Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I am working on a vehicle with Bosch Direct Gas Injection. The manufacturer I work for doesn't think I need to know whats inside The ECM as far as drivers for the injectors and cols. I'm hoping someone ( Paul ) might have a schematic for this system that has the internal stuff.
Here's what I got.
This is a 2016 vehicle with a V6 supercharged engine. After the vehicle is fully warmed up cyl. #4 will get shut down. Still not sure if the ECM shuts off the injector and the coil because its protecting itself from an over current condition, or just because it doesn't like what it sees from the crank sensor. But it is starting to look like something in the circuit is destroying drivers in the ECM.
Lots of weird stuff going on but after comparing some of my readings to a known good vehicle most of the things I have seen so far I can tell you are normal. For example the injector circuit only charges the capacitors needed to make the boosted voltage on 4 of the 6 cylinders. I chased that for a while because it just so happens to be one of the cylinders is collecting all the misfire codes. So I chased that issue right down the old rabbit hole till I figured out that's normal.
I have watched my crank sensor while overlaid with my #4 injector circuit and my ign coil circuit but never really saw any kind of break up in the crank sensor signal.
I was told to replace the fuel injectors on that left bank as we do see a lot of injector issues. I was unable to duplicate the misfire after replacing those 3 injectors but really I'm not all that optimistic that the vehicle is fixed. This vehicle has already got past some of the best minds in the industry and has been bought back from the original owner.
Hey skip! For our info, what make/model on this 2016?
This is a 2016 vehicle with a V6 supercharged engine. After the vehicle is fully warmed up cyl. #4 will get shut down. Still not sure if the ECM shuts off the injector and the coil because its protecting itself from an over current condition, or just because it doesn't like what it sees from the crank sensor. But it is starting to look like something in the circuit is destroying drivers in the ECM.
'
Just to be clear, this thing has had multiple ECM's due to driver failure? Or, are the drivers just getting shut off in response to a misfire?
The same thought here could be shutting off the cylinder to protect the cat, I would look for misfire codes before it shuts down injection, and ignition.
The issue could be as simple as spark plug failure
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
well, I don't have a current probe so I'm just watching voltage while I wait for it to act up. I'm watching the control side of the Injector. But the feed side is a little strange because of what I believe is charging a set of a boost capacitors.
well I guess it could still be a spark plug. especially since I seem to be able to duplicate it at idle. But those have been replaced according to all the history I've been able to see. So I would have to believe that one plug was replaced with another bad plug. Sounds like another rabbit hole.
ya its kind of crazy but it does look like modules fail on this fine truck. The history shows that it got one within the last 1200 miles. The thing has 4200 miles on it now.I do think the ecm is shutting itself down to protect the catalyst but I feel like it either thinks its missing due to some breakdown in crank sensor signal or it's getting blasted electrically by the circuit. For the longest time I could bring back that cylinder with a key cycle, then that ecm wold not come back with a key cycle and I pulled one out of a stock unit(plug and play after security relearn) and the cylinder came back right away, but 5 miles into a test drive it started dropping the cylinder again. Actually had misfire codes down the hole bank but the counters all landed on #4. Strange stuff like that makes me think its more like a signal falling off or a ground for that left bank is less than great.
Can you scope the secondary ignition to verify miss is taking place on cylinder 4?maybe misfire moniter is miss identifying the cylinder? I would be interested in a look at the tone ring for the crank sensor maybe it's damaged? To you have a crank signal capture you could post?
Ben wrote: Can you scope the secondary ignition to verify miss is taking place on cylinder 4?maybe misfire moniter is miss identifying the cylinder? I would be interested in a look at the tone ring for the crank sensor maybe it's damaged? To you have a crank signal capture you could post?
Sent from my SM-N920P using Tapatalk
Funny cause that's the first think I looked at. I had the crank sensor out and looked at it pretty close while I rotated thru the whole flywheel a few times. I'm going to pay close attention to the misfire counters just before it shuts down #4. Thing is i never really feel any kind of misfire before it becomes a dead hole. And then the battery feed for the ign coil is gone and the pos. side of the injector is shut off also.
skip wrote: ya its kind of crazy but it does look like modules fail on this fine truck. The history shows that it got one within the last 1200 miles. The thing has 4200 miles on it now.I do think the ecm is shutting itself down to protect the catalyst but I feel like it either thinks its missing due to some breakdown in crank sensor signal or it's getting blasted electrically by the circuit. For the longest time I could bring back that cylinder with a key cycle, then that ecm wold not come back with a key cycle and I pulled one out of a stock unit(plug and play after security relearn) and the cylinder came back right away, but 5 miles into a test drive it started dropping the cylinder again. Actually had misfire codes down the hole bank but the counters all landed on #4. Strange stuff like that makes me think its more like a signal falling off or a ground for that left bank is less than great.
This is the line of thought I've been following. I'm thinking of the GM Lambda platforms with the DI 3.6L that have ignition coils shorting secondary voltage to the ECM driver. The driver ends up sticking on, cooking the coil AND the ECM. The symptoms don't match exactly, but it sure sounds like something is (eventually) taking out the ECM driver. It's a long shot, but maybe try moving the ignition coil from #4 onto a cylinder on the other bank?
I also kinda like where Ben was going with a misidentified cylinder. Maybe try pulling a coil on another cylinder to make sure the monitor is accurate?
And then the battery feed for the ign coil is gone and the pos. side of the injector is shut off also.
Wow, the ignition coil battery feed can be controlled independent of other cylinders? :huh:
What I'll do is take a photo of a Bosch injector waveform out of my Bosch training book tomorrow. What I remember is you have to watch both control and feed side on these injectors
And then the battery feed for the ign coil is gone and the pos. side of the injector is shut off also.
Wow, the ignition coil battery feed can be controlled independent of other cylinders? :huh:
Wow! what could be the benefit of shutting down the coil on a missing cylinder?
I think it's actually a sign that coils share a power feed with the fuel injector. Which brings a bunch more stuff into play. The engine harness has been replaced ced supposedly but the system has a capacitor on the coils ign feed circuits. I bet that thing is original. I would post my schematic of it but can't copy it for some reason.
Sent from my SM-N920P using Tapatalk
Hmm I've never seen a capacitor get hot and shut down but then come back to life but I haven't seen everything so sure could be worth looking into is there 1 for each cylinder? Or 1 capacitor shared for all 6?
Eurotecknic55 wrote: What I'll do is take a photo of a Bosch injector waveform out of my Bosch training book tomorrow. What I remember is you have to watch both control and feed side on these injectors
That would be great. I'm really interested in what the drivers and circuit looks like inside the ECM. My schematic shows nothing, just empty box.
I did watch both sides but the feed side would normally look like a flat line. But on this circuit you see some pulse width modulated pulses I think are charging capacitors. Or what my circuit description calls a "2 stage driver"
Topic Author
