Bad Injectors, wires, plug, valve spring
Thread Starter
Racer
Joined: Nov 2008
Posts: 284
Likes: 6
From: Casper Wyoming
Bad Injectors, wires, plug, valve spring
OK, I started noticing a miss especially when cold at higher than normal acceleration, not quite WOT. After taking it in three times the mechanic finds 5 bad injectors, 2 bad plugs, 1 bad plug wire. Mechanic replaces them and takes it out for a test drive, and #7 cylinder valve spring breaks!!! The keepers on the spring kept the valve from dropping into the cylinder but now I have to wait for that part (the spring) to come in. He says that once the spring is replaced all will be well.
I'm worried that all the injectors weren't replaced and that other valve springs could be faulty too. The Dealers mechanic says that under warranty he can only replace what GM allows him to replace and thinks the spring is an isolated incident. Also, I can't have the old injectors or spring because he has to send them to GM for warranty reimbursement. What say you guys???
Oh, forgot to say: 2014 A6 Vert with 7200 miles on it. Driven more aggressively than some others do!
I'm worried that all the injectors weren't replaced and that other valve springs could be faulty too. The Dealers mechanic says that under warranty he can only replace what GM allows him to replace and thinks the spring is an isolated incident. Also, I can't have the old injectors or spring because he has to send them to GM for warranty reimbursement. What say you guys???
Oh, forgot to say: 2014 A6 Vert with 7200 miles on it. Driven more aggressively than some others do!
Last edited by dpb; May 14, 2015 at 10:23 PM. Reason: add car description
Tech Contributor
Joined: Jan 2006
Posts: 4,761
Likes: 240
From: Saint Louis MO
St. Jude Donor '14-'15
...That's a hell of a lot of injectors to go bad, and even assuming the plugs were fouled, that doesn't explain a bad wire... This is a cacophony of issues happening all at once. Doesn't seem to have much correlation unless I'm thinking about this the wrong way.
If there were truly 5 bad injectors, and you're worried that they didn't replace them all, there will still be DTCs being thrown on the bad injectors. If you're worried that everything wasn't replaced as you were told, take it to another dealer, and have them read it in - you'll know if you still have an ongoing issue if there are persisting DTCs.
Safety Car
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From: Albuquerque NM
Moderator emeritus
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
2015 C7 of the Year Finalist
Tech Contributor
Joined: Jan 2006
Posts: 4,761
Likes: 240
From: Saint Louis MO
St. Jude Donor '14-'15
What's sad about this is that the GDS2 DTC system makes it so bloody easy to identify issues with this platform... No clue how a tech could make that many assumptions without the papers to back it up, unless they were just making things up. 
Thread Starter
Racer
Joined: Nov 2008
Posts: 284
Likes: 6
From: Casper Wyoming
Follow Up
OK, I started noticing a miss especially when cold at higher than normal acceleration, not quite WOT. After taking it in three times the mechanic finds 5 bad injectors, 2 bad plugs, 1 bad plug wire. Mechanic replaces them and takes it out for a test drive, and #7 cylinder valve spring breaks!!! The keepers on the spring kept the valve from dropping into the cylinder but now I have to wait for that part (the spring) to come in. He says that once the spring is replaced all will be well.
I'm worried that all the injectors weren't replaced and that other valve springs could be faulty too. The Dealers mechanic says that under warranty he can only replace what GM allows him to replace and thinks the spring is an isolated incident. Also, I can't have the old injectors or spring because he has to send them to GM for warranty reimbursement. What say you guys???
Oh, forgot to say: 2014 A6 Vert with 7200 miles on it. Driven more aggressively than some others do!
I'm worried that all the injectors weren't replaced and that other valve springs could be faulty too. The Dealers mechanic says that under warranty he can only replace what GM allows him to replace and thinks the spring is an isolated incident. Also, I can't have the old injectors or spring because he has to send them to GM for warranty reimbursement. What say you guys???
Oh, forgot to say: 2014 A6 Vert with 7200 miles on it. Driven more aggressively than some others do!
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 43
From: shavertown Pa.
"unless they were just making things up" seems more like it
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Melting Slicks
Joined: Nov 2013
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From: Texas
Not trying to come across as acting as the resident tech expert but I’d have thought a broken valve spring would have resulted in damage to the top of the piston. Am I missing something here? Don
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From: Jacksonville Florida BWO Dayton, Cincinnati, Bloomsbury NJ, Cincinnati
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I believe that the "keepers" on the valve would keep it from drop down and coming in contact with the piston. The problem would be exhaust gas or intake mixture (depending on which spring broke). The broken spring might horse up the rocker, trunion, or something on top????
My $.02
Elmer
Le Mans Master
Joined: Aug 2005
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From: CA.
St. Jude Donor '13-'14-'15
I agree with the others--seems like a mis diagnosed warranty failure--The broken spring can create or simulate other issues that are indeed false--- A broken valve spring can create "false misfires' backfiring etc--Normally they would think it's a secondary ignition failure-How they got to the point of failing injectors is beyond me---