Hi Guys,

I was hoping i could pick someones brain, either someone who's had a similar issue or just know their Audi's

Ive got a 63 plate Audi A1 1.6 Diesel, S Line Manual, From a cold start it has some issues idling at 1k and seems like the engine is starved of air as it shakes a fair bit and a lot of the vibrations come through to the clutch, at this point it spits out plumes of white smoke, stinks like hell, toxic smell.

Once driven after 5 minutes the smoke clears and the car runs a little smoother but still chokes a little when going at low speed.

If i pull over and switch off, even after 30 minutes it starts fine and idles nicely but leave it over night and its back to square one.

Ive put in DPF cleaner in the fuel system, car hadnt been serviced since 7k and now its on 42k so ive serviced it twice within a week, the first service i used an engine cleaner, none of this has helped even though i took it from London to brighton and back today trying to get it to regen which didnt happen.

im thinking to remove the DPF altogether and delete from ECU but i dont even know if that is the cause, there are no lights on at all on the dash. Turbo works fine and the car shifts and goes quick as it should.

Any ideas would be greatly appreciated...

 

It could be a coolant temp sensor giving the wrong temp reading for cold starts.. Usually when they run fine when they're at operating temp, it's a coolant temperature sensor telling the ECU that it is at operating temperature even when it's cold. The fuel/air mix needed to start cold needs to be a bit rich (more fuel). If the mix is off, it may still run but runs rough.

However, white/blue smoke is usually oil smoke. It could be leaking into the intake and causing it to run rough until the oil is burned off after a few minutes of running.

 

Both those seem like it could be the issue, especially the oil leaking, I'll see if a mechanic can see any leaks, thanks for the reply Dave.

 

Just to update, i took it to Audi Wimbledon today for their £60 diagnostic service, not very helpful, i dont think they even turned the car on, simply plugged in for diagnostic, its come up with a throttle valve issue and they want me to fix that before they will look at the smoke issue. So that would be another £60 diagnostic after a £550 throttle valve replacement.

I asked if i buy just the throttle valve and replace it myself do i need to code it, they said they dont know, does anyone know if i can just do a straight swap of the throttle valve without the need to code the part? if it needs to be coded then im obviously going to be stung for something they cant guarantee that is the problem. Might try and clean.

really disappointed with their service, the technician that worked on the car said there was white smoke on the report (the white smoke i reported that is), i interjected and said "did you see the white smoke" he said no. so basically they didnt even run up the car. literally just plugged it in.

 

Unfortunately when replacing the throttle body (valve) you do have to do "adaptation" to the ECU with it. Suggestion. These cars are OBDII cars also. You can get an OBD code reader from an Automotive Store for under $50US and pull the majority of the Engine Error codes. I'd get one and pull the codes and see if the Throttle Body is actually reporting an issue. I don't call them the "stealer.....er....dealer" for nothing.

 

Yeah no kidding, I removed the throttle valve myself, took 10 minutes and I'm no mechanic, 3 bolts and some other minor bits, they wanted £260 labour for that, it has a lot of carbon build up, I've cleaned it with petrol, also removed the plastic thing that had the injectors going into it, the manifold maybe? That was a little trickier, used brake cleaner and my jet wash but that was a pain to clean properly, I don't know if it's like placebo effect but it seems to run a little faster but still smokes, going to attempt to remove the Egr and give that a clean over the next few days, hopefully I can fix it and it might help someone else out. Good shout about the obd, will pick one up. Thanks

 

Sounds like a plan. I'd drive it a bit and see if the smoke goes away after it burns some more of the crap out of the system. The crud build up in the throttle valve could have been restricting airflow which reduces performance. Also, all of these engines these days run a PCV System (Positive Crankcase Ventilation) which will pull crankcase vapors (oil vapors) into the intake to be burned. There is a diaphragm valve that will close when the engine is at idle (no throttle input) when intake vacuum is it's highest. If that valve malfunctions, it will pull in LOTS of oil vapor, and sometimes OIL into the intake causing excessive smoke if too much oil is pulled in over time. It will pool in the intake's lower portions. Once those fill up, it will start to get pulled directly into the cylinders, burning with the fuel making more smoke than it really should. To test this, crank the engine and while it's idling, loosen the oil filler cap. Gently and slowly lift up on it and if you can feel it being sucked back down onto the opening, the PCV valve is defective and needs replacing. I've replaced 2 on my A8 over the past 5 years. The rubber diaphragms rupture on them allowing excessive airflow from the crankcase into the intake. I removed the intake from my 4.2L engine last year to clean things up while I had the cams out changing the chain tensioners. I set the intake on the bench and it tipped over onto one side. Oil began to pour out of it. At least half a quart. Driving it with the defective PVC valves for extended amounts of time had to be the culprit.

 

ive heard that PVC mentioned before, not sure where it is but will have a look.

I have managed to remove the EGR with a friends help, what a pain that was, exhaust had to come off, pipes, coolant leaked, even when we had it removed it still would not come out as the drive shaft and gearbox were in the way, had to remove alloy and get it out through the arch.

theres a bit that needs to close and open and thats welded stuck it seems from the gunk build up, i think its beyond fixing but will try and clean it. might be worth just getting the egr valve replaced but i cant tell if the rest is ok or not and that bit is impossible to clean.

Could try my luck and get just the valve from german and swedish, and also ask about the PVC, might be called something else as its not on their site, my other issue now is, my mate is over here on holiday so i wont be able to get to whole unit in time before he leaves the country and he done 70 % of the work so i dont think ill be able to put it back together all by myself, im quite sure ill end up with some spare parts, i suppose i could ebay those extra bits left over lol

ive added some photos,

 

The PCV Valve assembly looks something like this. https://www.google.com/search?q=Audi...&bih=979&dpr=1

 

Ok thanks, this EGR is not repairable, its pretty bad, im picking a new one up tomorrow, not OEM but should do the trick, hopefully no ECU coding issues to tackle, do you think, knowing that the EGR is for sure an issue, that i should still change the PCV? do they break together?

i suppose i could replace the EGR and if its still dodgy then also replace the PCV, or would you recommend to just to do both?