Loss of power

[ludok2008]

I have recently acquired a second-hand VW Golf 2001 1.9 TDI. On several occasions now, on long-distance trips, after driving for several hundred Kilometers, there would be a sudden loss of power. Then, even though the fuel pedal is completely depressed, on an uphill I have to change down to third gear and it will hardly reach 80. On a downhill it will still reach about 120 Km per hour. Yesterday, shortly after it happened again, I stopped the engine for about 10 minutes, but when I continued, the same problem was encountered. Then, after about 200 Km, I had to refuel because the tank was almost empty, and when I started again, everything had returned to normal and there was power. At that time I could also hear the whine of the turbo as it kicked in. Previously, when there was no power, I could not hear it, but my hearing is not all that good at high pitch sounds. The problem is intermittent and therefore difficult to demonstrate to a mechanic. I have taken it to the dealers to be fixed and they have replaced the injectors, and yet it still gives this problem. They have also serviced the car recently - without improvement in this regard. I have experimented with different brands of diesel, but that does not appear to affect it. My normal fuel consumption is 5,5 l per 100 Km and yesterday it was 6,4. - It would seem to me that it could be the problem of the turbo, but I can't be sure. 1. Is there a test that I can do myself to narrow down the probable cause? For example, when next it happens again, what should I look out for or try? 2. Could it be something else? If so, what? Perhaps something that impedes air flow or fuel flow? Dirty filters? Any help or suggestions would be appreciated.

[vader]

Hi Ludok2008

If it was an aircooled car you would have been flooded with advice but it's a TDi, watercooled & a Golf... 3 strikes your out.... + you never introduced yourself to the forum members and that could be another reason why no one has replied...

Sorry dude.

I would check the fi pump that there is no blockages and pressure and the fuel filters...
Check the turbo plumbing/dump valve for leaks.
Check the tank as there might be dirt in it which blocks up the fuel pickup when the tank is low... It is for this reason that you should always try to fill up before you hit E for E'FokAllie....

[Chris]

Welcome Indoc2008.

I drive TDi's and have to say have encountered the same problem before.Go to a dealer that can do a diagnostis check.Ask them to check the airflow meter.As it gets older it has the tendency to stop working and then the engine management stops the turbo from working.

When you switch the car off and then on again,it resets and everything works again.

Tell us more about yourself in the welcome thread.

[Tony Z]

If they serviced the car, then it wont be something obvious. Its not the turbo. Its not the injectors as you said.
When you put foot, do you have black smoke all over the place or is it still clear? (get someone to drive behind you).
My first thought was a blocked fuel filter, but you have had the car serviced and its intermittant.

I would guess at a fuel injection system sensor failing (Lambda, air flow or whatever else they have monitoring the air flow).
I would put a bit of cash onto a faulty crank angle sensor.

But seriously, you need to find out what makes this occur and if you can reproduce the problem for someone who knows the cars to check.

[Cyberbeast]

My brother also drove one of those 1.9TDi Golfs for a few years, and the exact same thing happened to him. The car lost power at "random" times, so he took it to VW, since it had the Mastercar plan, and it turned out to be, like Chris also mentioned, the Air Mass meter,or airflow meter, whatever you wanna call it. Basically, it screws up the whole engine management, and the Turbo has almost no effect, leaving you with very little power.

If this is your problem, and you get it fixed properly by VW, you may also notice an increase in power, as the system will then be functioning like it should.

[brianj]

I have an audi tdi.. there are a whole buch of sensors that keep the motor performing. Fuel pressure, exhaust temp, inlet temp, manifold pressure etc etc Now if any of these sensors starts giving trouble the ECU is programmed to either go into SAFE or LIMP mode, or shut down completely. If its the air mass meter for instance, it chooses a mid range value and carries on, although with less power. If the EGT gets too high, it puts you into limp mode till it cools. If the oil pressure drops, the bells go off..
Get it to a dealer, check all the errors on the ECU and find the sensor that is faulty.