Author Topic: Ideas for how to pop test 2-stage 1.9 injectors (Read 5097 times)

molgrips · « **on:** November 11, 2008, 10:55:44 am »

Now I haven't actually tried this, or even taken the injectors apart, just looked at the diagrams on Vince Waldon's site. But it seems to me that you could test the lower pressure as normal, and to test the higher pressure you could reassemble it without the lighter spring, measure that pressure, and then add the two to get the actual higher opening pressure.

Another possible idea would be (assuming they were properly calibrated to begin with) to measure the height of each half with a micrometer, then measure them again when you've lapped the halves and reduce the shim sizes accordingly.

Then again, another thought occurs - why do you have to lap them in the first place? What changes when you undo it and reassemble it? If it doesn't leak to begin with, why would it when you put it back together?

jimfoo · « **Reply #1 on:** November 11, 2008, 04:55:17 pm »

I never took mine apart, but if they work like the TDI ones, it won't work that way. On them if you took the lighter spring out, you would make no pressure. The second spring comes into play at a certain lift of the needle.

molgrips · « **Reply #2 on:** November 12, 2008, 12:07:41 am »

How about this then.. Measure the shims beforehand, test and calibrate on the first opening pressure then measure the size of the shims when you're done and reduce the size of the secondary spring shims by the same amount?

SR Heer · « **Reply #3 on:** November 12, 2008, 09:05:55 pm »

Giles charges $50 each to refurbish dual stage injectors. I asked him about his new AAZ injector testing machine and here is waht he said:

"our new electronic test box tests the opening pressure while a full
volume of fuel is flowing through the injectors just like at full
load on the car.
normal gauges only test them with very low fuel flow and cannot
check the 2nd high flow opening pressure.
our new equipment also measures the leak back time from top
opening pressure to lower pressure setting.

yes we ultra-sonically clean the AAZ injector nozzles. if they don't
pass a full barage of tests then we scrap that nozzle.

Bosch never sold that nozzle by itself so we can't buy original
nozzles for them.

it is not recomended to replace the nozzle with something different
in the two spring injector
Giles"

molgrips · « **Reply #4 on:** November 13, 2008, 01:43:52 am »