Help me read these spark plugs, please
Thread Starter
Launching!
Joined: Oct 2009
Posts: 235
Likes: 0
Help me read these spark plugs, please I have been chasing a vibration that comes in and out of the RPM range.I have had the clutch pack balanced, replaced the vibration damper/crank pulley and sealed the intake leaks. The motor is a 2004 GTO stock internals with headers and custom intake running MAF and IAT.
The PCM is running a stand alone tune, the plugs are NGK TR55-1GP gapped to .040 with about 1K miles on them. I regapped the plugs to .055 with minimal change in vibration around 3K RPMs. From what I can find they are either too hot or there is too much timing. What do you think?
Click the thumbnails for a larger image.
The PCM is running a stand alone tune, the plugs are NGK TR55-1GP gapped to .040 with about 1K miles on them. I regapped the plugs to .055 with minimal change in vibration around 3K RPMs. From what I can find they are either too hot or there is too much timing. What do you think?
Click the thumbnails for a larger image.
I have been chasing one like that for years. Came in at a certain rpm around 40mph
i did mounts all around
tires
intake seals
cleaned the tb up to almost new
swapped the ehxaust and stabilized it with bump stops ect..
did a converter swap with a new flexplate
and i did msd wires with tr55-ix
none of which changed a damn thing. my last few thoughts were that it was resonance from the exhaust that is unavoidable....the transmission itself....or most likely driveshaft, pinion angle or yolk ect.......after that i give up thought because...
i have a feeling that it lies somewhere in my driveshaft/linkage now.
ill find out soon when i swap all that over for the 4l80e. it will be so neat not to have it. i would always avoid that rpm range at that speed like the plauge. at certain points it was like i had a sub in the car, thats how much resonance/vibration I got.
hope this gives you some insight....tackling vibes is no fun unless your a girl.
i did mounts all around
tires
intake seals
cleaned the tb up to almost new
swapped the ehxaust and stabilized it with bump stops ect..
did a converter swap with a new flexplate
and i did msd wires with tr55-ix
none of which changed a damn thing. my last few thoughts were that it was resonance from the exhaust that is unavoidable....the transmission itself....or most likely driveshaft, pinion angle or yolk ect.......after that i give up thought because...
i have a feeling that it lies somewhere in my driveshaft/linkage now.
ill find out soon when i swap all that over for the 4l80e. it will be so neat not to have it. i would always avoid that rpm range at that speed like the plauge. at certain points it was like i had a sub in the car, thats how much resonance/vibration I got.
hope this gives you some insight....tackling vibes is no fun unless your a girl.
Thread Starter
Launching!
Joined: Oct 2009
Posts: 235
Likes: 0
My next step is tuning, looking at my spark plugs the timing may be too high or its running too lean. Anyone agree with that assessment?
If that doesn't work, I could cam it to move the vibration up the RPM band where it is less noticeable.
If that doesn't work, I could cam it to move the vibration up the RPM band where it is less noticeable.
Thread Starter
Launching!
Joined: Oct 2009
Posts: 235
Likes: 0
I did and read other sites as well. I think from what was read that it has too much timing in the tune (mail order) causing it to run lean and making the spark plug look like it is too hot of a plug. I don't have any experience with this so if anyone wants to cofirm or give your opinion it would be much appreciated.
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