k »

Hello,
I think only using a clampmeter and a piezoelectric accelerometer connected to the supply of injector you can see the delay of opening moments with a scope,but you must spend some time with setup and positon of sensor for this.
I will attch a file for this(image was captured on LC120 with a knocking injectors in march-april 2015 by me and uploaded on other forum.the orig capture was lost).
Regards
Attachments
injector opening noise.png

steevegt
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Re: siemens piezo unit injectors

Post by steevegt »

Hi

I have used before, and documented in a topic here, one type of clamp, that may help evaluate common rail injectors:
topic14421.html

You cold also use return pressure pulses analysis:
topic10111.html

eldog79
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Re: siemens piezo unit injectors

Post by eldog79 »

thanks for the info,but at present only being able to measure current and voltage.sounds like will have to invest in more equipment to test.

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STC
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Re: siemens piezo unit injectors

Post by STC »

Hi Eldog
smoking a bit at idle and fault codes for an injector
If you are getting "injector Codes" then it will quite likely be an Electrical Issue. The injector looms fail for fun on these.
As for testing these for resistance across, and the Piezo stack shorting to ground then you will need an insulation tester to fire 100 - 150v into them, something like the Bosch FSA050, a Megger equivalent or similar ......

Diagnostic Values are available in Serial Data for these injectors. Have a look at Torsion values too.

Edit : Not sure how you would use a Piezo Clamp on a VAG Unit Injector(PD). This is not Common Rail ?
Last edited by STC on Sun Nov 06, 2016 10:14 pm, edited 2 times in total.

victor2k
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Re: siemens piezo unit injectors

Post by victor2k »

eldog79 wrote:thanks for the info,but at present only being able to measure current and voltage.sounds like will have to invest in more equipment to test.
Hello,
Sorry but you can must see a delayed opening of injector's nozzle vs current command for white smoke(you didn't tell us what smoke ...) :?
But you must use a piezo IEPE accelerometer(with bandwidth 10000 Hz) for this ,not the regular accelerometer from NHV Kit(with bandwidth 0-350 Hz at 3dB).Ofcourse this is valid only for CR not for PD.
On PD system I think you must use the cylinder pressure waveform at idle for diagnose and clamp connected on the left side of engine at the round connector of injectors.
Regards
Last edited by victor2k on Mon Nov 07, 2016 6:57 am, edited 3 times in total.

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