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i don't think your hear injectors as much as your hearing the mechanical fuel pumps that are mechanically driven, they will make the sound any time the engine is running there's no mode to put them in, if the engine is moving so are those pumps, you need mechanical fuel pumps for DI you can't get the fuel pressure with electric pumps. mine is a coup and i can hear the fuel pumps when the car is running. kinda sounds like a sewing machine
All I know is that a dude that thinks his fuel injectors just shut off when he goes off throttle has no business diagnosing an engine issue. At this point, I'm siding with the service writer and the technician.
The fuel injectors do shut off when coasting (engine braking), they are electrically controlled. But the injectors don't cause the sewing machine noise. As mentioned, the high pressure mechanical direct injection fuel pump causes the noise.
OP, you mentioned you had some mods done. Do you have the stock intake plenum cover? The stock cover has insulation on it, some of the aftermarket ones don't and will let more noise through.
The fuel injectors do shut off when coasting (engine braking), they are electrically controlled. But the injectors don't cause the sewing machine noise. As mentioned, the high pressure mechanical direct injection fuel pump causes the noise.
OP, you mentioned you had some mods done. Do you have the stock intake plenum cover? The stock cover has insulation on it, some of the aftermarket ones don't and will let more noise through.
Yes, there's actually two different so-called modes where fuel will be shut off: Fuel Cutoff Mode, and Decelleration Mode. As observed in this thread, neither description give quantitative definitions of when the they kick in. But I think also the tick associated with the noise that is heard is coming from the fuel pump - rather than the actual injector firings. I can't find anything written to confirm that, though.
Picked it up yesterday and today I have a warning in my chevy app and it says that my transmission system and throttle control systems have issues and need service soon.WHAT... THE F**K!?!?!?!?!
Picked it up today. Their story now is that all C8s sound like this and this noise is the injectors. So my question was, if that was the case why didn't anyone dismiss it and say that was the problem the first time they replaced the cam, lifters etc? Did I just get lucky and talk them into doing it? Of course they only had 1 C8 that they would let me hear and that was in the used car showroom. They did not sound the same. Here is the pic of the service receipt from the first attempt.
Normally in race motor, if the lifter takes a dump
and you flatten a cam lobe, the ENTIRE motor needs a rebuild.
New bearings, re honed, new rings and possibly pistons.
What happens is that when the lifter takes a dump and flattens a cam lobe, thise iron particles from the flattened lobe circulate through the oil system and wind up embedding themselves in cylinder walls, the soft bearings and into the piston skirts.
When someone loses a new cam when breaking in a flat tappet motor, it is a normal
procedure to rebuild the entire motor and replace any parts that were scored by the metal that circulated through the system. DON'T ASSUME the oil filter caught it!
Maybe its fine but I would never accept a flattened cam lobe repair being inly replacing the cam and the damaged lifter personally. Thats an $85,000 sports car and you are getting a half assed fix!
Normally in race motor, if the lifter takes a dump
and you flatten a cam lobe, the ENTIRE motor needs a rebuild.
New bearings, re honed, new rings and possibly pistons.
What happens is that when the lifter takes a dump and flattens a cam lobe, thise iron particles from the flattened lobe circulate through the oil system and wind up embedding themselves in cylinder walls, the soft bearings and into the piston skirts.
When someone loses a new cam when breaking in a flat tappet motor, it is a normal
procedure to rebuild the entire motor and replace any parts that were scored by the metal that circulated through the system. DON'T ASSUME the oil filter caught it!
Maybe its fine but I would never accept a flattened cam lobe repair being inly replacing the cam and the damaged lifter personally. Thats an $85,000 sports car and you are getting a half assed fix!
GM likely made the decision, not the dealer, for a warranty issue this big/expensive. Do you think the OP has an option to decline that? I don't disagree that the motor should probably be replaced - just not sure there is an option to refuse. I think OP should inquire about who made the decision and how it was made - go from there.
GM likely made the decision, not the dealer, for a warranty issue this big/expensive. Do you think the OP has an option to decline that? I don't disagree that the motor should probably be replaced - just not sure there is an option to refuse. I think OP should inquire about who made the decision and how it was made - go from there.
I am waiting on a call back from the rep from GM that I've been talking too.
