If you log balance rates, and unplug a single injector, I'm ASSuming it would show instantly. Or check rates, shut off vehicle, unplug injector, restart vehicle, check balance rates, repeat.
LLY: EFILive DVT's...broken...?
- Thread starter duratothemax
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If you log balance rates, and unplug a single injector, I'm ASSuming it would show instantly. Or check rates, shut off vehicle, unplug injector, restart vehicle, check balance rates, repeat.
The problem with unplugging one injector connector is that the ECM will immediately sense the open circuit and put the engine in limp-mode. The limp-mode that is associated with an open injector circuit shuts down the affected injector control bus, so you're left with an engine that is only running on 4 cylinders. The injectors are fed constant power, and the ECM (LBZ/LMM) or FICM (LB7/LLY) switches the ground wire going to the injectors to actuate them. There are two injector + power supply busses, A and B, with each bus supplying constant power to 4 injectors. So if there is a short/open-circuit somewhere in the injector wiring, its physically impossible for the ECM to isolate and disable that ONE injector, so it has to shut down the whole bus.
So its basically impossible to narrow it down that way (by unplugging one injector)...
So its basically impossible to narrow it down that way (by unplugging one injector)...
Now that you write that i remember you (or someone else) stating that previously 
. That being said, what would you see as the easiest way to map it. My beater should be up and running in the next day or two, so I can "play" with my DMAX if needed to help with this.
PS. What does that DIC read in your avatar (too small to read it...)
. That being said, what would you see as the easiest way to map it. My beater should be up and running in the next day or two, so I can "play" with my DMAX if needed to help with this.PS. What does that DIC read in your avatar (too small to read it...)
What about a noid light kit(injector test lights) not sure they they would handle 48volts though if it's on your 05, maybe rent a set from Autozone or O'reily
That's a good idea, anyone know if the kit from Harbor Freight has one that will fit with a duramax injector connector?
http://www.harborfreight.com/11-piece-noid-light-and-iac-tester-set-97959.html
The 48V could be an issue too since most gas motors use alot less voltage to fire the injector.
But again...even with that kit...I think you have to unplug the connector and plug it into the noid light. You cant unplug a duramax injector without the ECM knowing and going into limp mode
Shoot, didn't know that.
So it sounds like the best way would probably be some sort of clamp on ammeter provided it fires long enough to register on the meter.
You might even need an oscilloscope to do this, I have no idea.
Fingers would definitely know...
Fingers would definitely know...
I have a oscilloscope just no time to deal with it at the moment, your still going to have to feed paperclips through the back of the connectors so they are not unplugged so you have something to hook the test leads to, might still be able to smoke autozones noid lights for them that way :angel:
I don't think you need an ocilloscope if you're keeping continuity between the connectors/injectors. The event is quick, but even a few milliseconds should be enough to see a flash on a test light. I should be able to rig up a custom noid light, but now I'll need to find a light capable of 48V DC though. Just thinking out loud, I could probably string a bunch of LEDs together to get 48V pretty easily and they would barely take any power to light......I could also use a large resistor w/single LED, but that may affect the injector firing......I may need to experiment with what works. It would also be nice if I could also find part of an old injector harness connector as well (like when you do the #2, #7 fix) to make the tester with.
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What about the injector pulse width?
What's the typical timing for that (in ms) at idle?
I thought it was around 3-4 ms.
I wonder if the numbering is the same between the Delphi and Bosch ecms? If I can get at mine easily without pulling shit off I could test a LMM and a LB7 with a scope. I will see if I can find a decent pinout for the engine connectors so I don't have to go digging to get at all the injector harnesses.
If you have access to a TECH II and are willing to test, send me a PM detailing what vehicle you have to test on and I'll send you the test list.
Our next public release is scheduled for this week, so we won't be in a position to analyse data until after the release is bedded down.
Cheers
Cindy
Our next public release is scheduled for this week, so we won't be in a position to analyse data until after the release is bedded down.
Cheers
Cindy
Um ya it would Ben.
My Labonte W/M measured PW by tapping into the inj. harness power for one injector and used that PW to control W/M injection. If you were to shut off that injector with EFI, it would read zero PW on the Labonte display.
This essentially is what we are looking to check no? Which hole shuts down when selected? Determining if it's firing order or physical location that is shuting down right?
My Labonte W/M measured PW by tapping into the inj. harness power for one injector and used that PW to control W/M injection. If you were to shut off that injector with EFI, it would read zero PW on the Labonte display.
This essentially is what we are looking to check no? Which hole shuts down when selected? Determining if it's firing order or physical location that is shuting down right?
I'm thinking that if these events are below 1ms (looks like on EFI typical pulse width is around 0.3-0.4ms) it may be hard to see a noid light flashing that fast although it may still be possible (you can see down to 5ms okay, but not sure as time values drop to 1/3ms flashes at idle). Using an oscilloscope would certainly be easier because you can set it for different sampling rates and it would seem pretty easy to modify an old injector connector pigtail and to add pins which allow a straight through connection while still being able to clamp onto the pigtail and monitor the injection event. I know there are also automotive DMM's that have the ability to test transient voltage pulses down in the 1ms range so that might work as well......unfortunately, I just don't have one of those yet. If you have the time to try it with the scope that would be awesome and I will try to verify the results on mine as well.
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