bad injector

[Aug]

Just sharing my experience. I have a 2014 SS, 19k miles. Since about 12k (hard to say exactly when) it has sort of "stumbled" on cold starts. Stumble may not be correct as that seems more pronounced than it really was. Essentially when engine was cold, when starting it would start right up and immediatly seem almost like a slight misfire, but then catch itself and all seemed fine. This was very very subtle. I ignored it for a long time. In addition I have had a VERY SLIGHT pinging issue on hard accelleration. I drive the car only about 5k miles a year, so it hasn't really been a priority for me to track down but recently it has bothered me, not because it was getting worse, but because I know it isn't right. Long term and short term fuel trims are completely normal, no misfire codes or any codes of any kind ever. After thinking about it for a while, I decided it probably was a very slightly bad fuel injector. Suspecting it was on the passenger side bank just based on where the pinging sound seemed to come from I replaced all 4 injectors at the same time on that bank. Not only does the engine start from cold now with absoloutley NO stumble, it surprisingly starts quicker, no more pinging, and no question runs smoother and has more power. Oh and it idles smoother now too, not ultra smooth as I think the LS3 just doesn't idle ultra smooth like some other V8's, but smoother than before.

I am surprised at the overall difference this had made and surprised that there were no fuel trims showing a problem. It took just 30 mins to replace the injectors. They were $46 each on Amazon (oddly just 4 days later I see the same seller has them for $50 each). I will test the one's I removed to see which was bad and keep the other good ones as spares. BTW, I did run some fuel system cleaner trhough the system once about 6 months ago, which didn't change things at all.

Just thought I would share my experience. I am sure the dealer would not have done anything to help resolve this, if they even would admit or acknowledge any issue. Espessially because their were no codes or fuel trim issues. I don't mind spending the $200 and doing the work myself, it is simple enough to replace injectors.

[DvKillar]

Steve, you must have a zen-like relationship with that engine to mostly "sense" an issue and nail it down the first time! thanks for sharing!

[frankwjr]

or just damn lucky...buy me a lotto ticket? please?

[Aug]

I think combination of luck and logical guessing. I have been thinking about this for a while, and every time I drive the car I think about it - trying to understand what would cause that very brief stumble on cold starts...bad spark plug? Could whatever it was also be related to or cause the slight pinging too? Are the 2 things even related or not? I doubted the bad spark plug idea, mainly becuase if a bad plug, in my mind that would cause more of an incomplete burn, thus, a richer condition VS a lean condition which would cause pinging. Because of this I instead throught an injector must not be working correctly, not dead, just not flowing like it should. I was going to pull the plugs just to see if one looked different than the others with the idea that this might lend credence to the idea of a bad injector, but I thought why bother because I would end up replacing the injector(s) anyways and the effort to do 1 injector is the same as doing all 4, so, pulling plugs seemed like a wasted effort. Also on the passenger side there isn't much room to get to the plugs - a lot of work for what?

I admit I got lucky on this one. On another car of mine I chased a surging issue for 6 months, no codes, no indication of vacuum leaks or other issues. Tried injectors, plugs, coil on plugs, and I don't even remember what else...finally one day got a check engine light, code indication was vague; an undocumented code but within a range of documented codes pointing to throttle body related items (was a Jaguar and they were sketchy with some codes being valid on certain years but not for other years). Over about 2 weeks the problem became more frequent till one day it just wouldn't stay running. After having replaced many parts previously, I finally replaced the throttle body (nothing left to replace) it and all was good. I guess what I am saying is it can be a bit of luck, but there aren't too many things to go wrong. I am also fortunate that I can spend the money to throw some parts at it.

[christianchevell]

You also may have had just a loose connection at the injectors plug as they are not the best and your replugging them in took care of it. That would have been the first thing I would have done is plug and unplug for checking first. For preventative I use a catch can form elite and occasionally use Lucas upper cylinder lubricant.

[Zakariae]

I'm having a service stabilizer track light and ruff idle sometimes and I saw one of the injectors look kinda greasy or wet the rest all dry I wander if that the problem any I prishaired