OMVL LPG gas injector lifetime

Question

My vehicle has LPG as alternative fuel. It have OMVL REG injectors without temp sensors.

It has already ~ 60000 km (In picture you can see, that one injector not used; 3 from left). Check engine light start coming on, and i cannot anymore adjust calibration for LPG and i bought new LPG injectors. After that i disassemble old one. In picture no 1, injector with number 3 was not used. Only moving part of injector are in my fingers in picture no 2. It one side is spring and another side is rubber. In picture no 4 it is just electromagnet.

So, in picture 1, all rubbers looks identical in its thickness (injector no 3 not used at all). What part can be run out in this setup ? Electromagnet? That part witch is in my fingers in picture no 2?

Pic no 1.

Pic no 2.
Pic no 3.
Pic no 4.

Answer 1

The springs seem to lose their springiness. This means the valves (the bits in your fingers in picture 2) do not return to seal off the injectors quickly enough, so too much fuel enters the cylinder. The engine detects a mixture problem and tries to compensate, but (unsurprisingly) can't get it right.

The other part that wears out is the very small o-ring that sits between the spring and the outer cylinder. It normally stops the valve from banging into the outer cylinder when it is opened. As the rubber ages, the valves start to "clatter" as they hit the cylinder. I haven't had this problem, but I understand it can also cause mixture problems.

Answer 2

Can you use a multimeter to measure the resistance of the solenoid coil in the injector? If so, then make a comparison with the new ones.

Seems to me that the injector would fail either by leaking or not opening. An open circuit in the solenoid's winding would cause the latter problem, and is probably difficult to repair (likely potted in epoxy).