Compression Ignition Addict
Join Date: Aug 2006
Location: Tallahassee, FL
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Vibration problem progress...
So I did a few things today to try and figure out/ cure the vibration I'm experiencing at idle where my dash/ instrument cluster has a slight buzz, and I hear a steady and seemingly abnormal hum coming from behind my firewall. The engine sounds like the idle is "wavy" is the best I can describe it. The tach needle only rises and falls a tiny bit, but you can HEAR the irregularity. Anyway, I did this:
1. Changed both fuel filters: the old ones were only about 6,500 miles old. They were mostly gray colored upon removal with some darker spots on them.
Change in vibration- minimal at best. Idles a tad better, but the humming is still there.
2. Loosened the downpipe to cat bolts and v-clamp bolt while idling until change detected: this made a huge difference in exhaust vibration. Whereas before I could hold a wrench to any part of the exhaust and it would vibrate like CRAZY, now the pipes barely hum. Apparently the bolts were way overtightened! Check this if you're having exhaust trouble.
Change in vibration- just like the fuel filters, a tiny improvement, but at least now the whole exhaust system vibrates a whole lot less. Very nice improvement there.
3. Checked my motor mount bolts: checked the four 13/16 in. bolts on each side of the motor that bolt the mounts to the cradle...and guess what!!!
....while the bolts on the driver side were nice and tight...ALL FOUR of the bolts on the passenger side were loose...all barely FINGER tight!!!
So I thought I hit the Holy Grail on this one...I thought it was THE cause of my idle hum/vibe problem...I loosened the bolts on both sides and started the truck...revved it up couple times to get some body torquing. Then shut it off and tightened the hell outta those bolts.
Not really any change. DANGIT!!! Now I'm really annoyed.
The truck has no power problems when you get off idle or get on it WOT. Could it be the ICP sensor??? If you raise the rpm like 50 RPM, the engine smooths out immediately. I tried unplugging the ICP and started it, no change at all. Does that mean anything? Also, I noticed something new listening closely to the engine at idle: If I listen really hard to the engine beyond the normal diesel knocking I can hear a sort of metallic pinging sound that seems layered just below the other sounds of the engine. ???
Also, regarding my turbo moan/fart problem: what else besides driving it hard and running fuel system cleaner through it can I do to cure the probable carbonization/ turbo vane sticking I'm having? Techs chime in please. Any other ideas?
"That which does not kill us makes us stronger"
"The only easy day was yesterday"
2006 F-250 SC 4x2 6.0
High Idle Mod
Diamondeye 4" Stainless Turbo-back Exhaust