D4 Rough Running with A/C on...

[Celtoid]

Just over the last few weeks my D4 (3.0l) has developed a habit of running really rough when the A/C kicks in, usually just after start up.

Which is sort of odd, as I may have only turned the car off for a few minutes and then it does it again.

The rough running goes away shortly afterwards.

It feels like there is more resistance on the compressor than there should be, as it's a noticable, hard kick followed by the rough and noisey idle for a little while.

Any ideas?

Cheers,

Kev.

[MickM]

I have been experiencing a similar problem with mine. Mine seems to be when I pull up at a set of lights and slip the Gbox to neutral, after 30 seconds or so the revs jump violently up to about 1100 RPM. The first time it happened I looked around as I thought someone had run into me - thats how violent the revs jumped up. I don't recall the problem occurring after startup.
I also haven't tried turning the A/C off to see if that makes a difference.

[Disco4SE]

Done nearly 46,000Klm's in my D4 3.0 now and never had that experience:confused:

Cheers, Craig

[Celtoid]

Mine has done just over 26,000.

And yes, it kicks really hard and revs up to around 11 or 1,200 rpm. And it's seriously noisy...

Turn off the A/C, it's gone.

Don't think it's ever done it when it's been running for a while but I'll make a point of taking it out or gear to see what happens. I usually notice just after start up....even if the car is warm.

MickM, have you talked to LR?

Cheers,

Kev.

[discojools]

I've noticed that with both my D3 (now gone) and me 2.7 D4 that if the ambient temperature is in the high 30s or above that when I start the car the idle is increased for a while and then it settles back to normal.. never noticed anything with the a/c though.

Discojools.

[Graeme]

According to the D4 release info, the D3 & D4 2.7's a/c compressor is always turning whereas the 3.0's stops when its not in use.

[MickM]

Mine has done just over 26,000.

And yes, it kicks really hard and revs up to around 11 or 1,200 rpm. And it's seriously noisy...

Turn off the A/C, it's gone.

Don't think it's ever done it when it's been running for a while but I'll make a point of taking it out or gear to see what happens. I usually notice just after start up....even if the car is warm.

MickM, have you talked to LR?

Cheers,

Kev.

G'day Kev,
I haven't had mine to the LR dealer yet. I had the 25K service done between xmas & New Year, the dealers computer was down. I drove to Brisbane the following day and have been away since then so unable to check any of the faults. I plan to take it back next week on my return to Townsville.

Regards
Mick

[Celtoid]

I've noticed that with both my D3 (now gone) and me 2.7 D4 that if the ambient temperature is in the high 30s or above that when I start the car the idle is increased for a while and then it settles back to normal.. never noticed anything with the a/c though.

Discojools.


Thanks.

In mine it only happens after start...regardless of engine temp. I tried going into neutral at traffic lights to see if being in Drive was masking it but it's gone after a little while post start-up.....so it's similar but slightly different to Mick's issue.


Definately with the A/C on as it goes away the second I switch the A/C off.

Revs increase and the car runs rough and noisy but it's the way the revs increase that worries me....as Mick says, it's like being hit.

It doesn't always happen either.

Cheers,

Kev.

[Celtoid]

G'day Kev,
I haven't had mine to the LR dealer yet. I had the 25K service done between xmas & New Year, the dealers computer was down. I drove to Brisbane the following day and have been away since then so unable to check any of the faults. I plan to take it back next week on my return to Townsville.

Regards
Mick

Thanks mate, I think I need to get mine looked at....besides...it needs a wash.....LOL!!! ;)

[Duck's Guts]

According to the D4 release info, the D3 & D4 2.7's a/c compressor is always turning whereas the 3.0's stops when its not in use.

Sorry, slightly off topic...re the 2.7TD, does that mean there would be no fuel economy benefit from driving with the AC off?

[640Newton]

I get the same thing on my TDV8 RRS, but only in really warm conditions. I run with the aircon almost 365 days of the year, but it seems that when the ambient temperature is above 30C, the compressor goes into overdrive immediately after starting the car. The revs die down again after about 20 secs and then all is good in the world again (although it does sound good when the TDV8 revs :twisted:)

[Graeme]

Sorry, slightly off topic...re the 2.7TD, does that mean there would be no fuel economy benefit from driving with the AC off?
I wouldn't draw that conclusion. I don't know but suspect the compressor uses a variable displacement pump which would mean that its not pumping anything when "off" (zero displacement). It would be very inefficient to run a fixed displacement pump all the time and rely on the heater to offset the cooling when too cold.

[Dorko]

I have a D4 and mine does it often now as the temperature is so warm, plus 35 and she revs high at 1100rpm.

Got LR to check it out, nothing came back as broken or a fault. I actually thought it was my chip making it rev, but after i realise it was only happening in hot weather i assume its the air con.

Just another LR trade mark ;)

Dorko

[Celtoid]

I was thinking that it had fixed itself, as it hasn't done it since my trip to Bribie last weekend. I was wondering if been driven at higher revs for longer had 'cleaned' something....

Then it did it again yesterday....and bingo, it was above 30 degrees. During the week when I've been driving the car it's first thing in the morning when it's cooler and again late in the day.

So that appears to be normal then....?

Strange I didn't notice it last summer but it has been a wetter and cooler year than normal I suppose.

Unlike 640Newton's V8 my 3.0L sounds crap when it does this.....really clattery....sounds like a Toyota......LOL!!!! :wasntme: