So you got your reports back for your GDI or Piezoelectric fuel injectors back and you don’t understand the reports. No worries, whether it was a BMW N54, N63, N74 or other Gasoline Direct Injector, the basics of the report are the same. They are not hard to understand and we try to make them as “idiot proof” as possible.
Your report will have a big check mark or x in the upper right hand corner. If you can’t follow along with everything else, this alone will tell you if the fuel injector has passed the manufacture’s specified test plans. The rest of the pages are the details.
In the top portion of the results, customer specific information can be found. Things like their name, their customer (order) number. The injector part number. For Piezoelectric BMW N54 N63 or N74, the correction values are also factored in under the “FD”. The Injector’s manufacturing Index is found under the correction values as well. Actuator info is also noted as different injectors are driven in different ways.
What does this all mean?
As we explained in the article written explaining how customers should manage their expectations, not all injectors that get a big red X in the upper right are actually “Bad”. Unlike port injection, GDI injectors aren’t measured in a cc’s/min or lb/hr rating. They do still have specs they must meet. The GDI fuel injector operates in a very dynamic way, however it is still tested at specific operational points. These are called “Test Plans”. They are abbreviated on the plans as (TP1, TP2, TP3 ect.) Each TP lists out the the STROKES, the Pressure at which the test fluid pressure is feeding the injector as well as the opening time your ECU or DME (in the case of a BMW N54) would be sending it.
Test Plan information
Each iVM (individual volumetric measurement) TP (test plan) is measured by mm3/STRK. This is said as cubic millimeters per Stroke.
Each TP has 3 ranges and are detailed via numbers, lines and color for ease of reading.
-Good = Green – Noted as a minimum and maximum number and a solid line on the chart
-Perfect = Blue – dotted lines in the chart
-Out of Range = RED – above or below the solid lines on the chart
The maximum, average and minimum results from the test are noted above the chart. When an injector is as clean as possible, these numbers “should” be all the same.
So are they ok to use?
We aren’t in the opinion business when it comes to this. We are here to clean the injectors and give you the results of the service. The customer can make the decision to either use the injector or replace it.
Lets just say the injectors are from your BMW N54. Your car is a pleasure car making a little more than stock horsepower, not pushing the limits. Your injector “failed” overall and there is a big red X in the upper right corner. All the test plans have passed with the exception of TP5. The minimum number in the Siemens VDO test plan is 19.2 mm3/STRK. Your injector came in at 19.1 mm3/STRK. You might put that injector in the car and NEVER know it “failed”. Put it in your Aunt Sally’s car she drives to Church an the grocery store once a week and I can guarantee you will never know it “failed”.
On the flip side, you are maxing out hoursepower and TP1 at high pressure has a min of 34.3 but your results are showing 22.8 mm3/STRK, you might want to think about using that injector. Losing a high dollar build over a lower flowing injector is a very good posibility.
The decision is yours
You have all the info in these reports to make the best decision for your situation. If you reach out and we link you back to this article, don’t be offended. We are simply telling you it is your choice.