The engine sounds off when the O2 sensor is lean, but I can't say for sure that it sounds like a misfire.
I should've taken a pic of the head when I had it off the cylinder, but I doubt there's a lot of squish. The compression ratio is 8.5, which is quite low for an engine this small so I...
I was trying to see if there's a way to figure out whether or not the problem can be attributed to misfiring other than just putting on a new crank sensor and coil. If it is indeed a misfire problem then advancing spark / longer spark duration / things to promote faster burn rate at the same...
I switched over from crank timed to cam timed injection (from 1 injection per revolution to 1 injection per 2 revolutions) and the problem still persists.
Hello,
I am converting a ~300cc single cylinder air-cooled engine to EFI. When running at around 3000RPM with a light load on it, the leanest the engine will sustain a stable air fuel ratio is around 13.5 +-0.5 variation. If I reduce the fueling even just slightly (a few percent less), the AFR...
Well the leakage rate must be small enough where the engine can sit there for a year or longer without the engine being flooded with fuel. My car was running a bit rough at low speeds and it was time for the routine checkup anyway. I don't know how they diagnose it was a leaky injector but...
That explains it. How often do fuel injectors leak? It seems like it would be difficult to achieve an absolute leak-free seal with metal-to-metal unless there was some sort of significant deformation like in pipe threads and compression fittings. Is there some sort of mechanism that prevents...
That makes sense - thanks for the explanation. What I don't understand then is why it costs me $120 to replace a fuel injector when I can't spot anything else in the design that would make it expensive. I assumed that the ball and seat were the most costly components but if it can be made for...
In looking at some designs, the ball is attached to a stem, which is a lot more expensive than just having a precision bearing type ball. I really don't see how having a polymer seat would be more expensive than a metal one. You should be able to machine a polymer seat using the same process as...
One of the fuel injectors in my car developed a leak on the inside valve. This got me thinking - why is the needle seal metal-to-metal? With the different types of fuel resistant polymers and elastomers out there today (ex. PTFE, PFA, Delrin, Viton rubber) , wouldn't it be more reliable and less...
Is it possible to get a rough idea of position or velocity without some type of position sensor from a solenoid actuator? I am thinking that solenoid actuators are usually designed so that the inductance of the solenoid increases as the armature moves when the solenoid is turned on. Could this...
Well, not really.
According to Goodman and Soderberg, when calculating fatigue life, one should take into consideration mean stress and stress amplitude. For example, in the extreme case where the mean stress is almost equal to yield and the amplitude is zero, you just have static loading and...
I haven't discussed it with any spring manufacturers because it's not a helical spring. It's just a diaphragm made of full hard temper stainless steel, which acts as a spring.
I think I got it though. Let me know if this makes sense. See the attached drawing. So after I preload the spring, it...
We are planning to preload a spring past its yield strength, but before its ultimate tensile strength. The spring will then be used in service for 10^7 cycles, but with a small amplitude. The amplitude stress is about 30% of its endurance strength. Even though the spring has a permanent...
It's the check valves that prevent back flow. Pumps that you buy have valves installed. Since we are making our own pumps, we need to design the check valves.
