Rough idle - normal?

[elugelab]

Hi all, firstly thanks so much for the help so far - had my 2016 V8 Coupe for around 8 weeks now (19k miles, no modifications) and this forum has been super helpful.

My latest question though - do all cars have a slightly rough idle? It runs fine when pushing on but cold idle it definitely misfires quite regularly. Have done some searching on here and read about people with rough idle and EMLs on etc leading to injector replacement. No EML from me, nor any significant smoke out the tailpipe beyond the usual cold start condensation. The inner tailpipes I’d say are reasonably sooty compared to the outers, which I guess is relatively normal given they do the job on cold idle until it goes into Dynamic. Warm idle I’ve not noticed it, so I’m guessing it’s just cold start issues rather than anything more pressing.

Should I expect the car to have a perfectly smooth idle on cold start? Or should I get this checked out?

 

[RPSN]

There’s no rough idling or misfiring issues on my V6S.

You should get it checked out.

With regards to the V8 rough idle on cold start, have a read through this.... https://www.ftypeforums.co.uk/viewtopic.php?f=27&t=5233

 

[elugelab]

Thanks RPSN, that link is helpful. I’m unsure of whether I’m just being paranoid or not - my symptoms sound much less extreme than what other posters have suggested. I’ll get it checked out.

 

[rtmyers1]

My p300 idles rough as well... Can feel a vibration in the car, not horrible, but the rpm is about 700 to 750 based on the car gauge and if I increase it to over 800 it is smooth. Will ask the dealer at next oil change if there is any way to adjust... My guess is they want the lowest possible idle for air quality...

 

[Tel]

Hi all, firstly thanks so much for the help so far - had my 2016 V8 Coupe for around 8 weeks now (19k miles, no modifications) and this forum has been super helpful.

My latest question though - do all cars have a slightly rough idle? It runs fine when pushing on but cold idle it definitely misfires quite regularly. Have done some searching on here and read about people with rough idle and EMLs on etc leading to injector replacement. No EML from me, nor any significant smoke out the tailpipe beyond the usual cold start condensation. The inner tailpipes I’d say are reasonably sooty compared to the outers, which I guess is relatively normal given they do the job on cold idle until it goes into Dynamic. Warm idle I’ve not noticed it, so I’m guessing it’s just cold start issues rather than anything more pressing.

Should I expect the car to have a perfectly smooth idle on cold start? Or should I get this checked out?

Misfiring idle is not normal. These engines do feel a bit lumpy on a cold morning though.

Talking of injector issues and the rising number of cat failures I'm reading....
These engines,both the V6 and V8 are big lumps that generally don't see much power demand in 'normal' driving to and from work, town, social trips etc.

We also feed them on this new Bioethanol crap, unless you're lucky lucky me and have % Bio added (E0), thanks Esso! I've seen quite a few injectors out of F-Types and they are black, sooty and blocked.
This is a recipe for disaster with extremely tight tolerances (especially seen in the trigger part of the solenoid), they basically gum up with soot and crap.

Don't worry though, and this may solve your issue, the engine needs what is know in the trade as a good 'caning'!
It needs to get hot and have the right pedal buried into the carpet for as long as you can (remaining on the right side of the law of course) to clear the aforementioned crap out of the engine into the cats, until they get hot enough to burn their crap off too!
I'm sure most people do not do this, and there is the root cause of most of the issues; rough idle, the possible precursor to solenoid failure and then cat failure.

Take it or leave it, that's my prognosis after 8 years of happy ownership...as well as E0 petrol I do use very concentrated solvent additive in the fuel ( UK made ) to keep the gunge diluted.

 

[Anonymous]

I'm entering year 6 of ownership and 44k miles, no lumpy idle here. I do agree with Tel

Kept religiously to service schedule (except rear diff oil which needs doing more frequently) and always let engine fully warm up, super unleaded fuel and use the full performance at least once a week. Never used a drop of oil, never seen a battery charger, never had any mechanical issues. The engines and cars are ment to be used.

Back to the OP. If your going to a main dealer then book the free winter health check and mention the cold lumpy idle. Rather than paying for diagnostics.

 

[elugelab]

Thanks for the extra help - all makes sense. Tel - what additive do you use? I've put one bottle of BG44k through it so far, got another one waiting for a few tanks' time.

Will certainly take your advice about giving it a bit more beans.... difficult on a wet public road with 550bhp through the rear wheels but I shall try!

 

[Tel]

Will certainly take your advice about giving it a bit more beans.... difficult on a wet public road with 550bhp through the rear wheels but I shall try!

Wind it up gently and progressively...they're fine. Being short if you stamp on it, the front will overtake the back!


Key thing is if you crack the window slightly you'll soon smell when the cats are up to temperature, they stink of rotten eggs when they are catalysing! That's the time to keep the red hot gasses going through them to turn the soot into ash.

I'm not overly comfortable endorsing products that I cannot prove worthy, but I have tried a couple. Some high in PEA which is what the internet prescribes. Expensive and seemed to make diddly squat noticeable difference.
I use PIC24 https://www.amazon.co.uk/Hydra-Petrol-Treats-Injector-Cleaner/dp/B01D32LP7S/ref=sr_1_1_sspa?keywords=injector%2Bcleaner&qid=1673007420&sr=8-1-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

I like the fact it is super concentrate, so a little goes a long way. Old engines don't like it, I know because I've tried it on my old Brit bike. My newer injection Duke was fine and I ran a couple of tanks through that in the summer. More crud was deposited on the exhaust exit than normal - How do I know, because I'm anal and clean inside my exhausts too! YMMV

As I say, I'm lucky to have 0% Boi Eth in premium petrol down here, I run the solvents just to air on the side of caution if I'm not able to clear the cat's throat...which is ....never in actual fact!

Theses engines are happy to rev and be whipped, don't be afraid, it does them absolutely good.
If you aren't comfortable on road, book yourself on an open pit lane track day and give it a good hiding there!

P.S as SImpleR says, warm up is incredibly important for a large lump of Aluminium, and for any engine come to that. Don't sit at idle, but do drive it gently for the first 5 miles or so....yes I know that 5 miles is good because I have engine oil temperature and diff oil temp amongst others in my F-Type thanks to Torque Pro app, and that's the distance I have found my engine comes up to temperature in. I won't use the power until she is ready to rock.

 

[RPSN]

Thanks RPSN, that link is helpful. I’m unsure of whether I’m just being paranoid or not - my symptoms sound much less extreme than what other posters have suggested. I’ll get it checked out.

Tel - what additive do you use? I've put one bottle of BG44k through it so far, got another one waiting for a few tanks' time.

Will certainly take your advice about giving it a bit more beans.... difficult on a wet public road with 550bhp through the rear wheels but I shall try!

As mentioned in the thread, taking it easy for a while and warming the engine gradually before opening it up is very good practice....I’ve always done this on my cars and bikes. I usually drive sensibly but now and again (certainly not for as long as I can), I give the car a good blast when it’s safe to do so. No issues with idling, misfiring, injectors or cats!

With regards to using extra fuel additives and fuel cleaning system agents in the F-Type (Jaguar specify not to do it), have a read through this....
https://www.ftypeforums.co.uk/viewtopic.php?p=64418#p64418

Copied below.....

Supermarket Super Unleaded is A-OK and I mostly use Tesco Momentum 99. Occasionally I do visit a Shell fuel station and fill up with their Shell V-Power.

Taken from https://www.tesco.com/help/petrol-stations/ - “What are the benefits of using Tesco Momentum99?”......

“Momentum 99 contains a special blend of additives to help keep the fuel system clean and working at its best. Additionally, the higher octane level (99 compared to 95 for regular unleaded petrol) gives improved overall engine performance for those cars that are able to take advantage (generally sportier models).”

I don’t use any other fuel additives, cleaners etc as Jaguar specify not to do this, and for those within the warranty period they state that it could affect the warranty coverage (exhaust emission control systems).

Taken from https://www.ownerinfo.jaguar.com/ "Fuel and Refuelling – Petrol Engined Vehicles" (screenshot attached)

"CAUTION"

“Use high quality fuel with detergent that meets the specification defined by EN228, WWFC5 cat. 5 or the national equivalent. Low quality fuel can damage the engine and reduce engine performance.”

“Do not use leaded fuels, fuel additives, or fuels with lead substitutes, e.g., manganese-based. Doing so may adversely affect the vehicle's exhaust emission control systems and the warranty coverage.”

“Fuel system cleaning agents should not be used, unless approved by the vehicle manufacturer. Inadequate cleaning agents may damage the fuel system.”

Also, Auto Express has a section entitled "What do car fuel additives do and are they any use? Fuel additives claim to improve your car's economy, performance, or both - but do they really work?" https://www.autoexpress.co.uk/car-news/33200/fuel-additives-are-waste-money

Included in the link...."In general, these additives work best on older, high mileage engines that have either been neglected or missed out on regular maintenance. You're unlikely to see any benefit on a newer, well-maintained vehicle."

"The reality is that if you own a car that's less than 10 years old that has been well maintained, there really isn't any need to use any of these kind of additives, as the car's electronics and fuel system will be optimised to deliver the best mix of performance and efficiency in the first place. And if that's the case, it begs the question - if fuel additives are so good, why don't car makers recommend them? And why are they not commonly found at petrol stations across the country? In reality, they sort of are. If you feel like your car could do with a bit of a boost, then a better value alternative than an additive could be to use a higher octane forecourt fuel than regular 95 octane. Even supermarket chains offer 99 octane fuel these days for a few pence more than regular petrol, and leading fuel retailers make grand claims about the effective 'cleaning' that high-octane fuels can achieve."

 

[Tel]

@RSPN - Jaguar specify a lot of things, and you are quite quick at quoting them.
However, from experience, I have learnt that they speak with forked tongue and I use their spiel with the contempt it deserves

 

[RPSN]

@RSPN - Jaguar specify a lot of things, and you are quite quick at quoting them.
However, from experience, I have learnt that they speak with forked tongue and I use their spiel with the contempt it deserves

If you prefer not to listen to the manufacturer’s and other’s recommendations (as shown in my previous reply to the OP) that’s your choice.

Each to their own but there’s no extra fuel additives and fuel cleaning system agents going in my car. From experience, a combination of Tesco regular unleaded, Momentum 99 and occasionally Shell V-Power is all it needs.....No issues whatsoever with engine idling, misfiring, fuel injectors or cats

 

[Lunar]

I’m not sure this is really helping to resolve the OP’s issue though.
We seem to have started going around in circles again.
Anyone have experience or other thoughts on the lumpy cold idle?
In the old days I’d be looking at the plugs and leads.

 

[RPSN]

I’m not sure this is really helping to resolve the OP’s issue though.
We seem to have started going around in circles again.
Anyone have experience or other thoughts on the lumpy cold idle?
In the old days I’d be looking at the plugs and leads.

As you can see from the thread, the OP has had plenty of help to resolve the issue and he’s acknowledged it. Also, it’s good for him to know about the manufacturer’s and other’s (Auto Express) recommendations not to use extra fuel additives and fuel cleaning system agents which could make things worse (see Jaguar’s screenshot in my earlier reply). At least he has an informed choice.

However, I’m sure he’d appreciate some further input on the rough idle and misfiring issue that he is experiencing on a cold start.

 

[Lunar]

Yep, that’s what I said

 

[RPSN]

Yep, that’s what I said

You said nothing of the sort!

Time to get back on track and let other members contribute to the thread if they so wish

 

[PhilB]

I’m not sure this is really helping to resolve the OP’s issue though.
We seem to have started going around in circles again.

Exactly.
Let's keep this one on topic please and stop the petty "last word" scenario and unnecessary bickering.
Thanks.

 

[Moss]

Hi all, firstly thanks so much for the help so far - had my 2016 V8 Coupe for around 8 weeks now (19k miles, no modifications) and this forum has been super helpful.

My latest question though - do all cars have a slightly rough idle? It runs fine when pushing on but cold idle it definitely misfires quite regularly. Have done some searching on here and read about people with rough idle and EMLs on etc leading to injector replacement. No EML from me, nor any significant smoke out the tailpipe beyond the usual cold start condensation. The inner tailpipes I’d say are reasonably sooty compared to the outers, which I guess is relatively normal given they do the job on cold idle until it goes into Dynamic. Warm idle I’ve not noticed it, so I’m guessing it’s just cold start issues rather than anything more pressing.

Should I expect the car to have a perfectly smooth idle on cold start? Or should I get this checked out?

Perhaps just to throw some balance into this thread, I don’t believe you have anything to be concerned over; TADTS….

My 2018 V8 with similar mileage starts up from cold, runs for a minute at around 1300 gradually settling at 650 as it warms through. There is an ever so slightly perceptible, occasional “lumpines” until it is warmed through to normal.
No EMLs or such like.
Slight sooting on the inner tails - which I’d expect - and soon burns off after pulling away.
Car runs on forecourt E10 with no special treats.

My previous 510 XKR Dynamic engine did exact the same for the 40K miles/5-6 years that I ran it.

Can I ask what you mean by this?

do the job on cold idle until it goes into Dynamic

What difference would you expect Dynamic have, to do with idle?

 

[elugelab]

Thanks everyone. Moss - my reference to putting it into Dynamic was to change drive mode to dynamic, when the exhaust opens up fully and all four tailpipes on the V8 are then open.

Good to know Moss that a slightly rough idle isn't unusual. Started it today and it does feel like the odd misfire but it isn't throwing any codes and drives perfectly so just going to go with it for the moment.