Hello!
I have new injectors from aliexpress 800cc/min side feed for subaru (yellow) 16600-AA170 and have no more data.
I think to assembly these to fuel rail and do measurement. But with Output test I don’t have precision opening times to make measurements in which time thay opens and inject some fuel out (fuel rail is outside engine).
Is it good measurement to set opening time from 0,4 ms and add 0,1 until fuel goes out? And when fuel starts going out by for example 0,9ms than approximate injector opening time is 0,8ms. All measurements with 13,8 volt stabisiled supply connected to baterry and 43 psi fuel press.
If this method is correct, it would be very good if the ECUMaster added this option in the software.
It is better to inject for example 100 times 2ms and 100 times 4ms. Then based on injected volume you can easily calculatee the dead time. It takes into consideration both opening and closing time.
Other method is current probe.
Monitoring current with the scope when injector opens, you can spot easily the point when the needle starts to move.
2 Likes
It’s also possible to get extremely close dead time data with a knock sensor pressed against the injector body and an oscilloscope hooked to injector output and knock sensor. This won’t tell you about fuel flow, though.
See this video from Shane Tecklenburg. I used ID1300 injectors and entered exactly the data published from their website. This had 1.035ms at 14v 3Bar pressure. I noticed fluctuations with O2 when my headlights turned on. After going through Shane’s method, I measured 0.60ms dead time at 14v 3Bar. Way, way off! It was hard to believe, but now I don’t care what data I find even from ID. I’ll be testing from now on. Backed up my results with batch injection vs sequential for both dead time data and found that my dead time with Shane’s directions gave very close real dead time values.
6 Likes
Very nice methode. Gone try it out as well !!
I tried out measuring the injector delay with a scope and a knock sensor and it worked perfectly!
On further thought, I’m unsure if this value changes under pressure. I measured the dead time the same way that the linked video showed, IE in free air with no pressure on the injector.
I’m thinking about building a single injector holder to test this again under pressure. If it changes significantly that means it is required to measure this under pressure. In either case I’m pretty confident that the knock sensor is an acceptable method to detect when the injector is fully open. Just a question of if it changes under pressure enough to matter.
Yes, times change with total system pressure, voltage and differential pressure across the injector. Meaning manifold pressure also changes how an injector can open and close.
Then yiu have linerization to account for.
Interesting, that makes sense to me. The issue is that the EMU Black only has one table for injector dead time. Is it just assuming a constant dead time?
Is it known what pressure the injector cal table is assumed to be measured at?
I am building a rig to measure this under pressure, right now I’m assuming 43.5psi is the right value. That’s a total guess though.