engine surging under full throttle

[97diesel]

I,d say this question has been asked before but i hope someone can help here,the wife and i are upgrading from out '97 tdi auto to a '03-'04 td5 auto, we took one for a drive this morning low km's (79000) and i noticed that under full throttle up hill the engine started to hunt and surge, which i thought was a bit unusual. under light throttle no problem only when throttle is on the floor under full boost. We have driven a couple now and the others have not surged like this,the vehicle is spotless inside and has service history but the surging has sort of put me off from taking it any further with the dealer.
We have decided to keep out D1 and give it to our son who will have his licence soon and just purchase the D2 without a trade (mrs can bear to part with her D1) but really wants a D2. any advice would be greatly helpful.

[Barney2803]

It has been on here before, lots of posts I reckon but.... Mine was doing similar recently (04 TD5 disco) and I put injector cleaner in over a few tanks and it was all ok for months and it's started doing it again. I'll do more injector cleaner now and see... Otherwise the gurus on here will mention over-boost and stuff like that.

You won't regret going from a mid 90's to a D2a... I did the same and love it!

Sent from my iPhone using Forum Runner

[scarry]

Often the MAF does it.Easy fix,needs replacing.Some guys clean it,mabe OK,but better to replace it.

[davrac]

Hi, I agree, you wont regret the upgrade as long as you are willing to carry out the minimum fixes -

oil pump bolt
engine saver, coolant level sensor
Injector o-rings and wiring harness

The cut out under full throttle will probably be because someone has increased the boost. the cut out is about 19-21psi. In relation to the MAF (air flow meter) they gum up quite a bit and can usually be cleaned with a good quality contact cleaner without the cost of replacement.

Pros and cons to the td5 upgrade. if you have a good tdi and are not mechanicaly minded stick to the tdi. The td5 can be a little maintenance heavy i'm afraid whilst still a good strong engine if maintained.

The rest of the DIIa is a very nice upgrade from the 200-300tdi models.

Good luck

Dave:D

[northiam]

Turbo over boosting! mine was doing the same as you discribe.

[97diesel]

Thanks for the advice fella's. As we havent purchased the vehicle im not overly concerned, salesman was a bit pushy about putting a deposit on it today, but the surging has made me hesitate for the time being, there were another couple of things that i noticed that were a bit strange for a vehicle with only 79000km's on the clock (front disc's badly worn, rear springs replace but not the front)so it was sitting as though it was going down hill.We have driven a few others but one stands out over the others,so we will see what happens next week.

[Pedro_The_Swift]

nothing unusual about worn discs at that distance,, the discs are cheap to replace,, the harder question is buying pads that dont squeal;)

I can pick 5 seater D2's a mile off by their bum up attitude:p


TD5's at that kilomeratige are not common----:cool:

[scarry]

As said,discs worn out not uncommon at that K's.

I alsways fit genuine pads,no squealing.

Rears were probably changed as the OEM's are a bit soft for loaded touring,the fronts have probably sagged,particularly if it has a front bar.Check distance between bump stop & axle at front.

My coiler sits almost level with a full tank of fuel after i fitted kings standard coils to the front.Originals had sagged.

the D2 a is the best of the D2's by far,make sure the car you are looking at has a full service record.

[Wasa57]

My td5 was surging as you describe, turned out to be a faulty valve that regulates turbo boost. Someone more knowlegable may wish to elaborate.
It was a simple and cheap fix.