Dear All,

We bought the defender but shortly afterwards it started to show much reduced power on the motorway maxing at 60mph and not getting above 3000rpm. The engine light showed some fault codes about air intake and underboost.

There had been a problem with fuel contamination involving the fuel tank having to be cleared out and sediment in the fuel cooler by the prev. owner.

I took it to Paul at Foleys. He replaced 4 injectors, and said the fuel pressure was ok, and replaced the fuel filter.

The problem recurred after some time on the motorway. Randomly I discovered that the low power was fixed generally by a restart of the engine, whereupon it could get back up to 75 in sixth no problem, but then the power would randomly drop off again at high speeds. And the engine light came back on again.

Does anyone know what might be happening from these strange symptoms? What should we look at?

Many thanks,
Chrisantha

Chrisantha said:

Dear All,

We bought the defender but shortly afterwards it started to show much reduced power on the motorway maxing at 60mph and not getting above 3000rpm. The engine light showed some fault codes about air intake and underboost.

There had been a problem with fuel contamination involving the fuel tank having to be cleared out and sediment in the fuel cooler by the prev. owner.

I took it to Paul at Foleys. He replaced 4 injectors, and said the fuel pressure was ok, and replaced the fuel filter.

The problem recurred after some time on the motorway. Randomly I discovered that the low power was fixed generally by a restart of the engine, whereupon it could get back up to 75 in sixth no problem, but then the power would randomly drop off again at high speeds. And the engine light came back on again.

Does anyone know what might be happening from these strange symptoms? What should we look at?

Many thanks,
Chrisantha

Click to expand...

ive had a few similar which turned out to be turbo actuator, its an motor that alter variable vanes in the turbo to control the amount of boost either the actuator or the vanes fail, if you look at actuator rod while someone revs engine you should see rod move

Thanks James,

So if the actuator does not move does it require replacement of the whole turbocharger unit? Should it move when stationary and in neutral? Why does it solve itself after a restart? I saw this posted elsewhere... Don't know if a similar thing applies to the TDCi. Thanks again for your help.

"I had the same problem on my TD5 Defender - turbo wastegate actuator stuck closed.

What happens is that when you apply power, the boost goes up but continues going up because the wastegate isn't opening to regulate the pressure properly.

The Manifold Absolute Pressure (MAP) sensor senses this excess boost and protectively switches the ECU into "limp-home" mode with limited fuel-delivery.

Switching off and restarting means the 'limp-home' is reset to normal - until the next time the boost exceeds the programmed safety-threshold."

depends if its the actuator motor fault or vane moving issue in the turbo or both, these turbos dont have a waste gate as boost is controlled by the vanes, you should see some movement even when revved with no load, but if its intermittent problem it can be more difficult to find or in your case showing at higher load conditions

thanks so much, thats very kind. C

Random maybe, but when I had an Audi 1.9 TDI, the vanes were notorious for sticking on those, and is DIY fixable;

Get some Mr Muscle over cleaner (I kid you not), got to be the foam type one, fill the turbo housing with it, leave it for a good half an hour, and then run the engine.
On the Audi, you could literally pull the EGR hose off, and fill the thing to the brim with foam.

Just making sure I'm clear, you only fill the exhaust housing, not the intake housing.

It frees up all the soot and stuff from the vanes, and gets them free moving.