Hi,

I have a 2005 TD4 that developed a problem of when cruising at around 2.5-3K revs it would suddenly feel like the engine stops for a split second and also when starting from cold it would start on tickover but when you pressed the accelerator pedal the revs wouldnt increase and you had to feather the pedal to get the revs up, once warm it would rev ok, after reading similar problems on here I dissconected the MAF and started the engine from cold, the engine started ok and revved ok but sounded like a can of spanners rattling and I got lots of smoke out of the exhaust, is this normal when the MAF is disconected? and because the engine revved ok does that indicate a faulty MAF? when I re-connected the MAF the noise and smoke went but the lack of revving until warm came back.

Thanks for reading this long winded post and appreciate any advice.

Thanks

Les

The engine may well sound harsher when you disconnect an underfuelling Maf but any smoke should eventually clear after driving for a while provided there isn't another fault.

Hi and thanks for the reply,

I didnt drive the car so dont know if the smoke would have cleared, it did when I reconected the MAF, engine sounding harsh is a bit of an under statement though, sounded more like a Nissan Terrano.......... is it worth cleaning the MAF, what type/size screwdriver undoes the MAF as it has wierd looking screws holding it in.

Thanks

Les

Some say cleaning a Maf helps but i've never found any difference. I would take it for a drive with it disconnected, see if performance is improved which it should be based on the increase in diesel knock and see if the smoke clears. If it does it looks like a new Maf is needed although i'm not certain it ties in with your 2.5-3k problem unless that too disappears on the road test. If you still have an issue at 2.5-3k, 70ish it could be boost control.

Fixings are security torx, some are six point but most Td4s are five point. Bits are available from Maf suppliers or ebay.