3.0si Lumpy idle

[Ed Doe]

Evening all,

Right I'll start by saying I to have a certain tenancy to be a bit anal retentive when it comes to cars.... And specifically keeping themin tip top shape. So this may very well just be a foible of the car, but I'd like yourlearned opinions on the subject to put my mind at ease...

When I start the car from stone cold this issue is not present, but when starting the car from warm it the idle seems to hunt about slightly for the first 10 secs or so... It then settles down to idle at the normal speed, but it seems to very slightly miss occasionally. I could be imagining it but it seems to have got worse, but then equally I could have not been used to how the car drove to start with.

Now driving. It seems to me that light throttle application causes a bit of a stutter. It's very slight and seems to be accompaniedby a bit of burble from the exhaust. In conjunction with the warm start lumpiness I thought it warranted your thoughts!

The car has just been for an inspection 2 at TWG automotive, and came back with a cleanbill of health....

Hoping I'm either going to get told to just get on and drive it like most of my friends already say, or get pointed in the direction of a ppotential solution!

Thanks in advance!

Ed

 

[bradz]

Did they change the plugs with the Inspection II?

 

[Z4M-2006]

I take it yours has the N62 engine?

If so,they do suffer from injectors clogging....

Maybe a fuel cleaner and italian tune up might help ?

 

[Ed Doe]

Yes they changed the plugs with the service, and kept the old plugs at my request so I could check the condition.

It's the N52 engine which I'm sure is what you meant I'll run some redex through it and see how it responds! Failing that does anyone have any recommendations for an injector cleaning company in the Surrey area?

 

[Z4M-2006]

Oh yea... getting my numbers mixed up again..

Dont use redex,its crap.... Try BG44K..

 

[stupot67]

Hi Ed,

Mine's the same (Well the slight missing at warm idle at least), but no hesitation when driving - changing the plugs and swapping the coil packs made no difference, no EML errors stored or pending, so I've put it down to being a "Feature".

Stu.

 

[Ed Doe]

Thanks for the responses chaps; sorry my last one was short; typing replies out on my phone is a pain!

So yeah, to clarify my perception of the 'issue' if it is that...; when I'm at about 2k, when coming off the throttle, it burbles slightly whichI'd expect in a sporty car anyway... When I then go back on the throttle very lightly, it feels a bit jerky, and incrementally increasing the throttle position from very light throttle position the increase in acceleration doesn't seem to be linear....

Now I've also had the CDV delete about 2 weeks ago, so it may also be that, but changing gear it seems to be harder to catch the revs right. I assume that's just the nature of the CDV mod...

As with you Stupot67, I've not had any error messages/EML or any other issues, just these traits I've become more aware of during driving...

To be honest I'm probably just being a big girls blouse about it, and just need to man up and drive it. I guess I'm just keen to make sure all is exactly as it should be before getting it mapped early October... :driving:

 

[MHZ4C]

Hi Ed,

I also have a slight stutter on warm idle. Nothing major, but I can feel it. No lights on the dash or anything to suggest it's a problem. I run on VPower, which did help when I first bought the car. Loads of rubbish came out of the exhaust on the first 10 or so tanks, but not so much now, the exhaust tips stay clean.

I concluded the same as Stu, a feature. No problems with power delivery or hunting idle.

Previous cars hunting at idle were linked to a dirty throttle butterfly valve or dirty MAF sensor, but not sure if it's the same setup in the N52. Still learning! Hope it's nothing more than an Italian tune up a light cleaning for you!

 

[Ed Doe]

OK, so I have to ask.... What's an Italian tune up?

Thanks for the feedback MH, glad to know it's not just me!

I've always run mine on Shell Vpower too in my ownership; I figure if it's a sport car there's just no point in not giving it the best!

As far as I was aware the n52 doesn't have a throttle butterfly valve except as a failsafe if the valvetronic system develops a fault, and also to regulate power going to the wheels for the DSC. I always understood the valvetronic system totally controlled air inflow by varying lift and duration during normal running on these engines. I think the map sensor can cause issues from what I've read on other forums....

After the feedback so far I think I'll just be a bit less of a hypochondriac and drive the car and enjoy it until something significantly changes or a fault develops!

Thanks guys, and MH do let me know if anything changes with yours to warrant further investigation

 

[MHZ4C]

Hi Ed,

My understanding of the correct 'local garage' application of the Italian Tune-up...
Get the engine and oil nice and hot. Pull off, select 1st / second gear, and hold the revs nice and high, with periods of normal driving to cool the engine a bit.
This gets everything flushed through, and can remove any rubbish that might be causing problems, and can help improve the catalyst performance if you're boardering on an MoT fail.

This was learnt on my first car. I've not performed it on the Zed, just made a conscious effort to give it a proper drive every week, once the oil is up to operating temperature.

In 2 years and 12000 miles it hasn't gotten any worse. If anything, it improved in the first 6 weeks running V Power through the car. This may just have been a change from being driven slowly, to driven properly, rather than the fuel. A lot of soot came out with the first few tanks, now I don't get anywhere near as much on the tail pipes.

I'll get in touch if anything changes!

 

[srhutch]

These cars do need to be driven. when I had issues with the HVA's the dealer read out a bulletin to me. Basically it said "Tell the customer to drive the car harder" I did assure them that that wasn't the problem. :lol:

 

[Ed Doe]

Haha! Oh I don't think I could ever be accused of not driving the car hard enough! :lol:

If you saw my commute....

But yes probably over the last few weeks I have been a bit too kind to it... I managed 35mpg on the way to and from Silverstone yesterday. Definitely too much!