Starting issues.....Stuttering and smoke please help :( VR6

[Nick 17 10]

Hello everyone I am in need of a little advice;

For the past week my car has been intermittently struggling to start.

When it starts the car idles really low and begins hunting. I press the throttle down to try and increase the revs and I am met with some excess smoke coming out the back of the car a grey/blue colour and what feels like a misfire.

Once the car then stops hunting it idles around 1100/1200rpm and does so for an extended time until it finally idles at 750ish rpm.

 

I am after advice as to why this might be and if there is anything obvious to check before the weekend and it is plugged into my friends laptop.

 

Any help is appreciated

Many Thanks Nick

[Jon_vr6 1]

Does it misfire whilst driving the car?

[mic_VR 3]

Blue smoke is never good, that's burning oil. I'd hate to start suggesting things like piston rings, valve guides, headgasket etc but I'd suggest getting it looked at sooner rather than later.

 

What's your PCV valve like? And how blue is the smoke? Does it burn blue under load?

[Nick 17 10]

Recent update - I have closely had chance to have a look at the car and these are the symptoms;

 

On start up splutters and struggles to find idle point,

Car then runs and sounds like the idle will not settle,

On pressing the accelerator the engine initially dips as if to die and then picks up

- as this happens the car will mist (BLACK) smoke not blue.

 

This will happen if the car is hot or cold appears to make no difference.

 

I have tried disconnecting the maf set up and no air leaks appear present.

 

The symptom has appeared a month after replacing the thermostat housing.

 

Would one of the temp sensors in the housing be responsible for the rough start up and running?

 

Many thanks, Nick.

[vw rule 19]

Hello there,

 

could possibly be over fueling a little as black smoke is fuel,

and blue smoke is normally oil.

Could be the coolant temp switch is playing up and causing too much fuel to be injected,

which can give the symptom you are talking of.

 

 

Si

[Ray1965 10]

You could also check the air filter is clear.

fuel injection system.

Faulty injector.

spark plugs. (will be black in colour if running rich).

Good luck keep us posted.

[Gti_Jamo 10]

Disconnect the connector for the lambda sensor located on the bracket secured to the top of the rear engine mount then see if it runs better, if it does then it's likely to be faulty, worth a shot anyway. Had a similar issue with my mk3 vr a year or so ago.

[Nick 17 10]

The issue has been resolved today.

Failure of blue temperature sensor

luckily a cheap fix and sorted quickly

Thanks a lot for your help people :)