[FIXED] Gas Direct Injection

Tyler wrote:

skip wrote: 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.

Wow, didn't think of that. :ohmy: I'm gonna try to find a diagram of this tomorrow.

Maybe it's all related to the protection strategy? If it detects a misfire, it kills the power to both the coil and injector at the same time.

I'm sure it's part of the protection strategy. Maybe if you lost an injector with 3,000 lbs of pressure behind it we should shut down the spark so we don't burn it to the ground? Who knows.

Yesterday I watched the misfire counters and found some really strange stuff going on. I only have to drive it a couple miles now to get it to act up so that's a good thing I guess. But here's what it was doing.
It was dropping cyl. 2 and 4 under light load and the chk engine light was not on. It was doing eco stops while it while it had a check engine light on for misfires. Don't know how many of you work with eco stop start stuff but that system has all kind of checks it makes before allowing it. I would think multiple catalyst damaging misfires would inhibit this.

So the answer to someones question about the misfire counters is that it picks on cyl 2 and 4 before the light and usually a p0304 gets set. So I think it might need a flywheel. Or at least the crank sensor signal looked at more closely. Maybe I will compare the strength of the signal to another vehicle. I'm kind of thinking it might be dropping cyliner 2 and thinking its dropping cyl 4 / then shutting down #4 in error making for 2 dead holes?? Good times.

Surprisingly, Mitchell had a diagram for this. :lol: It shows all coils getting fed from one fuse... If you're losing a coil power feed, then I'd say that's not just a symptom of the problem.

Alldata had had no diagram for this system (less surprising). The Mitchell program I've been using lately is only good up to 2014-ish vehicles, so no dice there either...
Are you saying the power feed is shared external to the pcm like a traditional MPFI system?

Yep! That's what it showed, anyway. I feel like Mitchell diagrams are not to be trusted on vehicles this new...

Hey sorry I forgot about this thread and never came back to update after the fix.

first I mispoke when I said that the power feed was being taken away from the ign. coils. And also one of you mentioned the schematic showed the power feed for the ign. coils coming off a fuse and whoever said that was also correct and what I meant to or should have said is that that fuse was fed from the same bus bar internal to the underhood fuse box. So sharing the power feed still.

After chasing my tail for a long time I found out that the service information was wrong in regards to cylinder #'s. My service information showed 1 2 3 down the right bank and 4 5 6 down the left bank. in reality it is numbered as odd #s down the right bank and 2 4 6 all on the left bank. So looking for an intermittent misfire that eventually caused the ECM to shut down the cylinder was harder when I wasn't looking at the correct cylinders. With the correct info and all the misfires on the same bank now the problem made more sense.

The last guy to open this engine up had the exhaust cam on the left bank 1 tooth too far advanced. I have no idea why this engine didn't throw a cam timing fault but it didn't. I would have described the idle before the repair as harsh or rougher than normal maybe.

Then I had to drive it for a few days and I was less than nice to it. No faults and runs great.

Success!
Thanks for getting back to us on this one.
Having the cylinder lay out incorrect in the service info sure didn't help.
It makes a lot more sense with all the misfires in the same bank.
Great job! I'm sure she deserved a vigorous test drive

On a side note, this poor thing is only a year old and has already had the timing chain off?
Sounds like maybe you're not the only one who has been less than nice to this one, lol.

Thanks for the update! I was ready to hear about some wiring strangeness or whatnot. :silly:

Just curious, once you got the correct cylinder layout, how'd you get down to a timing issue? :huh: Not sure if all the cams are monitored on this engine or not. Wondering if this would have shown up on a relative compression or vacuum transducer test, now knowing what the issue was.

Tyler wrote: Thanks for the update! I was ready to hear about some wiring strangeness or whatnot. :silly:

Just curious, once you got the correct cylinder layout, how'd you get down to a timing issue? :huh: Not sure if all the cams are monitored on this engine or not. Wondering if this would have shown up on a relative compression or vacuum transducer test, now knowing what the issue was.

Mostly the idle quality and knowing someone else had been in it. Engineering assured me they have seen cam timing out without a cam timing fault stored.

Yes all 4 cams are monitored. These things are known to store cam timing faults when oil gets thick. Like sub zero temps. so I'm still amazed.

skip wrote: Engineering assured me they have seen cam timing out without a cam timing fault stored.

Nice. :lol: Seems like weak code set criteria, then. Anyway, nice job on not giving up!