sounds like a cylinder has dropped out, but no cel.
06-28-2012, 11:18 AM
#1
sounds like a cylinder has dropped out, but no cel.
so I was out driving the z about a month and a half ago and when I stepped on it, the car started to sound it wasn't firing on all 6 cylinders. so I imediately let out of it. after I let out of it it began to run just like normal. fast forward about 20 minutes I was on my way home and I stepped on it again to see if it would do it again and it started to do the same thing except this time it did not go away when I let out of it and it got progressively worse. I was able to limp it the mile or so back to the house but by this point it sounded like a cammed out vet. I pulled the plugs and they all looked fine except the passenger side rear which had some (not a whole bunch) oil on it probably from the valve cover leaking. through out this whole time the cel light never came on once. the car still starts right up, and doesn't smoke and will hold idle rpm steady as a rock, but it sounds like it is not firing on one cylinder at all. I can't hear any kind metallic pinging or anything normally associated with a bottome end failure. I now suspect that a coil pack is burnt out or that an injector is faulty (the injectors are relatively new, they have less than 1.5k on them)
I checked the coil packs visually but I can't see any blistering on them, any ideas on what else could be wrong? how do I check the coils with a multimeter? is there anyway I can check the injectors to see if they are functioning?
the mods to the car are, greddy tt on a stock block, dw600 injectors, CJM stage 0 RFS, GT maf, osiris tune, running waste gate spring pressure, walboro 255 fuel pump.
I checked the coil packs visually but I can't see any blistering on them, any ideas on what else could be wrong? how do I check the coils with a multimeter? is there anyway I can check the injectors to see if they are functioning?
the mods to the car are, greddy tt on a stock block, dw600 injectors, CJM stage 0 RFS, GT maf, osiris tune, running waste gate spring pressure, walboro 255 fuel pump.
06-28-2012, 03:10 PM
#6
Not that i could tell, my exhaust is pretty loud, and I lost a bit off hearing overseas but, to the best of my knowledge no it's not. i've heard detonation on other people's cars and it didn't sound that way to me. Also when i looked at the plugs they didn't show any signs that i could see of a lean condition. But again I'm no expert. I will try to post pictures of the plug with oil on it.
06-28-2012, 04:27 PM
#7
You will have a hard time hearing detonation with a loud exhaust... but steady misfire is actually easier to hear with loud exhaust. You can also tell by holding a sheet of paper on the exhaust pipe...if it sucks in against the pipe you are misfiring.
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06-28-2012, 06:08 PM
#9
Most deffinately does sound like a boxer motor. Very much like one of the cylinders is not firing at all and it feels like it is out of balance much as you would expect from a cylinder with 0 combustion. To test the resistance with a multi meter would i just attach one lead to the center prong and one to either the left or right prong. If does anyone know what ohm values a properly functioning coil pack should read. Is it somehow possible that the cel is not being triggered because of the osiris flash? If at all possible i would like to try and avoid starting the car until i get this sorted out so as not to wash out the cylinder if in fact it is getting fuel and no spark. Thanks for all the suggestions.
06-28-2012, 07:52 PM
#10
this is the spark plug that I found oil on, there was also some oil on the socket and a tad bit more on the boot. the car hadn't been run for about a month and a half as of yesterday when I pulled this plug and took this picture so I guess is is possible that the oil was worse at some point and receeded of the course of time. right after I took this picture I cleaned the plug, coil pack, and the inside of the spark plug well. after that I reinserted the plug and put everything back togeather and started the car to see if that was the problem but it was not. although I can't rule out the possibility that the oil was bad enough at some point to fowl and short the coil pack.
this is a close up of the tip of the same plug (but they all pretty much looked this way). I can't see any obvious signs of detenation on the plug but maybe on of you guys knows something that I don't.
this is a close up of the tip of the same plug (but they all pretty much looked this way). I can't see any obvious signs of detenation on the plug but maybe on of you guys knows something that I don't.
Last edited by nathanwl2004; 06-28-2012 at 07:53 PM.
06-29-2012, 08:43 AM
#13
Ahh did not know that. So if one coil isn't firing then I suppose if i pull all the coils 1 by 1 then if i get to a coil that doesn't make the idle sound worse then I'll know that coil is not functioning right? Like i said the only thing i'm worried about is cylinder washout.
06-29-2012, 08:54 AM
#14
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similar to what happened with me. no CEL light. just random miss.
I wouldnt worry about cylinder wash out. and I'd pull the plugs on the coil packs and test it that way first. if you dont find anything from that test, swap the coil packs around (taking note of which you swapped to where) drive it, then read your plugs. Im willing to bet you'll find it by doing that. if its not a coil issue, try the same thing with the injectors. swap them, drive it, read the plug.
my issue was a stuck injector. similar symptoms. found it by swapping things around. I never got a specific missfire until after it was happening for quite some time. but still, it wasnt cylinder specific.
I wouldnt worry about cylinder wash out. and I'd pull the plugs on the coil packs and test it that way first. if you dont find anything from that test, swap the coil packs around (taking note of which you swapped to where) drive it, then read your plugs. Im willing to bet you'll find it by doing that. if its not a coil issue, try the same thing with the injectors. swap them, drive it, read the plug.
my issue was a stuck injector. similar symptoms. found it by swapping things around. I never got a specific missfire until after it was happening for quite some time. but still, it wasnt cylinder specific.
06-29-2012, 07:46 PM
#15
similar to what happened with me. no CEL light. just random miss.
I wouldnt worry about cylinder wash out. and I'd pull the plugs on the coil packs and test it that way first. if you dont find anything from that test, swap the coil packs around (taking note of which you swapped to where) drive it, then read your plugs. Im willing to bet you'll find it by doing that. if its not a coil issue, try the same thing with the injectors. swap them, drive it, read the plug.
my issue was a stuck injector. similar symptoms. found it by swapping things around. I never got a specific missfire until after it was happening for quite some time. but still, it wasnt cylinder specific.
I wouldnt worry about cylinder wash out. and I'd pull the plugs on the coil packs and test it that way first. if you dont find anything from that test, swap the coil packs around (taking note of which you swapped to where) drive it, then read your plugs. Im willing to bet you'll find it by doing that. if its not a coil issue, try the same thing with the injectors. swap them, drive it, read the plug.
my issue was a stuck injector. similar symptoms. found it by swapping things around. I never got a specific missfire until after it was happening for quite some time. but still, it wasnt cylinder specific.
After looking at all the coil packs and seeing no blistering i'm really starting to wonder if it is not a stuck injector. Which is kinda ironic because I changed to these injector to avoid exactly that. I'm gonna try the coil pack test this sunday (helping a friend move tommorrow) atleast that should tell me which cylinder is not functioning I'll let you guys know how it goes.
I appreciate all the help
-Nathan
07-03-2012, 09:18 PM
#16
Well after spending some time testing and swapping I can't conclusively nail down the cause of its cammed sound. At this point I'm going back into a very busy and difficult class schedule so I won't have the time, patience, energy or patience to try and figure it out. So off to the shop it goes.
07-04-2012, 07:14 AM
#17
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Hey sorry I didn't see you quoted my post a few days ago. The misfire was continuous in my case. I would try the injector swap before taking it to a shop. Could save yourself some money.
12-23-2012, 09:52 PM
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Sorry to bump this guys but what are the symptoms of a cylinder not firing? My car sounds like a boxer engine, but only when warm. It has a knock that does not correspond to anything I've read about, I changed the spark plug and I'm starting to wonder if it is an injector problem or the coil pack isn't firing. It's only coming from 1 cylinder.
