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Showing results for tags 'cold start'.
Found 9 results
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First post, So for the last 6 months or so my truck has been throwing P050D cold start rough idle. I'm at 36k on the truck and it's a 2015. I brought the truck into the shop for diagnostics. They confirmed that for 1-2 minutes on a cold start condition, cylinder 4 misfires for about a minute or two then stops. They confirmed this multiple times. They verified no vacuum leaks, spark plugs and ignition coils checked out fine, bore scoped the cylinders and found no issues and no coolant leaks, they did a bunch of rebalancing and program checks, verified the related sensors, essentially everything with the exception of checking the injector itself because of the process and time it takes to do so. I know that these newer trucks send double pulses to the injectors during cold start until the truck warms up then it goes back to normal pulse frequency. I guess my question would be what is more likely? The fact that the injector is bad or that during the cold start the injector isn't receiving the pulses? I imagine that all the injectors would be wired in parallel to an extend and that all injectors would essential receive the same signal so I feel that the later is less likely and more than likely the injector itself. But the auto shop won't confirm that the injector is the actual source of the issue because they couldn't test it.
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I have a 2017 GMC Siearra 1500 with the 5.3L & 8 speed transmission. There is a rattle noise that you can hear at cold start. I have seen posts on this issue and answers seem to be all over the place. When my truck sits overnight or while at work all day, there is a rattle that sounds to me like it is coming from the exhaust. I haven't gotten under the truck to see exactly where the sound is coming from. It typically lasts about 5-10 seconds. If you immediately put the truck in gear after startup the rattle goes away. Any info on exactly what this may be is appreciated. I have seen suggestions of torque converter, heat shield, hole in exhaust, flapper valve, and bad catalytic converter. Can anybody narrow this down to one of these issues?
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2016 Silverado 1500 5.3L 6- speed RWD. Approx 105k at failure. See "Shudder: Root Cause (1)..."https ://www.gm-trucks.com/forums/topic/249007-shudder-root-cause-1-at-higher-mileage/ for issues with tach bouncing and shuddering. Occasionally get cold start code, in L.A. area, usu while in a hilly terrain in early morning. Tried injector cleaner and new spark (at some back-alley shop), seemed to help for 5-7k, but it came back and more frequent. Eventually had a fleet shop look at it, followed GM service guide and checked for coolant leak (none) then replaced injectors- I don't have a lot of downtime, so I wanted to get ahead of this issue. No Cold Start codes but less than 1k later, went into limp mode (Low Fuel Pressure code, I believe), and eventually had to be towed (wouldn't start that day but fired right up the next morning in the shop). Had this truck since 30k, and no notable issues. Mechanics found that the high-pressure pump (fuel injector pump) was missing a bolt head and there was a gap at the pump mounting. Looking at the bolt, it appears to have been over-torqued (threads near shoulder were wore down), but I haven't had issues for over 70k. Either previous owner had shudder/trans issues and mis-diagnosed as misfire, or bolts are inclined for early failure (lots of rough freeway, like L.A., last 50k). Either way new gasket and bolts resolved that issue. -
Hello. My brother seems to have a bit of a weird problem. He recently swapped his belt driven fans for an electrical ones. He did all the wirings and changed the temp Sensor. Although the AC fan works fine, It seems that the radiator fan turns on instantly when the engine is cold, but when the engine reaches the operating temperature it turns off and stays off. What could cause this? Did he flip a wire somewhere? -
Hey guys! Hoping I can get some help on this...my truck out of nowhere started making this horrifying noise on startup, primarily during cold starts. I’m very concerned. -
Hello All, I am new to the forums here and feel this would be a great place to get some info.. On my 2015 Sierra 1500 5.3L (23,000 miles) there is an interesting squeal/squeak noise that I hear on cold starts in the mornings. When the engine is warm or once the weather warms up throughout the day, the start up squeak is gone. It's been going on at least twice a week for the past year and it hasn't really bugged me until now. It could possibly be the belt or a pulley.. I am very well aware of the natural noises that these direct injection engines make (the ticking of the injectors, the cranking sound on start up, etc). I will put up a link to my youtube video of the truck making the noise. (Hopefully the link works). The squeal is right at the 4 second mark. Truck is under warranty and the guys down at my dealership are good to work with so if I have to bring it in I will.. I would just like to not have to deal with coordinating my schedule, obtaining a loaner, etc.. Any input would be great.. Thanks everyone!!! -
Quick video of my GMC flowmaster cat back exhaust. Temp was about 80 degrees but the engine was cold. Nice sounding system especially for the price. Here's the stock exhaust, sorry didn't have my phone pointed directly at the tailpipe.
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Does the 99 5.7L Vortec have a cold-start injector to help get the engine going when it's been sitting overnight or for days and days? My older car has one and I'm having a hard time starting my Yukon after it's been sitting for a few days, so I'm just wondering what is supposed to give the engine that little bit of extra fuel when you're starting it cold?
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When cold, my 6.2L can take as many as 10 full turnovers before it actually starts to run. There's no issue when it's warm. It fires right up. Anyone else's perform the same on cold startup? I only have about 1100 miles on it so I'm thinking it could get better as it breaks in.
