ENGINE VIBRATION AT 1000 RPM

OHNO60 · January 12, 2008

ANY OF YOU GUYS EVER RUN INTO A 6.4 THAT HAS A VIBRATION IN PARK AT 1000 RPM'S WHEN WARM? VERIFIED POWER BALANCE OK,BASE COMPRESSION OK,RELATIVE COMPRESSION OK. THANKS IN ADVANCE

Bruce Amacker · January 12, 2008

Did you try pulling the belt and see if it went away?

Good Luck!

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Steve Mutter · January 12, 2008

did you check oil level? crankcase overfilled or filling,when 4.6 and 5.4 's came out in f-150 in 97, if they where over filled I think they would run funny

OHNO60 · January 13, 2008

WELL I PULLED THE BELT YESTERDAY AND HAD NO CHANGE.WHAT ERKS ME IS FRONT CRANK SEAL LEAKING AND BALANCER IS OK,SHORT TERM FUEL FOR CYLINDER 1 IS +10 ALL THE REST ARE NORMAL.PASSES POWER BALANCE,EVEN PASSES ENHANCED POWER BALANCE.HOTLINE SAID PERFORM COMPRESSION TEST,WELL ALL PASSED ON THAT BANK ESPECIALLY #1 CYLINDER.RELATIVE COMPRESSION ALL 0. BRUCE DO YOU KNOW THE GOOD/BAD SPEC FOR SHORTTERM FUEL? I ASKED HOTLINE ABOUT ANY CRANKSHAFT ISSUES BEING FRONT CRANK SEAL LEAKING AND CYL #1 SO HIGH. ONE ENGINEER SAYS NO GOOD ON SHRT TERM FUEL BEING 10 OTHER SAYS OH WELL ITS PASSING ALL TESTING MUST BE ANOTHER SOURCE???? THE ENGINE STARTS AND SHORTTERM #1 IS AT 3.AS IT WARMS UP WE HIT 10. HOW CAN THAT BE GOOD?

GregH · January 13, 2008

I'd say that +10 on cylinder #1 is an indication of a problem.

I'd also double check the flywheel - the owner's demo here had one torque convertor nut installed from the factory. Drove out good on the PDI, but a few thousand miles later developed an engine vibration... It would be a quick check, anyway...

OHNO60 · January 13, 2008

no oil levels normal.Interesting about the torque converter nuts though,hahha. Im going to hook up the EVA like the hotline suggested.They want me to identify if its a first or forth order vibration. maybe swap 1 and 3 injectors to see if it moves.The engineers are dead sure the ids software can identify a cylinder issue,haha. Ill keep in touch. thanks guys

Aaron_Johnson · January 14, 2008

It might be worth swapping dampners with a known good one. I had one that the dampner looked ok but in fact was bad. Check your runout and endplay on your crank as well.

Bruce Amacker · January 14, 2008

I can't give you a pass/fail number for FT but I was going to suggest swapping injectors also. Not a quick test, but I'm willing to bet the injector is junk. I'm not betting it helps your balance problem, though.

Sit in the driver's seat and pay very close attention while you scream the motor up and down from open to closed throttle several times. Pay close attention to how the steering wheel/floorboards feel as the engine passes through the suspicious RPM on it's way DOWN. If you feel a quiver while the RPM is on it's way down, the problem is definitely mechanical (balancer, flywheel, etc.). If you don't feel a problem on the way down it could be fuel. The reason is that the engine is in fuel cut while coming down and any shaking will be mechanical. This takes a good "feel" for the shake as you have only a fraction of a second to sense it as the RPM level decreases. Compare with a known good truck if you're not sure what I'm talking about. I have diagnosed many balance problems this way over the years to determine if they're mechanical in nature.

Good Luck!

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OHNO60 · January 15, 2008

yes we swapped high cylinder 1 with 3 injector.same cylinder 1 is 10+. very odd, vibration analyzer plotted it as a 4th order vibration-crqank,balancer etc.i understand the theory,but why's cylinder 1 so high ans all cylinder balance,etc great?

Aaron_Johnson · January 15, 2008

I wonder when you fix the vibration if the balance rate will go back to normal? Maybe it is the effect not the cause

OHNO60 · January 23, 2008

WELL TRUTH COMES OUT!TECH FORGOT TO ADD THAT DETAIL TO HIS SHOP TICKET. OIL LEVEL WAS OVERFILLED BY ABOUT 4 QUARTS.THE OVERFILLING ACTUALLY CAUSED THE VIBRATION AND NUMBER 1 CYLINDER TO GO TO +10 ON THE SHRT TERM FUEL.DRAINED OIL AND WALLAH VIBRATION GONE AND SHORT TERM BACK TO NORMAL.ENDED UP FILLING UP WITH FUEL AND TAKING A HIGH PRESSURE PUMP. THATS NUMBER 2 OVER HERE. NUMBER 3 WAITING OUTSIDE. HERES TO ALL OUR FUTURES! /forums/images/%%GRAEMLIN_URL%%/cheers.gif