75 TDI running rich?

[Damian Bond]

Hi, I’m wondering if anyone can help me get an idea what would cause my A2 to run rich?

Starting has never been a problem but when left idling on the drive for roughly 5 minutes there’s soot on the floor! Also under acceleration at night I can see a trail of smoke behind me lit up my the car behinds lights.

I know the EGR needs replacing if that’s relevant and my MPG used to be 65 and now lucky if I get 55. After having my cambelt changed I asked the guy at the garage what could be the problem and without having a look said it’s likely the fuel injectors (£300 for each). Seems a bit drastic as a starting point. The cars done 152,000 miles and is on a 02 plate.

If anyone could point me in a possible right direction to start looking I’d really appreciate it.
Thanks Damian

 

[Howey]

The coolant temp sensor would be the first item i would look at, see what readings its supplying the ecu with. Also check injector correction values and torsion value

 

[Damian Bond]

The coolant temp sensor would be the first item i would look at, see what readings its supplying the ecu with. Also check injector correction values and torsion value

Thanks my A2 never get up to 90 degrees do you think this could be related? I’ll replace the thermostat anyway.

 

[Howey]

Thanks my A2 never get up to 90 degrees do you think this could be related? I’ll replace the thermostat anyway.

Yeah it wont help thats for sure, and if its not had a cts defo worth doing at same time!
Theres two bleed screws one on top of rad other down side of webasto

Think winter causes mpg to drop but not black smoking, presume its performance is uneffected with no boost leaks?

 

[Damian Bond]

Yeah it wont help thats for sure, and if its not had a cts defo worth doing at same time!
Theres two bleed screws one on top of rad other down side of webasto

Think winter causes mpg to drop but not black smoking, presume its performance is uneffected with no boost leaks?

Performance is faultless and no boost leaks that I can tell. I’m not the most experienced mechanic to say the least ?! Can I ask what a cts is.
Excuse my ignorance
Thanks Damian

 

[Howey]

Cts= coolant temperature sensor

 

[sunsurfer]

Thanks my A2 never get up to 90 degrees do you think this could be related? I’ll replace the thermostat anyway.

If the ecu thinks the engine is not up to temperature (faulty thermostat and/or temperature sensor) it will keep the engine running rich.
Mine was fixed by a new thermostat and makes sense to do both thermostat and sensor.

 

[kp 115]

Hi, I’m wondering if anyone can help me get an idea what would cause my A2 to run rich?

Starting has never been a problem but when left idling on the drive for roughly 5 minutes there’s soot on the floor! Also under acceleration at night I can see a trail of smoke behind me lit up my the car behinds lights.

I know the EGR needs replacing if that’s relevant and my MPG used to be 65 and now lucky if I get 55. After having my cambelt changed I asked the guy at the garage what could be the problem and without having a look said it’s likely the fuel injectors (£300 for each). Seems a bit drastic as a starting point. The cars done 152,000 miles and is on a 02 plate.

If anyone could point me in a possible right direction to start looking I’d really appreciate it.
Thanks Damian

Has the air filter been replaced ?
I also run STP Diesel Injector cleaner through regularly to good effect, along with good quality fuel (Shell)

 

[Damian Bond]

If the ecu thinks the engine is not up to temperature (faulty thermostat and/or temperature sensor) it will keep the engine running rich.
Mine was fixed by a new thermostat and makes sense to do both thermostat and sensor.

Thanks very much I’ll get that looked at asap.

 

[Damian Bond]

Has the air filter been replaced ?
I also run STP Diesel Injector cleaner through regularly to good effect, along with good quality fuel (Shell)

I changed the filter but no joy. I regularly put in BP ultimate and one of those bottles once in a blue moon. I filled the car up with Tesco diesel a few weeks back and you can definitely tell the difference! Thanks for the reply

 

[kp 115]

I changed the filter but no joy. I regularly put in BP ultimate and one of those bottles once in a blue moon. I filled the car up with Tesco diesel a few weeks back and you can definitely tell the difference! Thanks for the reply

How long have you had the car?
Judging by your age I’d say not long, try running it on a fast dual carriageway at high revs in the lower gears before changing up this will clear a lot of the rubbish out (Italian tune up)

 

[Damian Bond]

How long have you had the car?
Judging by your age I’d say not long, try running it on a fast dual carriageway at high revs in the lower gears before changing up this will clear a lot of the rubbish out (Italian tune up)

I bought it from a family friend who really looked after it from 2003 to September last year when I bought it. I’ve done 13,000 miles since then. I’ll give it a go thanks ?

 

[audifan]

Short commutes are the worst, especially this time of year. The car barely gets up to operating temperature. Everything needs to get hot to help burn off the exhaust residue and keep the cat working well.

As you have already been advised by Keith, a good Italian tune up will help as will a regular long trip. Certainly either fuel additives or premium fuel will also help along with regular maintenance.

 

[Alfie Noakes]

For what it's worth I have a 90TDI and it has always smoked when I put my foot down, exactly the way you have said. It warms up to 90deg in about 5-7 miles.
On a motorway the best I can get is 60mpg at 60mph. Around town on short journeys at the moment I'm getting 41mpg. I bought the car with 24k in 2008 and its now done about 160k.

I get about 10mpg better in the summer. The mpg has got less as the miles go up.

Having replaced lots of stuff over the years I have come to the opinion that it's probably a combination of general wear and tear and lots of little things being slightly off. The previous owner, a friend, had it from new, had it mapped by AMD in Oxford to 115 bhp.

 

[Robin_Cox]

Hi, I’m wondering if anyone can help me get an idea what would cause my A2 to run rich?

Starting has never been a problem but when left idling on the drive for roughly 5 minutes there’s soot on the floor! Also under acceleration at night I can see a trail of smoke behind me lit up my the car behinds lights.

I know the EGR needs replacing if that’s relevant and my MPG used to be 65 and now lucky if I get 55. After having my cambelt changed I asked the guy at the garage what could be the problem and without having a look said it’s likely the fuel injectors (£300 for each). Seems a bit drastic as a starting point. The cars done 152,000 miles and is on a 02 plate.

If anyone could point me in a possible right direction to start looking I’d really appreciate it.
Thanks Damian

£300 each?

Only if you buy them brand new in a solid gold presentation box.

The normal AMF / BHC injectors can be obtained for tens of quid for a set of three second-hand needing to be given a bit of work. They are built like brick privies unless really badly abused - send them away for a test, clean and replacement of o-rings followed by re-test (it cost me less than £200 including shipping for 6 to be done at Darwen Diesels) - then get them put in with a proper set up of the adjusters (and a new loom in my case) and it makes a huge difference - a near 300k engine running like a slightly clattery sewing machine (vast improvement on how it was before they were done). If serious repairs need doing then it is >100 quid each for something that is effectively new when it is done but that is still a hell of a lot cheaper than "new" new prices.

If you've got another vehicle - you could even get your own ones cleaned and back to full working order relatively cheaply. Remember also that the bolts that hold the injectors and rockers in also need to be replaced, and the rocker cover lid can be a bit of a pain to seal properly even if brand new - there is a specific order and torque specification for the approximately 279 bolts that secure it that needs to be followed exactly and I'm not convinced this is done by many mechanics.

If you can't get hold of suitable injectors here or on Ebay, try contacting someone like Darwen Diesels direct in case they have something suitable refurbished on the shelf.

Diesel Fuel Injection Components, Parts and Spares - Darwen Diesels Ltd

Diesel Fuel Injection Components, Parts and Spares

www.darwendiesels.com

Obviously other diesel injector places exist, but I was recommended them by @depronman here and I have been delighted with the outcome.

 

[Damian Bond]

£300 each?

Only if you buy them brand new in a solid gold presentation box.

The normal AMF / BHC injectors can be obtained for tens of quid for a set of three second-hand needing to be given a bit of work. They are built like brick privies unless really badly abused - send them away for a test, clean and replacement of o-rings followed by re-test (it cost me less than £200 including shipping for 6 to be done at Darwen Diesels) - then get them put in with a proper set up of the adjusters (and a new loom in my case) and it makes a huge difference - a near 300k engine running like a slightly clattery sewing machine (vast improvement on how it was before they were done). If serious repairs need doing then it is >100 quid each for something that is effectively new when it is done but that is still a hell of a lot cheaper than "new" new prices.

If you've got another vehicle - you could even get your own ones cleaned and back to full working order relatively cheaply. Remember also that the bolts that hold the injectors and rockers in also need to be replaced, and the rocker cover lid can be a bit of a pain to seal properly even if brand new - there is a specific order and torque specification for the approximately 279 bolts that secure it that needs to be followed exactly and I'm not convinced this is done by many mechanics.

If you can't get hold of suitable injectors here or on Ebay, try contacting someone like Darwen Diesels direct in case they have something suitable refurbished on the shelf.

Diesel Fuel Injection Components, Parts and Spares - Darwen Diesels Ltd

Diesel Fuel Injection Components, Parts and Spares

www.darwendiesels.com

Obviously other diesel injector places exist, but I was recommended them by @depronman here and I have been delighted with the outcome.

I’ll do some more research but I’ll probably get my local independent VAG specialist to fix it for me. Thank you for your help!

 

[Damian Bond]

For what it's worth I have a 90TDI and it has always smoked when I put my foot down, exactly the way you have said. It warms up to 90deg in about 5-7 miles.
On a motorway the best I can get is 60mpg at 60mph. Around town on short journeys at the moment I'm getting 41mpg. I bought the car with 24k in 2008 and its now done about 160k.

I get about 10mpg better in the summer. The mpg has got less as the miles go up.

Having replaced lots of stuff over the years I have come to the opinion that it's probably a combination of general wear and tear and lots of little things being slightly off. The previous owner, a friend, had it from new, had it mapped by AMD in Oxford to 115 bhp.

Mine won’t get up to 90 degrees except this one steep hill on a dual carriageway. As @sunsurfer says I’ll get my thermostat and temperature sensor replaced. These cars are clearly something special especially compared to my previous car a 2003 rover 25. I’ll replace everything on it like triggers broom until it’s a brand new car if I have to! ?

 

[donp38]

I would suggest thermostat first..

 

[Little Dog]

Feels like the car thinks it's cold or it is cold. Thinks, new temperature sender; is, new thermostat. Then drive it; I've never achieved 60 mpg from my 75 bought new but my induction is as clean as a whistle and for a car with very little power it cracks on nicely; could be worth checking the induction system too for carbon plus oil deposits.

 

[audifan]

There is a difference between white smoke and black smoke. All diesels produce a little smoke regardless - hence the governments deeming them the transport of Satan.
You could be getting less MPG for various reasons including mechanical / electrical. You could just be driving the car differently, the weather, a bad service item, a fuel leak etc,etc.......