Bad surge while cold.

[portafilter]

Hi all I have a 2.4 puma engine. When I first start up from cold every time I come off the throttle the engine surges quite badly while deaccelerating. Almost to the point where it's bunny hopping. It does go away and become reasonably mild once it has warmed up but it never goes away completely. My thoughts is its the EGR. But does anyone have the same problem and the solution.

[Disco4_tech]

Bad fuel?

[Disco4_tech]

Best to always check your fuel quality first with any performance problem. It's free to take your own fuel sample.

Then again it's only when your taking off the throttle. Could be a drive line problem who knows. It's hard to try and diagnose something like that over the Internet.

[newhue]

cold idling mine surges maybe 50rpm most mornings. 30% of the time it will also do it hot, but has no effect.
When cold and in fist idling along it kind of lurches on and off the drive line a bit. LR can't find anything wrong so I put it down to my gumby driving. But I'm sure I don't rock the accelerator so now a vid recording of the tacho being erratic.

Mine has just had it's EGR replaced. I didn't think it is related really. However yours is doing things different to mine so possibly.
I'd probably look at a fuel treatment and continue it, new air cleaner, and drain the sedimenter. Otherwise turn up the radio and all is forgotten, works for me.

[portafilter]

Pretty sure it's not fuel related. It's clean and I often drain filter. Egr is suspect as apparently it's told to be closed until engine is hot. I suspect gas is leaking past and playing tricks on the maf/map sensor. It can't be drive train as it gets less noticeable once it's hot. Unless there is something else that changes as the engine warms? Fuel map maybe. Therefore fuel pump?

[BilboBoggles]

My old 2.4 (MY09) did that from new. on a cold morning raise the idle slightly and it would miss, and give off white smoke. Apparently this was common on the maps used at that time, and in fact it lasted until about 2011 or there abouts when a new ECU map was applied and then it stopped.

Is your software up to date?

[Trout]

My 2011 puma injectors have always been noisy when cold. I think it has been getting marginally worse. Had land rover keep over night and do cold start test. Replaced a cracked exhaust heat shield which they thought was the cause. Even though it was obviously not that :mad: In the last month or so it has also started to surge badly when its cold and you lift off throttle. Started almost straight after rear diff was replaced so I wondered if backlash was contributing. But as soon as its warm no problem. I think it's an injector issue but maybe it could be an EGR problem. I am almost out of warranty which is annoying when land rover seem to take a few goes to fix every problem.

[portafilter]

so i pulled the EGR out over the weekend and
not much really, it was pretty sooted up but not as filthy as i have seen in some pics. i gave it a good clean and also cleaned the MAF sensor? (the one just before the intake manifold). i noticed that even when closed the EGR does not fully seal, its quite easy to blow alr past the plunger, not much but it would definitely leak exhaust gas. i also pulled it apart and greased the gears and bushes, which did make the cleaning cycle much quieter. noticed to that the return spring is not strong enough to fully close the valve against the friction of the unpowered motor, so i guess it just aids the motor. either that or the spring is just **** and the valve never fully closes. (which is probably the case knowing these weird valved) i tried adding a turn to the spring but then it just bound up, had i thought of it at the time, apart from taking pictures, i could have probably added a bit of tension by shifting the bend that located the spring to the body a little bit further down the length of the spring. also noted that the exhaust gas pressure is always trying to force the valve open, seems to me it needs to go around the other way so that gas pressure is always forcing the seal onto the seat, no biggie but "not how i would do it"
as for a change in performance, the weird surge is still there (not quite as bad) when its cold but it does seem to run a lot quieter, a lot less knocking, and like a said i can hardly hear the chuka chuka from the drivers seat now.