Makes sense to me.
2017 Yukon 6.2 suddenly running very rough and check engine light
- Thread starter RhondaHonda
- Start date
Makes sense to me.
Fundamentally, every engine needs fuel, spark and compression to run properly. When you have a misfire, focus on those 3 items and you will often find your issue.
Esp. on the 2014+ GM trucks/SUVs. They've been having quite a lot of probs with injectors on them, AFM/DFM aside.
Found this bulletin for replacing all 8 injectors under an extended coverage but only if you are in 13 states which I’m not. It applies to my model year and RPO L86 for the 6.2. I’m wondering if GM would work with me as I hate to replace one injector and then others fail in the next few months, assuming this is the issue.
Edit-replacing the faulty injectors
Last edited:
It doesn't say anyone automatically gets a new set of 8. Dealer will conduct an in-place pressure test (not a circuit test) on each injector and replace only those that fail.
It has one further up front but the O2 sensors are exposed.
I got 12 volts ignition on, engine off at the injector wire harness for both the problematic # 6 cylinder as well as the #4 cylinder and 14.5 volts when the engine was running at both so it appears the wiring is ok, at least to the limit of my abilities l. Disclaimer-I’m not well-versed in electrical diagnostics.
Put a stethoscope on that injector and listen. See how it sounds compared to others.
I tried that with a long handled screwdriver but couldn’t really hear a difference. This doctor doesn’t have a stethoscope but I’m starting to deduce that the fix is going to be above my current physical limitations due to a back surgery and abdominal surgery in the last 3 months. I am just hoping to narrow it down before going to the dealer to limit the amount of fleecing I get.
There are 4 pins on the injector. Do you know which ones I’m measuring resistance across?
Got 3 ohms across 2 pins and 11.8 across 2 others on 3 different injectors.
The Injectors are under the Intake Manifold & a thick foam pad....No way you're getting to the actual Injector connectors without pulling the Intake nor are you getting to the breakout connectors for the Injector Sub-Harnesses.
The 4 pin connectors are the Ignition Coils.
The easiest spot to breakout the Injector Drivers is at the PCM....
The 4 pin connectors are the Ignition Coils.
The easiest spot to breakout the Injector Drivers is at the PCM....
Thanks for that! I’ve never messed with any GM individual coil engines and even wondered if I was checking in the right place. Is there any reason I shouldn’t drive this 5 miles or so to the shop or would I be better off towing it?
What "Shop"? Are they familiar with Ecotech3/LTx engines? Last thing you want is to pay for a mechanics learning curve on these.
A flashing SES lamp means the misfire is bad enough to damage the catalyst. In fact....Ecotech3 engines are notorious for setting Catalyst Efficiency DTC's after Injector related misfire events. I believe your Catalyst's are still covered under federal emissions warranty.....But you will need the misfire/Injector circuit fixed first.
A flashing SES lamp means the misfire is bad enough to damage the catalyst. In fact....Ecotech3 engines are notorious for setting Catalyst Efficiency DTC's after Injector related misfire events. I believe your Catalyst's are still covered under federal emissions warranty.....But you will need the misfire/Injector circuit fixed first.
I think he was planning to take it to the dealer.
I’ll likely take it to the dealer as I don’t have any independent shops that I’m familiar with. If there’s any chance that GM covers any of it as part of a TSB/warranty/cost sharing the dealer is my best option.
I’ll tow it. It was driven about a mile from where the light came on and it started running rough and then I’ve started it a couple times during my “diagnosis” but don’t want to risk any further damage. Thanks for the input everyone.
My credit card paid the tow and my almost 2 year old was super excited as he loves trucks, tractors and heavy equipment. I’ll post an update once I hear from the dealer.
