GOLF TDI ESTATE FLAT SPOT

[coxy1980_123]

Hi ive got a mark 3 golf tdi estate which has a flat spot under acceleration . it seems to die off then boost again . cleaned out the air filter and it seems to be a bit better . but still has the flat spot there a bit . any ideas??? and also theres a tuning chip on ebay its 42 quid and plugs strait into the plug on the diesel pump 8 pin plug and claims smooths  flat spots and increases performance etc whats the verdict on them has anybody tried one out ?? cheers Gareth.

[kahunajb]

I can't help with your issue I am afraid but I would sort it out and make sure it is running as it should before you think about installing an eBay chip.

[Dangerouslyhotdave]

On my Astra 1.7 dti I had flat a flats spot and some random guy I was talking to removed the a pipe on the egr circuit, no flat spots. I thought the guy was full of craap but it was spot on.

Google about it, sometimes works. The engine puts exhaust gas back through the engine to keep emissions down but it kills your power.  Boo to the atmosphere, yay to power and global warming.

[coxy1980_123]

thanks is there any pics of the pipe on the net ?

[Dogbot]

If its also pretty smokey it's more than likely a blocked egr valve, exhaust gas recurculation valve, basically it mixes exhaust fumes with fresh air in the intake to optimise fuel economy, emissions an the likes, they usually get blocked an need cleaning or replacing, I personally have always removed them an blanked them off as that's what we always did with the land rovers, vauxhall also did this on a recall to some of their diesel engines, lots of arguments for an against taking them off  but I would suggest at the very least cleaning it through

[Diamond Hell]

Could be EGR, but also unplug the MAF and see what it drives like when that's disconnected.  It's the electrical connector on the inlet pipework, left hand side of the bay.

[coxy1980_123]

thanks guys its not smokey at all its just that flat spot . apart from that car runs really well . 

[coxy1980_123]

also forgot to say that the car when on the motorway travelling at a steady speed it will die back and boast again .

[coxy1980_123]

bump

[Rmachines]

Sounds like it could be the EGR Circuit,  this will activate under cruising and light boost conditions usually.

I cant remember if the EGR Has a needle lift sensor off hand,  if you take a look at it,  You can disconnect and block that little vac hose (remember to block it though)   And see how it goes.

If it has a two pin connector to the top of the EGR, that is the needle life sensor, and it will log a fault code if you disconnect the vac hose,  By all means try it,  however this may put it into limp mode in which case you will have a very big  flat spot, If that happens, reconnect the hose, and switch engine off and on again.

If it still happens with the EGR disconnected,  Remove the EGR Valve, and see if the poppet valve is stuck open, if it is, clean it up as good as you can so its closed, then refit,  you may want to leave it disconnected as it will stick again, or of-course if you diagnose it as the EGR,  Replace.