Rough idle when warm but ok when cold?

[Grilled]

So I’ve been having this issue on and off for a few weeks where sometimes I’ll find my vrs hunting when idling up and down. 
 

Cold starts it starts and idles fine, it even drives fine hot or cold it’s just when it starts to idle when I’ve stopped it’ll just hunting between 700-1000 rpm (or sometimes less). 
 

I had a new piper cam and larger injectors fitted back in January/February then mapped in afterwards and it has been running great until about 5 or 6 weeks ago. 

 

I am also getting a bit of blue smoke out the exhaust when this starts happening but only then, when I’m driving there’s no smoke of any colour (apart from black on hard acceleration). 
 

Can anyone help me diagnose the issue?

[Grilled]

I’ve been using the car to drive today and have noticed more symptoms maybe. 

It struggles to pull away at low revs, goes to bog down in any gear so I basically have to launch it at around 2k rpm or up the revs when in lower gears when pulling out on a roundabout etc. 

As soon as it hits 2.5k rpm and the turbo kicks in it’s a beaut to drive. No issues at all. 

[Sirlimpsalot]

Have you had the fuel and air filters changed recently? Have you tried cleaning the MAF?

[Grilled]

On 28/05/2020 at 14:31, Sirlimpsalot said:

Have you had the fuel and air filters changed recently? Have you tried cleaning the MAF?

I’ve cleaned the MAF which caused no change, air filter was cleaned a few months back and is ok, fuel filter was done a while back nearly 30k miles ago. 

 

[bmbmdmb]

On 25/05/2020 at 19:26, Grilled said:

blue smoke out the exhaust

Blue smoke is a clear sign telling your car engine is burning oil.

 

What is your oil consumption before and after the new parts fitted?

 

Rough idle could be gunked up EGR. Long allen key set and short needed to remove. There are rubber gaskets that are recommended you replace and paper like gasket below EGR.

 

Different car - a 308 1.6 diesel that had blocked injectors after 50k miles. All 3 replaced after sending off for testing but they are number opposite way and after fitting 3 new ones, a few miles later the rough idle returned with check engine light. 4th injector replaced, still had rough idle. EGR replaced but not at fault. 

Another visit to diesel specialist and it mysteriously fixed itself. Injectors wrongly coded? Poor fitting and not sealing?

 

Were your injectors 'coded' and new or 2nd hand? 

 

Scan with VCDS?

 

Hope you find a solution.

[bmbmdmb]

On 28/05/2020 at 14:31, Sirlimpsalot said:

cleaning the MAF?

Mine was not reading or giving spurious results using live data OBD2 garage scan. Didn't flag any DTCs. There was a mismatch on acceleration at low revs. At higher revs the car had no stutter or hesistation. I cleaned with electrical contact cleaner, but it made no difference, as someone else found on this site. Worth a shot. Replacement easy job. Reconditioned MAF sensor (Bosch) for £70 a few yrs ago. Take your old one and swap.

 

Apparently,thte

platinum coating is very thin and wears out or contaminated?

[bmbmdmb]

On 25/05/2020 at 19:26, Grilled said:

new piper cam and larger injectors

Out of interest, what difference did this make to performance before and after remap? Thanks

[Grilled]

2 hours ago, bmbmdmb said:

Blue smoke is a clear sign telling your car engine is burning oil.

 

What is your oil consumption before and after the new parts fitted?

 

Rough idle could be gunked up EGR. Long allen key set and short needed to remove. There are rubber gaskets that are recommended you replace and paper like gasket below EGR.

 

Different car - a 308 1.6 diesel that had blocked injectors after 50k miles. All 3 replaced after sending off for testing but they are number opposite way and after fitting 3 new ones, a few miles later the rough idle returned with check engine light. 4th injector replaced, still had rough idle. EGR replaced but not at fault. 

Another visit to diesel specialist and it mysteriously fixed itself. Injectors wrongly coded? Poor fitting and not sealing?

 

Were your injectors 'coded' and new or 2nd hand? 

 

Scan with VCDS?

 

Hope you find a solution.

 

Oil consumption seems rather minimal, is haven’t had to add any oil since its last oil change. 
 

EGR has been removed and remapped out correctly for over a year now. 
 

The injectors were sent off the United diesel where the nozzles where fitted and serviced, I got all the flow documentation back with them. 
 

VCDS hasn’t shown anything so far fault wise, things look within tolerance on the logs but someone had suggested to maybe look at injector seals or tandem pump.  
 

2 hours ago, bmbmdmb said:

Mine was not reading or giving spurious results using live data OBD2 garage scan. Didn't flag any DTCs. There was a mismatch on acceleration at low revs. At higher revs the car had no stutter or hesistation. I cleaned with electrical contact cleaner, but it made no difference, as someone else found on this site. Worth a shot. Replacement easy job. Reconditioned MAF sensor (Bosch) for £70 a few yrs ago. Take your old one and swap.

 

Apparently,thte

platinum coating is very thin and wears out or contaminated?

I have seen the MAFs need ‘servicing’ every afew thousand miles by cleaning the sensor, and after a few years they deteriorate and need replacement so I’d thought this could be an issue. 
The fuel consumption has always been a little lower than expecting since before the modifications and I’ve seen a bad MAF can also effect this. 
 

2 hours ago, bmbmdmb said:

Out of interest, what difference did this make to performance before and after remap? Thanks

 

I had the turbo fitted for a few months before the cam and then the injectors so noticed there was a difference for each part. The cam without being mapped in made the revs more lively and it felt more punchy. 
then after the injectors got fitted and mapped in it really made a difference in power but I was let down by my friend who was supposed to fit my SRE clutch before so have had the torque limited lower down. 
 

A power comparison with my work colleagues Tesla model S is that with the turbo alone I had no chance keeping up with him (we share a few miles of different duel carriage ways on the way home) but since the injectors and cam I have actually been able to stay ahead of him and keep the gap - but that car is amazing I really cannot compete around bends or roundabouts haha. We worth both quite impressed with how the fabia performed (in a straight line at least!). 

[sepulchrave]

Must be a single motor model S, the dually will give a sidewinder missile a run for its money!

[bmbmdmb]

I would suspect the injectors working backwards from order of fitting, and as there is no EGR.

 

Question is, why the blue smoke? What sort of bhp and torque is car running at? Is the engine high mileage? I heard some of the tuners like Darkside were using 20w50 (the vw caddy van) instead of the manufacturers recommended oil ( probably 5w30)

 

 

Edited 1 June, 2020 by bmbmdmb

[Sirlimpsalot]

Blue smoke could be a sign of over fueling in a diesel, it could also be a symptom of blocked crank case breathing, but I can't see that effecting idle quality.

[Grilled]

19 hours ago, sepulchrave said:

Must be a single motor model S, the dually will give a sidewinder missile a run for its money!

Haha yes it is but still it’s an incredible motor, if I wasn’t looking to upsize in the next two years or so I’d consider getting one. Would obviously have to be better spec than my work colleague (who is also my senior) 😂
 

17 hours ago, bmbmdmb said:

I would suspect the injectors working backwards from order of fitting, and as there is no EGR.

 

Question is, why the blue smoke? What sort of bhp and torque is car running at? Is the engine high mileage? I heard some of the tuners like Darkside were using 20w50 (the vw caddy van) instead of the manufacturers recommended oil ( probably 5w30)

 

 

Is there a way this could happen after it has been running ok for several months? It’s odd it just started occurring out of the blue but I only drive to work 6 miles most of the time and during the lockdown the roads were empty so never had to stop could’ve taken my a lot longer to notice the symptoms. 
 

It’s coming up to 147k and has a really good service record before and during my ownership. Valve seals have crossed my mind but I’d rather than be a last resort option (like turbo seals) as they are labour intensive. 
maybe sourcing some thicker PD oil could help identify the issue. 
Exact figures I cannot provide as I haven’t had it on a dyno. I have a torque reading from the vcds abs logs but not sure how accurate that is. As a reserved guess it’s likely between 250-280bhp?

 

33 minutes ago, Sirlimpsalot said:

Blue smoke could be a sign of over fueling in a diesel, it could also be a symptom of blocked crank case breathing, but I can't see that effecting idle quality.

Now you mention the CCV I think this issue started happening after the standard TIP was replaced with the larger darkside TIP but in reality nothing has changed as it’s still plumbed in as standard. 

I’m not sure if the maf effects the idle control at all on a diesel but this is maybe where I’ll check first with new hardware. 

 

I sent a couple logs to Piotr from Xman turbos as he offered to look at them, he pointed out I’ve low boost (0.4 bar) at 2k rpm then 1 bar at 2.5k rpm. Not sure if that’s related or just how it was mapped to preserve the clutch. 

[Grilled]

I replaced the MAF sensors a couple days ago but only really made short journeys but already the idle seems better. I gave it the beans on the way home from work and afterwards the idle behaved itself staying steady where it should. 
 

This has now led to showing the symptoms, I’ve attached a video showing the smoke on idle (again only when warm) it’s looks like blue/white do yeah oil and possibly overfueling? Once again when driving it’s fine and no signs of blue or white smoke. 

[iansmith]

'05 HTP was idling rough a year ago until i replaced the air filter and plugs, just repeated same today.

Edited 8 June, 2020 by iansmith

[Grilled]

22 hours ago, iansmith said:

'05 HTP was idling rough a year ago until i replaced the air filter and plugs, just repeated same today.

The rough/erratic idle has stopped now thanks to replacing the MAF, Just the the smoke to diagnose now. 

[bmbmdmb]

On 09/06/2020 at 13:21, Grilled said:

replacing the MAF, Just the the smoke to diagnose now. 

Nice one.

You probably have replaced the boost pipes with silicone ones to seal for boost leaks. Mine is not remapped etc but fitting new boost pipes eliminated smoke.

 

Issues with injectors cause smoking (from exhaust)? 

 

Investigate the injectors?

 

How you getting on ( with diagnosis)?

[Grilled]

On 14/06/2020 at 19:45, bmbmdmb said:

Nice one.

You probably have replaced the boost pipes with silicone ones to seal for boost leaks. Mine is not remapped etc but fitting new boost pipes eliminated smoke.

 

Issues with injectors cause smoking (from exhaust)? 

 

Investigate the injectors?

 

How you getting on ( with diagnosis)?

I have a hardpipe kit with silicones all over including the air box to TIP (only because original one no longer fitted.)

 

I left it a while to see what would happen, mainly if the issue got worse or reoccurred. 
 

Surprise surprise it came back in full force, bad idle and all! 

I didn’t want to pull the injectors off myself within the correct tool so decided to try and get in into a local garage that could but had to wait over a week. So I pulled the turbo off to check it over and sure enough there was oil all swirled about. 

Shame as turbo hasn’t even been fitted a year, I guess it was a dud but it was sat around too long to be under warranty now. 
 

Once it’s running again I can see how the idle goes but I suspect it was turbo related as well. 

[sepulchrave]

Oh dear, you need a new CHRA cartridge fitted, that turbo is toast.

[Grilled]

3 minutes ago, sepulchrave said:

Oh dear, you need a new CHRA cartridge fitted, that turbo is toast.

I’ve a newer gtd2062vzk to pop in, however it’s a tighter fit than the gtb2060vklr. 
The silicone for the TIP doesn’t fit over the gtd’s compressor inlet and I can’t fit the OE TIP with a 80mm to 57mm reducer because it’s fouling on the aircon pipework 😩 

I’ve one in the post coming tomorrow that should hopefully fit with the larger TIP, I need it on the road to my clutch appointment Saturday... it’s all go go go! 
 

It’s going to be horrendous to drive because the exhaust supplied is pressing up on the hanger bracket and I won’t have time to get it to a fabricators to sort it now - It’ll get there in the end eventually I’m sure but it’s all rather overwhelming at the moment! 

[Grilled]

So little update, after new turbo being installed there’s no longer any smoke. 
 

However it is still hunting at idle sometimes! I haven’t driven it much since I needed a new downpipe and the one I had supplied with the turbo wasn’t the best fit, so after having the new one made and installed today I’ve done a little driving across town. 
Seems to once again drive perfectly fine then it like, maybe starts to play up at low revs? Bogging down pre-boost. 
 

Would the duel mass flywheel have anything to do with this, I noticed earlier when I was parked up and idling (when it wasn’t hunting) that the revs dropped maybe 100rpm or so when I depressed the clutch pedal?

[sepulchrave]

The reason the revs drop when you press the clutch is that there is a switch on the clutch pedal and the ECU drops the revs to unload the gearbox so you can select a gear easier, most modern vehicles do it.

[Grilled]

14 hours ago, sepulchrave said:

The reason the revs drop when you press the clutch is that there is a switch on the clutch pedal and the ECU drops the revs to unload the gearbox so you can select a gear easier, most modern vehicles do it.

Never noticed it before, but that’s what happens when you start looking for problems - that and this is the newest vehicle I’ve owned, everything else is/has been pre 90’s tech pretty much! 
 

I thought I solved it today when I turned my air con off and it seemed fine, but noticed later the issue persisted but didn’t fluctuate as much. 
 

I was thinking maybe my DMF is in the way out, I don’t think it’s making a knocking noise all that bad however it is one of the symptoms of it (also stumbled across this thread which was useful). 
I needed to install my SRE clutch and new DMF anyway, it’s being done in two weeks so I guess we’ll see if that resolves the issue then.