Thread: Severe power loss - help needed!

Originally Posted by Cloughy

There is also quite a lot of black smoke on "attempted" acceleration.

Based on that I'd like to take my money off the fuel pump, and put it on delaminated turbo hose(s).

Suggest it is definately not the hoses as they have just been replaced with silicon hoses - to be honest I suspected delaminated hoses too, which is why I replaced them. Just thought of another issue too, the fuel consumption has risen dramatically since the problem started.
Cloughy

Isn't the FPR leaking?

Looking at your capture it looks like you are massively underboosted, maximum boost was 5psi and air flow was corresponding.
You also registered a slight negative pressure, which I can't see on my two quick captures from my own I have available. But my engine capture (not instrument) registers as high as 216kpa at map with ~100kpa at inlet, which is 16psi (ball park max pressure for a stall test, but the turbo has just been replaced and the new turbo showed 19psi on an actual run).
Wastegate is modulating though (which I suspect is nanocom not telling the full story about whether the modulation is to close or open).

I wonder if the negative pressure and low boost indicates you have a leak somewhere?

A leak between the turbo and inlet would keep the boost low but let the MAF rise as the suction should be good then cos the turbo makes it's job just that the boost is lost somewhere.... in this case the MAF being low too so IMO it's a sign of intake/inlet/exhaust restriction(which seems to be ruled out) or underfuelling which can be HP stage of pump failure, fuel leak, FPR failure or the strainer under the FPR clogged(quite rare but happens)

Originally Posted by sharmy

Sounds like it is overboosting, You can check by bypassing the wastegate module by running a tube direct from the aftercooler pipe to the waste gate accuator. It can be caused by split rubber hoses or a faulty module, they are not expensive to replace.Presuming it is a td5
John

If this was the case it would likely surge form my experience.

Is this a late model TD5? 2003 or later? D2a? The reason I ask is they have an extra sensor in the air box, ambient pressure sensor and the ECU uses this to compare the MAP to check boost levels. Perhaps this is giving a false (probably high) reading if you are confident the hoses are OK.

Silicon hoses are also difficult to tighten, there are many threads about new hoses coming loose. Many people rough up the inside ends with emery paper to provide more grip for the clamp.

The exhaust smoke indicates over fueling or not enough air. This supports the conclusions so far about restricted air flow. Perhaps remove the air box lid and go for a SHORT drive.

Originally Posted by Jazzman

Is this a late model TD5? 2003 or later? D2a? The reason I ask is they have an extra sensor in the air box, ambient pressure sensor and the ECU uses this to compare the MAP to check boost levels. ...

Not to contradict just for accuracy, they all have the ambient pressure sensor, the 15P modells have additionally an ambient temp reading from the same sensor(4 pin sensor instead of the 3 pin sensor on 10Ps) but this signal is used for EGR overtemp protection, as about the AAP reading i have nothing to add