Ok, first off, don't shoot me, this isn't a corvette problem. Its a 2010 yukon with a 5.3, and 213K on the clock. Theres a lot of smart guys here that are very knowledgeable and hopefully can help. The symptom is the vehicle will randomly loose power while driving. It has not set any codes or the mil. I've had a shop diagnose it, and their conclusion is that it randomly loses oil pressure (confirmed with a second sender and a mechanical gauge when driving) and when this happens, the DOD essentially is activated and it goes into V4 mode causing the power loss. At one point, it set a low oil pressure light so we shut it off and restarted it and it was good again. So yesterday I running the car in the driveway at high rpm to help charge the battery which had gone flat. I press the gas pedal to maintain 4K RPM, which it maintains for maybe 20 seconds or so. After that, the rpm starts to wander a bit, and then it just drops back to idle speed even though I didn't release the gas pedal. During this time, I can hear what sounds like an air solenoid or something clicking randomly. I push the pedal farther to again get 4K RPM. Same symptoms and timing repeat with it losing RPM and back down to idle speed. I push the pedal more, this time I'm basically all the way to the floor, WOT. I get to 4K, it makes the ticking sounds, idle wanders, and then drops to idle RPM as before, even though the pedal is pushed to the firewall. I can release it, and repeat the process. During each drop in RPM there is no sudden oil pressure loss preceding the RPM drop, though the pressure does drop as the RPM drops.

So what are your thoughts, LS Gurus? I'm looking at replacing the motor in the vehicle, but I want to be sure doing that is the right thing here.
TIA

 

Are C7 cars in the LS category?

 

Yes. And they have DOD.

I inquired to the shop about the above situation and he said it may be a rev limiter strategy.

 

I would suggest going to https://www.tahoeyukonforum.com/ or https://www.gm-trucks.com/forums/ or put this in the C5 forum.

The majority of people on the C7 forum are just going to tell you to go to the dealer.

 

With 200k+ miles, it sounds like things are just worn out vs being DoD specific.

I've heard that some LS engines have an rpm limit when there's no load but peeking through some of the LS files I have in my library, I don't see it. Doesn't mean it's not there. HP Tuners doesn't show every single function that's buried in the PCM, particularly if it's something no one would typically mess with. In addition, things change over time depending on the specific vehicle, year, and PCM. I don't have any Yukon files.

If the oil otherwise looks clean...you might send it to Blackstone for analysis....if could be the oil pump is going although normally low oil pressure is constant not random. If you do have fluctuating oil pressure...I'd say the engine is on borrowed time.

Below is a screenshot of the DoD parameters for a 2013. Stuff like this tends to be fairly consistent year to year since a change would be a major system upgrade. The absolute values may vary but not the parameters. When you look at the parameters you'll note that the key rpm item is when DoD is disabled....above 3100rpm. Activating DoD is more speed, temp, and throttle position related. The system is activated electrically so it's not going to randomly activate due to low oil pressure.

 

Thanks I'll check those out. I figured since this might be a DOD problem and C7 is the first corvette to have that there might be some commonality. Hey, at least I didn't get flamed for a non-corvette issue!

 

It's only been a few hours. Just wait.

 

c7 is a lt platform not ls. while we do have dod thats about where out ends. traditional injectors vs dfi variable timing vs set timing etc.