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Hi guys my 2016 stingray automatic 25000 miles got it 2 months ago has a intermitent misfire im having trouble finding When watching hptuners scanner #4 cylinder shows sometime misfire at 1300-1700 rpm and sometimes at idle in park. It was mentioned to me about a torque tube vibration causing a misfire ? any one hear about this and is there a way to check it?
There is a TSB for these random misfires but they are for the 2001-2013….other than secondary ignition misfires (plugs/wire) most DIY’ers will find it difficult to diagnose these misfires without some advanced diagnostic equipment….cylinders 1,7,6,4 are the AFM cylinders which may be involved in misfires.
thanks c5 for your response i read the procedure and its the same as gm tsb #18-na-268 2014-2019 but there is no mention of this causing a misfire just noise and-or vibration .The part i have trouble with is i get the misfire reading in park #4 cyl how ever when im driving i cant read misfire counter #4 drops out because of afm . at idle i can hear a change in exhaust sound sounds like a misfire sound but no light on and no misfire counter if this is normal then im getting to overboard with it
thanks c5 for your response i read the procedure and its the same as gm tsb #18-na-268 2014-2019 but there is no mention of this causing a misfire just noise and-or vibration .The part i have trouble with is i get the misfire reading in park #4 cyl how ever when im driving i cant read misfire counter #4 drops out because of afm . at idle i can hear a change in exhaust sound sounds like a misfire sound but no light on and no misfire counter if this is normal then im getting to overboard with it
If you want to start firing parts and you know it’s just #4 you can change the plug and wire on that cylinder…anything over that I’d seek a professional which to me means a diagnostic shop…not a dealership or general repair shop....with the TT the ECM interprets the vibration as a misfire but if you actually feel a misfire you go down that path....don't know if you feel it ??
i feel it slightly and hear it intermit at idle 650-700 rpm bring rpm up a little 900-1000 goes away
As I mentioned for the DIY’er without advanced diagnostic equipment it’s a crap shoot trying to diagnose a misfire…you can try a new plug and wire…what do your fuel trims look like on bank 2 ??…an ignition misfire will show fuel trims around 8-10% or so…an injector misfire will show fuel trims near 20%.
The o2 reading b1s1 104 mv b2s1 99mv im going to do another log at idle until i hear a exhaust noise change and maybe ill see a change i may have to get a oscilloscope to see the ignition pattern thank you for your time and recommendation BALL-Z
The o2 reading b1s1 104 mv b2s1 99mv im going to do another log at idle until i hear a exhaust noise change and maybe ill see a change i may have to get a oscilloscope to see the ignition pattern thank you for your time and recommendation BALL-Z
Those aren't fuel trims. In HP Tuners you can log both Short Term and Long Term Fuel Trims and they'll be a percentage. Keep in mind that not all fuel trims are created equal since injector tip temp, load, etc all come into play. Post a log and I can look at it if you want.
C7s have a bad habit of plug wires popping off so I'd pop the wire off of the #4 coil and perhaps swap that coil with another to see if the misfire follows. If that all checks good, verify the plug wire is seated on the plug. Unfortunately the passenger side is a PIA to get to since the fuse box blocks access.
Do keep in mind that these engines idle rough. If things smooth out just off idle, what you're feeling seeing is probably normal. Your first post says it's there at 1700, your last post says it smooths out off idle.
As someone mentioned, a big disparity n fuel trims between Bank 1 and Bank 2 would indicate an issue.
007- thx for your feed back on hptuners at idle i can see #4 not all the time a misfire on the counter bring rpm up 8-900 rpm all is smooth, in park bring rpms up to 1700 and is shows a misfire on the counter but all is smooth except i hear a different exhaust tone Before i get more crazy with myself im going to see if another c7 sounds the same I may just be me over thinking it
Those aren't fuel trims. In HP Tuners you can log both Short Term and Long Term Fuel Trims and they'll be a percentage. Keep in mind that not all fuel trims are created equal since injector tip temp, load, etc all come into play. Post a log and I can look at it if you want.
C7s have a bad habit of plug wires popping off so I'd pop the wire off of the #4 coil and perhaps swap that coil with another to see if the misfire follows. If that all checks good, verify the plug wire is seated on the plug. Unfortunately the passenger side is a PIA to get to since the fuse box blocks access.
Do keep in mind that these engines idle rough. If things smooth out just off idle, what you're feeling seeing is probably normal. Your first post says it's there at 1700, your last post says it smooths out off idle.
As someone mentioned, a big disparity n fuel trims between Bank 1 and Bank 2 would indicate an issue.
is there any fix for plug wires popping off? Do the msd wires fare better than oem’s?
is there any fix for plug wires popping off? Do the msd wires fare better than oem’s?
I haven't heard of anything full-proof. Seems to happen on occasion with OEM wires, aftermarket wires, etc. Some will say to use a little dielectric around the inside of the boot, others say don't since GM didn't use any. There are 10,000 more opinions about "what works" but it still happens. Luck of the draw.
I think the best thing to do is double and triple check that they're seated if you had them off and you''re reinstalling them and on occasion check them almost like a maintenance item.
I haven't heard of anything full-proof. Seems to happen on occasion with OEM wires, aftermarket wires, etc. Some will say to use a little dielectric around the inside of the boot, others say don't since GM didn't use any. There are 10,000 more opinions about "what works" but it still happens. Luck of the draw.
I think the best thing to do is double and triple check that they're seated if you had them off and you''re reinstalling them and on occasion check them almost like a maintenance item.
thanks for the info. I just put new oem wires on a few weeks ago during my header install. Car went crazy after about 4 miles due to a wire coming loose off a coil. Of course it was on the passenger side which is fun to get to. Ended up being some kind of defect with the rubber boot where it after seating it, it would back off about 1/4” when you let go. Replaced it with another oem wire and so far after a few miles it’s ok.
was considering swapping to msd’s this winter to see if those are more secure
misfire
