About to buy Audi A4 - Questions
- Thread starter psd99
- Start date
The Diesel Particulate Filter can cause a problem.
I'm sure someone will explain exactly what it does but AFAIK it seems to re-burn the exhaust gases to reduce pollution. In order to do this it needs to get very hot.
If you do short journeys it doesn't get hot enough so can become clogged. This is where the problems occur. The car will realise the filter is getting clogged and try to compensate which can cause high idle, poor MPG and all sorts of other stuff. I've people say you need to drive the car every couple of weeks above 4K for about half an hour to help keep things happy (so a motorway or dual carriageway journey every couple of weeks)
Some have had success with remove, clean, refit. Others once its started playing up it won't be happy until its been replaced. I think its about £1200 for the A4 DPF - i think.
However, its a fairly simple task of remove, cut open, gut, weld up, refit, remap and happy days. Remapping is plugging in a laptop and how the engine is managed. You can get recommendations from Audi Sport forum on who to use. Some places offer to do the job for a few hundred pounds. Mine was more because I wanted it removed completely plus the egr removed completed (not just turned off) and had a bit of a service whilst in the garage. I hesitate to say it but with the DPF removed the car actually sounds almost cool, the turbo whistle is so loud you can't hear the clatter clatter clatter diesel engine. It sounds deeper and if I could afford a Miltek system I think it would sound pretty good, for a diesel.
I'm waiting on some Samco hoses to re-plumb the coolant system so I can remove the EGR cooler. EGR (Exhaust Gas Recirculation valve) sends some exhaust gases back round into the inlet, seems a shocking idea to me but another emmissions issue - it too can clog up and cause problems (you sometimes hear a sneezing sound but it doesn't sound cool like Dump Valve
). You can have it turned off or removed completed and replaced with a pipe - mines from Darkside Developments who were very helpful even though the pipe had never been fitted to a B7. Before the gases get to the inlet, it passes through a metal tube with a coolant jacket around it. This can leak sending coolant into the exhaust system - my car has been losing coolant for ages and its either a cracked head or fingers crossed its the EGR cooler. If the head is cracked my only advice is buy a BMW 
my car also has this really odd noise which sounds like someone blowing over a bottle (if you know what that sounds like) but it only does it under load, on gas its one tone, off gas its another tone. I think (hope) its where the cooler has been blanked and as the little valve opens once hot its blowing exhaust gas over the bunged up port and causing the noise. Pooped myself at first thinking it was the turbo failing but the turbo is quite easy to get to and waggling the shaft it feels in good shape.
Or just buy a petrol
I posted a pic of my car in the other Audi thread - post 168 I think. Nothing special mind.
I'm sure someone will explain exactly what it does but AFAIK it seems to re-burn the exhaust gases to reduce pollution. In order to do this it needs to get very hot.
If you do short journeys it doesn't get hot enough so can become clogged. This is where the problems occur. The car will realise the filter is getting clogged and try to compensate which can cause high idle, poor MPG and all sorts of other stuff. I've people say you need to drive the car every couple of weeks above 4K for about half an hour to help keep things happy (so a motorway or dual carriageway journey every couple of weeks)
Some have had success with remove, clean, refit. Others once its started playing up it won't be happy until its been replaced. I think its about £1200 for the A4 DPF - i think.
However, its a fairly simple task of remove, cut open, gut, weld up, refit, remap and happy days. Remapping is plugging in a laptop and how the engine is managed. You can get recommendations from Audi Sport forum on who to use. Some places offer to do the job for a few hundred pounds. Mine was more because I wanted it removed completely plus the egr removed completed (not just turned off) and had a bit of a service whilst in the garage. I hesitate to say it but with the DPF removed the car actually sounds almost cool, the turbo whistle is so loud you can't hear the clatter clatter clatter diesel engine. It sounds deeper and if I could afford a Miltek system I think it would sound pretty good, for a diesel.
I'm waiting on some Samco hoses to re-plumb the coolant system so I can remove the EGR cooler. EGR (Exhaust Gas Recirculation valve) sends some exhaust gases back round into the inlet, seems a shocking idea to me but another emmissions issue - it too can clog up and cause problems (you sometimes hear a sneezing sound but it doesn't sound cool like Dump Valve
). You can have it turned off or removed completed and replaced with a pipe - mines from Darkside Developments who were very helpful even though the pipe had never been fitted to a B7. Before the gases get to the inlet, it passes through a metal tube with a coolant jacket around it. This can leak sending coolant into the exhaust system - my car has been losing coolant for ages and its either a cracked head or fingers crossed its the EGR cooler. If the head is cracked my only advice is buy a BMW my car also has this really odd noise which sounds like someone blowing over a bottle (if you know what that sounds like) but it only does it under load, on gas its one tone, off gas its another tone. I think (hope) its where the cooler has been blanked and as the little valve opens once hot its blowing exhaust gas over the bunged up port and causing the noise. Pooped myself at first thinking it was the turbo failing but the turbo is quite easy to get to and waggling the shaft it feels in good shape. Or just buy a petrol
I posted a pic of my car in the other Audi thread - post 168 I think. Nothing special mind.
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I think mine on a forecourt would probably be up for £10K. The one I linked to on PH is up for the same with 30K less - only thing I would say is the drivers seat leather looks a bit tired.
To be honest with £10K, I'd go for the petrol.
EDIT - http://www.pistonheads.com/sales/3955278.htm
To be honest with £10K, I'd go for the petrol.
EDIT - http://www.pistonheads.com/sales/3955278.htm
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which link mate can't see it now?
Regarding the DPF, it's a steady drive at around 60 MPH, no need to trash the engine while doing it.
EGR can be blocked off/removed for better performance but it may need recoding to account for the change. Offers better performance but less MPG and worse emissions.
Someone said above the 140 doesn't have DPF but I have a 2005 A4 (B7) 2.0 140 and I'm sure mine does :S
EGR can be blocked off/removed for better performance but it may need recoding to account for the change. Offers better performance but less MPG and worse emissions.
Someone said above the 140 doesn't have DPF but I have a 2005 A4 (B7) 2.0 140 and I'm sure mine does :S
I don't think the 140 has a DPF. I'll have a look under the bonnet of mums later and check.
Maybe the worse MPG with EGR removed is from the mapping? I've had mine taken off and had a couple of PSI added to the boost and its no worse than before. Apparently it does make the engine run a bit hotter but I'm not sure why.
Maybe the worse MPG with EGR removed is from the mapping? I've had mine taken off and had a couple of PSI added to the boost and its no worse than before. Apparently it does make the engine run a bit hotter but I'm not sure why.