lumpy idle at 900rpm
Discussion in 'Volvo Forum' started by 4play, May 30, 2015.
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The viberation seems to match the engine Rpm. I can hear and feel it, sounds like the rumble noise you hear coming out of the intake normally but there is a little more of a pronounced rumble that corresponds with each engine shutter. The rpm holds completely stable tho.
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Also, I questioned the dealer about a valve issue, and was told they use a tool to measure the valves and if there was one not seating correctly it would not be level again the tool. Mime was good they said.also the viberation feels like a small shutter when accelerating through that rpm range, as well when the engine revs then falls back down to an idle I can feel a shutter at 900 for a split second
Last edited: May 30, 2015
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I you can feel the vibration when the engine is in deceleration Ex: from 1400 Rpm going down to idle and when the engine rev past to 900 hundred you feel the vibration and stop by itself when the engine reach 850 Rpm and lower.
Then i will change my mind and i will say crank Damper or clutch or flywheel problem ?
Ben -
But wouldn't it do it all the time? When engine is cold it's smooth.
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When the engine is cold the engine timing is different . . .
I suggest to you to have a look closely to the egr valve circuit first.
Ben -
Apperently volvo checked it, but the software only aloud them to open and close the valve, they can't do a hold at 50%. But they told me it was operating like it's suppose to.
charlie747 Thanks this. -
Does the EGR valve open depending on engine rpm? Let's say at 850 rpm the valve is suppose to be at 50 percent, and and 900rpm say 60 percent. Maybe it's sticking at 50 percent at 900 but at 950 it jumps through its stuck spot and goes say 65 percent where it's suppose to be?
charlie747 Thanks this. -
I will tell you what i know base on the own experience, on D-13 engine the egr valve reading position in the PTT tool is only a software calculation because there is NO sensor on the Egr valve itself to tell is own position like older model D12D was, then the posittion you read in the lap top is not necessary true, the EGR temperature is better to figure out what's happen.
Remove the egr pipe at the egr mixer and install a temporary plug only to clarify the situation. (My suggestion)
Ben -
The operation of the Egr is more complicate depend of the engine temp, RPM, engine load, Def system operation and many factor (part of the engine software) also the EGR valve and the variable geometry of the Turbo are link together to generate enought back pressure in the exhaust manifold to push the EGR flow through the intake manifold where boost is present. . . . .
Hope it can help you a little bit. . .
Ben
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