Had a long motorway trip yesterday (no engine issues, all was well). Got in the car, started it, drove down the road, felt a bit sluggish. turned onto a main road, accelerated lightly, 2rd, 3rd, then no power and engine sounded rough, like it was running on 3 cylinders and white smoke coming out the exhaust in quite a good quantity.

Pulled over to the side of the road, rev'd it gently - even more white white smoke, engine still sounding like it was a cylinder short. Turned it off, waited 30 seconds, turned it back on still sounded wrong, so I turned it off and walked back to my brothers house - just around the corner.

Came back to the car about 45 minutes later, and it started fine and drove back to my brothers without an issue.

This has happened once before a few Easters back - almost identical, apart from I was at my parents that time. At the time I posted about it and one other guy responded saying his car had done this a few times but wasn't really sure of the cause. At the time someone suggested a sticky injector, iirc. I was hoping this was a one-off for my car (must be a good 60-70k ago), but maybe not......

Any ideas? 110TDI now with 205k on the clock.

It could possibly be the egr valve stuck open so it would be overfueling causing the white smoke or sticky veins on the turbo possibly drop the egr valve off tomorrow and give it a clean if that doesent work do a search on the forum for mr muscle turbo treatment

If it sounds like you're only running on 3 cylinders... I'd suspect that may actually be the case.

However...

...If this goes away after it being turned off a while - Possibility the needle lift sensor on injector 3 is faulty.

My guess is injector #3 sticking open. I think the needle lift sensor itself is OK, because you didn't mention getting the EML coming on.

At 205k, it's worth getting the injectors serviced.

EGR already bypassed. I'll do another Mr Muscle treatment.

No EML came on, but sadly I don't have a laptop with VAGCOM on it for me to check to see if any fault codes are logged. Last time this happened, I don't think anything specific was logged.

How much is getting the injectors serviced likely to cost me? Also, for the uneducated, what is the needle lift sensor?

Thanks all :-)

Just buy another set of injectors, and some crush washers, cheap 50 quid total if you shop around.

The needle lift sensor is an integral part of injector #3. If you look at the injector, you will see it is taller than the others and has a wire coming out of it. The sensor comprises a rod and pickup coil. It senses when the needle lifts and indirectly the SOI at the pump. The system is very tolerant of degrading performance but injector #3 is the weak point.

Getting the injectors serviced with new nozzles, should cost about £100 for all 4.

Some companies offer an exchange option that may be more convenient http://www.dieselbob.co.uk/orderinjectors_skoda.aspx but that is more expensive.

EGR already bypassed. I'll do another Mr Muscle treatment.

No EML came on, but sadly I don't have a laptop with VAGCOM on it for me to check to see if any fault codes are logged. Last time this happened, I don't think anything specific was logged.

How much is getting the injectors serviced likely to cost me? Also, for the uneducated, what is the needle lift sensor?

Thanks all :-)

Basically the needle lift sender tells the ecu when injector three is injecting fuel. Combine this with G28 (crank sensor) and the ecu knows where and when to inject on the other three cylinders.

Obviously if one, or the other start to go iffy then you get all sorts of mayhem and poor running with misfires, low power, and limp mode and/or white smoke.

First bet would be to check any fault codes. After that, if neither point the finger at one of them... Start with checking the resistance of the needle lift sensor. Should be between 80 and 120 ohms. If it's not, then it's toast and you're likely looking at replacing all 4 injectors as a precautionary measure (not to mention not many people sell just injector 3!)

Then, check the bell housing for the G28 sensor. Obviously because it's in a vulnerable position it's subject to all sorts of crud, not to mention water, etc. Can easily get dirty or wet and cause a similar fault. Check it, clean it, put some dielectric grease on the plug before you plug it back in. ***This should be done as a preventative maintenance item!***

Any more help you need? Give me a shout.

Any chance of a picture of the crankcase/G28 sensor? Will see if I can drum up a laptop with a serial port for my old vagcom cable.

Cheers :-)

Any chance of a picture of the crankcase/G28 sensor? Will see if I can drum up a laptop with a serial port for my old vagcom cable.

Cheers :-)

http://audi.workshop-manuals.com/a3/index.php?id=2101 - item 10.

I'd go out and take a picture but i'm _meant_ to be working...

Can take a piccy at lunch though.

Thanks all... guess I had better look into getting my injectors serviced.

Just had a chance to scan the car. The onyl code logged was the normal overboost one

VAG-COM Version: Release 303.1

Control Module Part Number: 038 906 012 CL 
 Component and/or Version: 0000SG 3316 
          Software Coding: 00002
           Work Shop Code: WSC 31480
          Additional Info: TMBGP21U512486883     VWZ7Z0Y3096563
1 Faults Found:
17965 - Charge Pressure Control: Positive Deviation
       P1557 - 35-00 - -

Not had a chance to do anything, but it just happened again. Was a few hundred yards from my home, in the righthand lane of a pair of lanes to go straight on at the traffic lights. You have to filter in pretty quickly, so the lights went green, I accelerated hard-ish (enough to make the sunglasses fall out from out of the cubby hole under the stereo), and then bammmmm, no power and white smoke. Filtered in, and then had to limp over the bridge and make it to a carpark not very far away when I could turn it off and wait.

It was still generating good white smoke when I got t the carpark - tickover seemed to sound not too bad, but there was virtually no power if I touched the accelerator. Anyway, I turned it off and waited 20 minutes and then it started and was fine.

Of the three times this has happened, I have always been very close to "home", so I am wondering if it is brought on my something else as well - cold engine, or glowplug heaters, or something....?

I'll give Poole Diesel a call tomorrow morning and see how much they might charge to service/exchange my injectors for me.

If it went into limp the ECU will have a fault code logged, which will point you in the right direction to repair.

Edited 16 December, 201213 yr by pauldazzle

Just noticed it's mbames, you'll already know it'll have code logged.

Pretty sure there won't be any codes logged - or nothing other than my semi-regular overboost fault. Will check tomorrow - to wet and horrible to want to want down to the garage with a laptop tonight!

That's odd, always thought that for the ecu to into limp it had to of seen a fault?

Not sure, I don't always clear my overboost faults, but I suspect that if there any faults logged that will be it and nothing else :-( I can't see why an overboost fault would cause it to start making white (diesel-ly) smoke... and running really rough, rather than normal lack of acceleration.

Over boost stays logged but limp goes after a ignition cycle.

Fwiw have you tried a high quality injector cleaner matt?

Might sort it out long enough to get your injectors exchanged or properly cleaned up.

The old engines were known for spray patterns going off and coating the cylinder walls with derv from anywhere above 80k miles

What's the timing like? It would be interesting if you could check the timing with VCDS whilst it's having the problem.

What is the best way of checking the timing? I have never done this. Normally I don't carry a laptop in the car, but I might stick an old one in for the next time time happens.... although I would feel rather guilty with the engine sitting there pumping out white exhaust fumes while I faff about with a laptop.

What classes as a high quality injector cleaner? It gets a helping of red-ex now and then.

You need either full fat vcds or vcds lite registered. There is a how to on the Ross tech wiki, you do need the coolant temp to be over 80 degrees for it to work properly though.

When you run the tri timing checker you get a graph and you are looking for the timing to be within the upper and lower limits, preferably within the upper half of the graph. Also the spots generated should be well clustered together.

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I have full fat registered vagcom (old version).

I think that might be a problem, wrt 80+ deg coolant temp - it seems that this issue only ever happens when the car is cold (only been running for a minute or two).

I would maybe start by checking the timing when the engine is up to temperature, just to see what it is like.

I can't remember what the implication is of trying to check the timing when the coolant temp is too low. The graph plots fuel temp against timing and you need a fuel temp of 100-150 to sit in the middle of the x axis. There may be an explanation on the the ross tech site.

Might be worth checking the injector harness connctions as it's not unheard of for them to make poor contact when cold. Easy job to do, rocker cover off then remove & widen each connector & refit.

Forte injector cleaner would be my bet matthew.

If you're around wilts give me a poke if you've still got my number and I'll try and sort you out with a VCDS scan from a new full fat version.

I take it on the turbo, you've tried the Mr Muscle clean too?