chipped passat 115pd behaving badly

[timmythedog]

Having had my 1999 1.8T estate remapped by REVO to great effect I have now moved on, a) because it was too juicy b) I prefer to run a diesel.

So I have bought a 2000 w reg Passat 1.9TDi 115PD Sport estate, which it seems is quite a rare old car.

Anyway it drove impeccably and seems to have been well cared for, but after the mapped 1.8T was obviously a bit sluggish. I decided to buy a tuning box for £300 from Powerklick. Fitted it up and drove around for a couple of days. Had to remove it because it developed some horrible little niggles.
The worst of these and probably key to them all is that when on a motorway at a constant speed, could be 60mph, or 90mph it felt like a petrol car with a coil or lead breaking down. Or, like you were towing another vehicle who was applying and releasing the brakes constantly.
Other small clues were, the turbo boost seemed to switch on and off in a rather primitive way.
Consequently I removed the box and returned it, deeming it faulty. We switched for a different brand, a Vector, and tried that. Same result. The car returns to normal when removing the box. So assuming the boxes were okay, which seems likely as two in a row faulty in unlikely, they seem to highlight a problem on the vehicle that is not detectable when standard.
Iam thinking, what would cause this behaviour in a standard car. Shall i try and eradicate it by taking the same steps.
MAF?, or N75 boost control valve seem to be what the forums are saying. Or is it more complex?
Any offers gratefully appreciated on this or I may bin the boxes and go for a remap.
Cheers for now, Timmy The Dog

[6Speeder]

I'd have the car checked for fault codes if i were you. If it all checks out then get a remap done...they are a far superior (more balanced) way of doing things than the overfueling frig boxes.
Just my opinion of course

6

[glynnd]

I agree totally about tuning boxes. The only one I know works properly is a unit which modifys the injector signal(mr hoot .com). I tried an analogue tuning box on Passat tdi 130, the idle was awful, I got my money back. A remap is the only way to get a proper performance increase.

[timmythedog]

Okay, so i could be dealing with a bad product? I don't think this is an analogue tuning box. It's not one of those £30 plug ins from ebay, it cost £300 and is from a reputable german company, so I believe! The first one i tried was a Powerklick. They do have a very persuasive web site, but I guess that's easy to achieve.

Having tried two in a row I am still inclined to think there could be a fault with my car, although it would not seem that way as everything returns to normal when the box is removed.
I fitted a new MAF yesterday. It is a genuine Bosch exchange unit. It definitely improved things, but the fault is essentially still there. On a warm start up it revved itself up to about 3000 and I had to switch off.
The power delivery is still erratic with turbo boost coming in spurts and then shutting off as quickly as it started. Not what I was looking for.

The box aside can anyone identify with these symptoms, which maybe, just maybe, are being exxagerated or brought to the surface by the presence of the box??? I wish I could afford the car I want, then i wouldn't have to meddle in this game! Cheers for now.

[6Speeder]

Like i said get fault diag. reader plugged into it. Any good reputable vw specialist will have one, or maybe someone on here with VAG COM will be able to help out if they stay near you.
I'd get to the bottom of this before i'd contemplate any more tuning, you never mentioned the mileage. It could be sticky turbo vanes, also take the bottom hose off the intercooler to check its not full of oil.

Good Luck

6

[timmythedog]

Cheers 6 speeder. Will have a look at that hose now. Car has done 100k. Very good history to date. Just had a chat with someone who knows this box and said it does not give a smooth upgrade to the 115pd! Reckons it's fine for hard driving but will feel lumpy if you are light on the throttle, which I am, so that may be a big part of what's going on. It's all starting to make sense! Anyway thank's for advice to date, and will keep tinkering.

[glynnd]

I have had a few intermittent probs with my passat. One day it flies the next day it feels a little flat. Had the mass meter checked and it was fine.
I clear the oil from my intercooler every now and again. I have been told the wastegates on these pd engines can stick(my car has done 95k) also as 6 speeder says the vanes can stick too. Make sure you help matters by using good quality fuel and if you are on pd oil change it every 5000 miles. After adhering to these points my car now flies all the time. last week I alsop added some friction reducer to the oil which again has made a difference too.

[timmythedog]

Thanks Glynnd

I have just been crawling around under the car, removing wheel arch shield and lower sump tray. Took off lower intercooler hose and a small amount of oil dripped out so I cleaned I mopped that up. Do you clean the whole system out and if so how? Is that hose the likeliest area for a build up?
Have now removed the tuning box after tinkering with the 'jumper' bar that allows you to further boost or decrease power. Went for a big blast and it was almost leapfrogging, although going like a train as well.
So I have removed the unit and my car is once again behaving faultlessly.
A waste of time, and money. Have been promised my money back so will take that and think about a proper re map instead, though it's quite nice having a civilised car again. By the way, which model is yours?
Cheers, Tim.

[glynnd]

Have a 130 se, I clean the cooler thru with my jet wash and also clean the pipe from the top of the cooler to the plastic boost carrier. Helps if you prevent the build up of oil in the bottom of the cooler!