3.0TDi hunting at low speeds

[tgm147]

Hi guys

One day I'll put a post on this forum without asking for help!

The car is a 3.0TDI on a 05 plate with 48k miles on. Driving on the motorway it's fine, hard acceleration appears to be fine, but just cruising along at 30 the box feels like it's hunting between 3rd and 4th. Does this sound like an issue with the box or just a characteristic of the box? It's quite annoying that it won't just cruise along without the engine note constantly going up and down!

Cheers

[ScottD3]

Mine is a 06 plate with 170k.
Does exactly the same thing.

I've had the box serviced and full service history for the engine.

No idea what it is.
I'm siding with the box.

[tgm147]

Mine is a 06 plate with 170k.
Does exactly the same thing.

I've had the box serviced and full service history for the engine.

No idea what it is.
I'm siding with the box.

Sounds good. Going to try mapping it, see if the extra poke low down will stop it hunting if other peoples boxes are the same. Will let you know!

[ScottD3]

I dont think its normal.

A fix would be good.
It ****es me off

[Burnzybubbles]

Unfortunately it's not normal, guessing nothing is showing up on VCDS?

I would of suggested a service but if Scott hasn't had much luck them maybe it's a sensor in the box that's playing up, is it getting the correct speed signal? Maybe try logging some data from the box see if anything unusual crops up.

[ScottD3]

No errors for me.

Not sure what to log from the box but a good idea.

[tgm147]

Still waiting for VCDS to arrive but I do have access to Delphi Diagnostics which are pretty good. I'll have a play with it tomorrow, see what I can dig out.

[tc4332]

Just for interest.
Mine is a 2004 3.0 D3 TDI.
I had it remapped, then a while later the ECU died with me stuck at the roadside. Replaced the ECU with a used one from Germany, my Indie fitted and then remapped it for free. Very good result. Now some eight? months later and still good.
I have never had transmission hunting at any speed (lots of 30mph) with either of the ECUs, before or after mapping.
OK mapping gave me much more oomph and better fuel consumption. Well worth doing.
My Indie tells me that the ECU is a common one used in plenty other marques in particular Range Rovers, just a different map, so should be cheapish to replace. As long as you know what map to programme in :cool:

[tgm147]

Just for interest.
Mine is a 2004 3.0 D3 TDI.
I had it remapped, then a while later the ECU died with me stuck at the roadside. Replaced the ECU with a used one from Germany, my Indie fitted and then remapped it for free. Very good result. Now some eight? months later and still good.
I have never had transmission hunting at any speed (lots of 30mph) with either of the ECUs, before or after mapping.
OK mapping gave me much more oomph and better fuel consumption. Well worth doing.
My Indie tells me that the ECU is a common one used in plenty other marques in particular Range Rovers, just a different map, so should be cheapish to replace. As long as you know what map to programme in :cool:

Your indie is correct, it's a common ECU and the Bosch EDC16 series are very hard to kill when remapping (unless they've not been sealed properly after they've been opened and you get water inside them). Not like the Delphi ones that appear to pack up for a laugh when writing maps to them! I do remapping for a living but I'll say no more, don't want a telling off for advertising or anything! +++

I'll put Delphi on it today and see if anything looks out of the ordinary. I wonder if it's a software update issue and cars that have either had the box software updated or left the factory with it aren't effected?

[Dezzy]

Your indie is correct, it's a common ECU and the Bosch EDC16 series are very hard to kill when remapping (unless they've not been sealed properly after they've been opened and you get water inside them). Not like the Delphi ones that appear to pack up for a laugh when writing maps to them! I do remapping for a living but I'll say no more, don't want a telling off for advertising or anything! +++

You should be alright as long as you're not stepping of the toes of the sponsors, I don't think there will be any telling offs for advertising a service massively discounted to forum members :D If you were to advertise "Breaking A8 all parts available" it might get pulled.

[tc4332]

My Indie does remapping and has done quite a few A8s including my mates that is used as a business vehicle, mine is just a personal family use car.
On most he is able to do the remapping by plugging into the OBD/VCDS connector, but on mine and one other this failed to work and in both cases it was ECU out, opened up and set up on a bench rig. This happened with the replacement ECU as well. No explanation for the problem.
He gained a lot more expertise doing mine and was rather happy at the learning curve. I can't complain because as well as doing the second one free of charge he also refused payment for doing the first one. Result :ROFL:

[tgm147]

Just as a little update on this, we stuck a map on it a few days ago and (all other random electrical issues aside) the map has stopped the box hunting! Car feels much more eager to go now too. I need to try and find a local 4WD rolling road but at a guess it should be somewhere between 280-290bhp now. And only a little puff of smoke too on initial kickdown which is good. Not the kind of car that suits clouds of smoke coming out the back!

He's gone away in it for a week now so will get a proper report on economy. On the run to Santa Pod we did it it, it averaged about 38mpg. If the map pushes this north of 40 I'll be pleased.

Nice and easy, done through the diagnostic port. Definitely needed the battery stabiliser on it though. Should use one anyway no matter what but really wouldn't try and read on one of these without one. 15 minutes to read the ECU via the diagnostic port.

http://i60.tinypic.com/2q8q6ab.jpg

http://i57.tinypic.com/ifd5x0.jpg

[ScottD3]

Gearbox of engine map?

Good news on it solving the hunting.

[tgm147]

Gearbox of engine map?

Good news on it solving the hunting.

Engine map dude. It looks like modifying the torque limits in the engine map have allowed it to hold the gear properly.

He's still on holiday in it until the weekend so will report back properly then if it's fixed it.

[ScottD3]

Thanks good news.

Hopefully it will solve it permanently.

I'll look in to maps.

[tgm147]

Epic thread bump.

The gearbox still appears to be fine. Under very, very light acceleration it does still try and hunt between gears but accelerating normally it changes smoothly and does not hunt when sat at 30mph.