CR 170 strange issue DPF ?

[Mark1316]

Guys and Girls I have come across a strange intermittent issue ? Car ticks over at about 750 rpm most times  and sounds like a sewing machine . Sometimes it ticks over at 1000/1100 rpm and a bit lumpy . It can stay like this for days and then go back to normal for a few days and sometime weeks . I have run VCDS and does not report any faults from DPF ?.

I have also noticed that the engine does not seem hot even after a 2 hr drive ? The water temp shows around 90 degree C tho .

Does this sound like a Sensor issue ?

[PipH]

It sounds like your engine is trying to regen the DPF.

 

If you went for a drive 10 - 20 miles, the DPF should be able to regen & tickover would be back to normal.

 

Suspect you do a lot of short journeys.

 

[Mark1316]

Thanks for the reply . My car does 30 min drive each way between home and work 5 days a week . When its playing up I do the same drive in 3rd or 4th gear and above 2500 rpm and does not clear it ? The engine being cold to touch give me some worry ? I have never had a car that the engine is cool to the touch after a 2 hr drive ?

 

If the car was trying to do a regen would there not be an error or warning through vcds?

 

[PipH]

A 30 min drive should easily regen the DPF, as long as you get to around 40MPH for a few miles.

 

Don't get hung up on revs, as long as the engine is revving over 1800RPM it will be fine.

 

Do you have a DSG ?

 

No error when trying to do a regen, it's just doing what it should be doing.

Edited 22 August, 2020 by PipH

[Mark1316]

No it's a 6 speed manual Vrs ltd .

I will get Vcds plugged in today and see if it can read the soot levels it's showing ? I'm just hitting YouTube to see if I can find where to look lol 

[Mark1316]

I could be barking up the wrong tree with this issue ? But when the tick over is high I can smell fuel inside the car . 

[PipH]

When the engine is trying to regen the DPF it injects extra fuel late in the exhaust cycle which doesn't get burnt in the cylinder, but goes into the DPF to heat it up & burn off the soot.

You shouldn't be able to smell this in the car.

 

I think that maybe you have a leak somewhere between the exhaust manifold & DPF which is affecting the regens as well as leaking into the engine bay/ cabin.

 

Have a good look around this area for black soot.

[J.R.]

Where exactly are you feeling when you say the engine is cool to the touch?

[Mark1316]

18 hours ago, J.R. said:

Where exactly are you feeling when you say the engine is cool to the touch?

Along the top under the engine cover .

[Updown789]

Possible failed thermostat not allowing car to get up to temperature. DPF regen will only commence over a certain coolant temp

[Mark1316]

53 minutes ago, Updown789 said:

Possible failed thermostat not allowing car to get up to temperature. DPF regen will only commence over a certain coolant temp

 

It shows 90 on the gauge and when I check on the torque app it says 84 so its quite close to the correct temp. Heaters all blast out hot air once up at 90 ?

[Ecomatt]

How long have you had the car and has it always done it?

Does VCDS show you the ash levels etc.

[Jevpls]

High idle rpm could be because of hot weather & AC too but there shouldn't be smell from fuel.