The chip upgrade is good value - Honest Ron also does one which is as good if not as powerful. The engine in the CDT and CDTi was the first fit of the BMW diesel used in the 320d -330d. It's detuned and doesn't have either the variable vane geometry turbo or twin turbos fitted to the BMW range. The 75 in deisel form is 2 tonne of car and thats heavy. The chip upgrade - if its a decent one will give more power over the whole driving range - this can make for more relaxed driving, better acceleration AND improved fuel economy.

Faults to watch for are:

1. Fuel pumps - there are 2 and the back one can fail - this puts pressure o the high pressure pump in the engine bay and this fails. To check the pumps - start the car and put your head down (needs less than a 1/4 tank of fuel) on the back seat (drivers side) you should hear a humming/slightly whistly sound. In the engine bay the pump sits behind the fuel pump - it should whistle too. I replaced both after a failure and its a relatively simple job - particularly the engine bay pump, which took about 20 minutes - this is the vital pump - which gets /keeps you going. Total cost of pumps EBay £160.

best advice is - keep the fuel level over a 1/4 tank - which stops the tank pump coming under pressure.

2. MAF meters - mine hasn't gone yet - a simple fix though and prices are £35-£120 on EBay

3. Front springs - were weak and should have been upgraded on a recall - if not £70=-100 for a pair

4. The firwall well at the back of the engine bay - can fill with water and take the ECU which lives there out. Clean it regularly - many on=wners take the drain fittings out all together

Living with it? It is a superb motorway muncher - stable, comfortablle quiet and refined. Climate control is better than BMWs and its smooth. Round twisties - the chassis will outperform the engine. Braking's good - it is a great car 160k miles not one rattle or trim failure and panel fit is spot on. Its a lot of car for not a lot of moneyand build quality is A1. It's also one of the easierst cars I've worked on.

Oh and if you like any bass in your hi-fi at all - you wont get any out of the standard harmony unit. Solutions are to get the dash insert MG fitting and put another head unit in or fit a bass unit - I did the latter - which cost £40 and it's been a huge improvement.

I'd recommend Event Tyres - I got 18k out of the fronts and they were still legal when I replaced them - a meanie prepared to live with the fact the handling was going off - or doing town driving may have pushed on to 20k.

I've done 50k+ in this motor and I'd recommend it to anyone,

Old thread. Chipping can be OK to get a bit of extra spice out of a mildly set up engine, but some of the claims are a bit suspect.

In 1st gear, I was driving slowly up a very steep hill, dropped out of turbo range, and stalled and my foot flat to the floor. We had it chipped, went back to the same hill, and floored it in the same place, at the same speed. The difference was unbelievable, the front of the car lifted...

Turbos are feedback loops. They don't spool because the engine fuelling is restricted at very low speed to protect the DMF and clutch. It's better to let the engine stall than destroy an expensive component. Chipping promises the earth. It's easy to get more power but lets be clear about this; claims about 15% improved fuel economy are total rubbish, unless you were purposely driving in a unnecessarily low gears beforehand.

Edited by unthrottled on 26/03/2012 at 22:45