Engine: D5: Lumpy at idle when cold

[Bashy]

Hi folks, the engine appears lumpy at idle when cold, almost as if its only firing on 4.5 cylinders, it appears to be better with a little gas though, i also have to give it some gas as i turn the key else it will struggle to start. My initial thoughts was injector but i do not feel any issues when driving, well, not related to this anyway Any thoughts please?

[simonwedge]

Injectors are most likely cause I think, do a leak down test as here: https://www.youtube.com/watch?v=bbQhKjj6jis and see what the result is

[dingov70]

Morning , my first port of call would be to make sure ALL the glow plugs are working / getting power .

Becoming difficult to start as the temp drops is always a good indicator of deteriorating glow plugs , they work ! but not properly and most modern diesel use post heating to ensure cleaner running until the engine is warmed up . Post heating is reduced voltage to the plugs for a few minutes and normally dependant on coolant temperature

This leads to longer cranking of the engine & lumpy tickover when cold that goes away as the engine gets hotter

[The Landshark]

It'd be worth taking a look at the egr valve too

[gumboots]

2nd for the EGR. I just had the same symptom - like a 4/4.5 cylinder on 2006 Euro4 V70 2,4D. The EGR and cooler were removed today. The vacuum assisted EGR valve had a leaky suction actuator (causing loud popping at the filler cap) and the central butterfly was jammed solid. The main EGR valve was also very gunged up and the actuator motor was very stiff to move. Replaced with a 2nd user part and cleaned everything else out, 100% better now.

[Bashy]

Thanks folks, that leak test looks very involved for someone that could just about manage a plug change, having said that, i did remove an EGR many moons ago, not on a volvo though, probably one of my Lagunas.

Glow plugs i can do though, im sure i have deffo done them before, then again, not on a Volvo.

Something i did notice the other day though, poss coincidence but...

A few seconds after start i put it in neutral (cant remember why now) and the lumpy idle was gone, back in to park and still gone, normally it lasts a few minutes im sure....

[Turbodave]

Mine is also lumpy at idle be it hot or cold.

Thus far I've cleaned out the intake elbow and the EGR (but in situ) and then replaced the TCV and cleaned the boost control valve and whilst it feels more eager, it still idles poorly. It does pop with the cap off so I vacuum tested the engine mounts - rear is spot on, front builds a vacuum and very slowly drops it so have bypassed it which reduced the popping slightly but no change to the rough idle. Runs perfectly smoothly as soon as you dial in a few more RPM but at idle, it's crap. I'll do an injector leak down test but the recent MOT emissions were spot on and it drives well, returns reasonable MPG but you never know.

[Bashy]

Just to update a little on this, not had it looked at yet biut what i have noticed is this, If i put it in neutral the issue goes away, so that tells me a few things, its not the plugs nor the injectors, its related to Park, also, if i put it in Park just before motion is entirely stopped and it rocks, you can feel the rough idle cut in and out with each rock of the car......

[Bashy]

Hi folks, not got round to the leak test yet, prob more cause i can start it easily using the above method.

I am about to buy the tubing, does anyone have the specs of the tubing, namely the ID and OD please?

Looks like i need to buy some bottled water too lol

Would also like to investigate why i get the laboured engine when in park.
Its quite hard to explain what i mean but i will try.

When in neutral, the strain is off the box and engine is removed.

Now, imagine you parked on a incline, (steep or slight, up or down, it doesn't matter). That small amount of play that you get in park (that little play when you don't come to a 100% complete stop and stick it in park, that rocking motion) is no longer there as the force is now on the box, make sense? If you then put your foot on the brake and put it in neutral, you then take that strain off the box thus stopping the laboured engine.

I hope that makes sense, i always over complicate things. But that is what i mean, if i put it in park and the wheels are not on level ground, even a small rock could make it roll enough to hit the end of the roll/motion/play/rock, whatever its called, if it does that, the car will struggle to start when 100% cold unless i remove that strain off of park, ie neutral, or if i can release that strain and put it back in park when its stopped the rocking motion, then it will start with a little feathering, that part is down to injector 1 though i think, hence the 2nd paragraph

Look forward to you input

[Xc90noobie]

Hey Bashy, did you ever get this resolved? Be good to know as mine has the exact same problem. Thanks