Misfire = Vibrations?, but no codes?
11-21-2009, 09:32 AM
#21
In my lowly LT1, I have been chasing down a vibe that follows the torque curve. Starts at 4.5K RPM and fades out around 5.5K RPM.
Finally determined that the #2 sprak plug wire end was barely making connection with the plug. I would consider just a partial misfire but enough to cause the vibe.
Finally determined that the #2 sprak plug wire end was barely making connection with the plug. I would consider just a partial misfire but enough to cause the vibe.
11-23-2009, 10:25 AM
#22
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The vibration was not fixed from the new pushrods or regapping of plugs.. it is still there, although my idle is much smoother now 
OK, so im really wondering if i am confusing my neutral vibe as being a part of this (in neutral, rev, makes my steering wheel bounce a bit),, maybe its not a part of this at all, reason being as my neutral steering wheel hop has been in the car since i bought it, the vibs only started after the Moser 12 bolt install, or possibly after my header install, which was RIGHT before the rear,, maybe 200 miles inbetween the two....
SOOO, lets just pretend that i have a vib in any gear between 1800 to 2500 rpms, and forget about the neutral thing,, i know my rear is good as its been checked about 8 million times (seems the vibs started sometime after installing my Moser 12 bolt) is there any way to tell if my DS is the culprit, any tests i can perform? ((mods feel free to move this if needed))
thanx for the help everyone, its very appriciated!!!!!
Wayne
OK, so im really wondering if i am confusing my neutral vibe as being a part of this (in neutral, rev, makes my steering wheel bounce a bit),, maybe its not a part of this at all, reason being as my neutral steering wheel hop has been in the car since i bought it, the vibs only started after the Moser 12 bolt install, or possibly after my header install, which was RIGHT before the rear,, maybe 200 miles inbetween the two....
SOOO, lets just pretend that i have a vib in any gear between 1800 to 2500 rpms, and forget about the neutral thing,, i know my rear is good as its been checked about 8 million times (seems the vibs started sometime after installing my Moser 12 bolt) is there any way to tell if my DS is the culprit, any tests i can perform? ((mods feel free to move this if needed))
thanx for the help everyone, its very appriciated!!!!!
Wayne
11-23-2009, 02:30 PM
#23
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The vibration was not fixed from the new pushrods or regapping of plugs.. it is still there, although my idle is much smoother now
OK, so im really wondering if i am confusing my neutral vibe as being a part of this (in neutral, rev, makes my steering wheel bounce a bit),, maybe its not a part of this at all, reason being as my neutral steering wheel hop has been in the car since i bought it, the vibs only started after the Moser 12 bolt install, or possibly after my header install, which was RIGHT before the rear,, maybe 200 miles inbetween the two....
SOOO, lets just pretend that i have a vib in any gear between 1800 to 2500 rpms, and forget about the neutral thing,, i know my rear is good as its been checked about 8 million times (seems the vibs started sometime after installing my Moser 12 bolt) is there any way to tell if my DS is the culprit, any tests i can perform? ((mods feel free to move this if needed))
thanx for the help everyone, its very appriciated!!!!!
Wayne
OK, so im really wondering if i am confusing my neutral vibe as being a part of this (in neutral, rev, makes my steering wheel bounce a bit),, maybe its not a part of this at all, reason being as my neutral steering wheel hop has been in the car since i bought it, the vibs only started after the Moser 12 bolt install, or possibly after my header install, which was RIGHT before the rear,, maybe 200 miles inbetween the two....
SOOO, lets just pretend that i have a vib in any gear between 1800 to 2500 rpms, and forget about the neutral thing,, i know my rear is good as its been checked about 8 million times (seems the vibs started sometime after installing my Moser 12 bolt) is there any way to tell if my DS is the culprit, any tests i can perform? ((mods feel free to move this if needed))
thanx for the help everyone, its very appriciated!!!!!
Wayne
Does the viberation change with speed or rpm? Can you verify the pinon angle? you will need a magnetic angle finder for this. Its really hard to trouble shoot this over the internet.
11-23-2009, 02:41 PM
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lol,, if you ask me, its hard to trouble shoot this with the car right in front of me!!
The RPM's is where its at, always 1800 to 2500, most dominant at 2200, any gear in that RPM range. I do not have one of those angle finders, but the car is still at stock height, etc... the rear and all the supporting new stuff went in at the same time (TA, LCA's, PHB), TA is still mounted to the tranny as stock, DS is stock, but i did change the u joint to the appropriate one for the 12 bolt. I think i can get one of those pinion angle finders at Harbor Freight... not sure about that yet though.
Wayne
The RPM's is where its at, always 1800 to 2500, most dominant at 2200, any gear in that RPM range. I do not have one of those angle finders, but the car is still at stock height, etc... the rear and all the supporting new stuff went in at the same time (TA, LCA's, PHB), TA is still mounted to the tranny as stock, DS is stock, but i did change the u joint to the appropriate one for the 12 bolt. I think i can get one of those pinion angle finders at Harbor Freight... not sure about that yet though.
Wayne
11-23-2009, 03:02 PM
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lol,, if you ask me, its hard to trouble shoot this with the car right in front of me!!
The RPM's is where its at, always 1800 to 2500, most dominant at 2200, any gear in that RPM range. I do not have one of those angle finders, but the car is still at stock height, etc... the rear and all the supporting new stuff went in at the same time (TA, LCA's, PHB), TA is still mounted to the tranny as stock, DS is stock, but i did change the u joint to the appropriate one for the 12 bolt. I think i can get one of those pinion angle finders at Harbor Freight... not sure about that yet though.
Wayne
The RPM's is where its at, always 1800 to 2500, most dominant at 2200, any gear in that RPM range. I do not have one of those angle finders, but the car is still at stock height, etc... the rear and all the supporting new stuff went in at the same time (TA, LCA's, PHB), TA is still mounted to the tranny as stock, DS is stock, but i did change the u joint to the appropriate one for the 12 bolt. I think i can get one of those pinion angle finders at Harbor Freight... not sure about that yet though.
Wayne
11-23-2009, 03:07 PM
#27
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i have something there that makes my steering wheel bounce when reved at idle,, so to answer you question,,yes,, BUT,,, i want to investigate the possibility that the 18 to 25 vibs and the neutral steering wheel bouncing are NOT related... they very well may be, i have always thought they were,, but the steering wheel bounce has always been there, since day one that i have owned this car, and its not horrible, it just kinda bounces,, but the 18 to 25 rpm vibs seemed to have started at some point after the 12 bolt install.
another thing on this is that i do not feel a vib in neutral like i do when driving,, or if i do, its deffinetly not the same, its only the steering wheel bounce which is not limited to the 1800 to 2500 rpm range,, it will bounce before and after that range, some days not at all. Good times.
another thing on this is that i do not feel a vib in neutral like i do when driving,, or if i do, its deffinetly not the same, its only the steering wheel bounce which is not limited to the 1800 to 2500 rpm range,, it will bounce before and after that range, some days not at all. Good times.
11-23-2009, 03:31 PM
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i have something there that makes my steering wheel bounce when reved at idle,, so to answer you question,,yes,, BUT,,, i want to investigate the possibility that the 18 to 25 vibs and the neutral steering wheel bouncing are NOT related... they very well may be, i have always thought they were,, but the steering wheel bounce has always been there, since day one that i have owned this car, and its not horrible, it just kinda bounces,, but the 18 to 25 rpm vibs seemed to have started at some point after the 12 bolt install.
another thing on this is that i do not feel a vib in neutral like i do when driving,, or if i do, its deffinetly not the same, its only the steering wheel bounce which is not limited to the 1800 to 2500 rpm range,, it will bounce before and after that range, some days not at all. Good times.
another thing on this is that i do not feel a vib in neutral like i do when driving,, or if i do, its deffinetly not the same, its only the steering wheel bounce which is not limited to the 1800 to 2500 rpm range,, it will bounce before and after that range, some days not at all. Good times.
11-23-2009, 03:44 PM
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nope, BMR non adj TA is what she has... dont i have to get a new u joint if i remove the one thats on there now? No biggie, i think it was like 20 bux or so,,, i do remember spilling the needle bearings when putting it on (ahem,, dont use a hammer to push the caps on 
) but i did recover them and reset them in the cap,, maybe i missed one or something,, man if it was only that easy.. lol.
) but i did recover them and reset them in the cap,, maybe i missed one or something,, man if it was only that easy.. lol.
11-23-2009, 03:54 PM
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nope, BMR non adj TA is what she has... dont i have to get a new u joint if i remove the one thats on there now? No biggie, i think it was like 20 bux or so,,, i do remember spilling the needle bearings when putting it on (ahem,, dont use a hammer to push the caps on ) but i did recover them and reset them in the cap,, maybe i missed one or something,, man if it was only that easy.. lol.
) but i did recover them and reset them in the cap,, maybe i missed one or something,, man if it was only that easy.. lol.
11-29-2009, 01:09 AM
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pinion angle came to -4 (rear = -1.5,, DS = +2.5),,, from what im reding though, pinion angle would be mph sensitve, vs my rpm sensitive so im not sure if buying a adj ta would help or not (grr) I have a brand new bmr one on there now, non adj of course 
11-29-2009, 10:23 AM
#33
I COMPLETELY feel your pain. My car also has a vibration that varies with rpm. It makes it not fun to drive. I'm checking my clutch/flywheel/pp today...
EDIT: I know it's a long shot, but do you think your vibration may be an internal imbalance in the motor? I know you have done many, many things attempting to locate the source.
EDIT: I know it's a long shot, but do you think your vibration may be an internal imbalance in the motor? I know you have done many, many things attempting to locate the source.
11-29-2009, 05:41 PM
#34
I pulled my pressure plate today and fired it up. The vibration was completely gone. Did you ever try that? I saw on a previous post that you pulled your fly wheel, but I wasn't sure if you tried running it with out the PP/disc.
11-29-2009, 07:42 PM
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no, havnt dropped the tranny yet to check all that out,,, not saying i wont, but trying to explore the easier stuff first before getting into that.
What was the reason you inspected yours?
What was the reason you inspected yours?
11-29-2009, 08:41 PM
#36
I had a vibration from 1200-3000 rpm or at least that's where it was most noticeable. I had the steering wheel bounce like you as well. I will most likely be investing in a monster clutch since they are on sale right now.
06-17-2010, 12:48 PM
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still there,, i can kinda feel a pulsing in my clutch pedal,, id bet money i have a cracked flywheel,,,,,, clutch works great though,, and not ready to get under there yet,,
06-17-2010, 01:23 PM
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I had the same issue last month with mine, i pulled everything multiple times, replaced all the wires even suspected a plugged cat. It ended up being a hairline crack BELOW the threaded sleeve on one of the plugs. They were brand new NGK TR-55's out of the box too, so it happens sometimes. I was just glad it only cost $2 to fix 
The only way i figured it out was while pulling them the entire porcelain part snapped off perfectly. Once i tossed in a new plug all was normal.
The only way i figured it out was while pulling them the entire porcelain part snapped off perfectly. Once i tossed in a new plug all was normal.