3.0TDI Proper Injector Test

[zafirovp]

Hello,

Can somebody explain me the proper way of testing injectors?

I know the basics but whats the difference between channels 13-14 and 72-75?
Which channel is more reliable?
What are the values for 300, 600 and 1000 bars?
What is the suggested engine temperature for running injector test?

Every info is going to be very helpful since there is differen information on the net about what is good/bad test result.

Thanks in advance.

[gupsterg]

In this post you will see 2 VAG TSB / TPI, both using the differing MVBs.

AFAIK MVB 13 and 14 is showing you injection quantity variation [mg/stroke]. As the MVB label is "Smooth running control" I would assume the variation is to maintain smooth engine running.

AFAIK MVB 72 to 77 is showing you how each injector is being calibrated by ECU.

Activation time 1st calibration pressure (300 bar) [ms]
Activation time 2nd calibration pressure (600 bar) [ms]
Activation time 3rd calibration pressure (1000 bar) [ms]

Read the measured value blocks 72 - 77.

3 values per measured value block appear there (for 300 bar, 600 bar, 1000 bar).

Should the values be higher than minus -45 ms (example - 60ms) or on digit 2 be higher than minus -15 ms (e.g. 20ms), the needle attachment is worn and the injector is incorrect. To avoid repeat repairs, replace all 6 injectors.

>>>> Observe the algebraic sign (minus) in measured value block 72-77 !!!!! <<<<<

i) None of your injectors are going above -45ms ...

ii) Only two on digit 2 are higher than minus -15 ms (e.g. 20ms)

From above what I understand is the negative value is trying to decrease fueling as wear has cause injector to leak excess fuel.

As to idle temp one of the TPI linked above where MVB 13 & 14 is used the suggestion is from cold engine. I would assume the temperature for testing may depend on type of fault injectors exhibiting.

Bare in mind I'm not a mechanic, only sharing what I have picked up due my exploits with the 3.0 V6 TDi.