Using techron is different than having your injectors professionally cleaned. I just used cruzinperformance. He tested them for flow pattern, flow rate, etc.. They are then cleaned, and "backflowed" on an ANSU cleaning machine. Finally new filters, and o-rings are put onto them. Once the cleaning is done they test them for spray pattern and flow rate again. 16$ per injector plus shipping.
The different tests performed-
Injector resistance
Leak down
Spray pattern
0 second pulsed flow(mL)
100mL pulsed volume
0 second static flow
100mL static flow(mL)
Much better idea then spending almost 100$ a piece for new injectors. My car has 140k miles and I always run a good brand of gasoline at 91 or 93 octane(US octane rating) and my injectors were in really good shape when he first tested them. Cleaning them did make a difference, the flow rates went up, but mine were still spraying in a good pattern. They probably didn't need to be cleaned, but with 140k miles on them there is no way to really tell without pulling them and testing them.
As for injectors needing the vacuum line. Like most things in the fuel system it is run off of pressure. The vacuum lines are what help the injector spray the fuel |