[mlmcelligott]

My 320d e46 has always been a bit sluggish up until about 2000 RPM and then it gets fairly lively. Tonight I took some screenshots with INPA and got some very high MAF readings and some engine errors but I dont know what all this information means...

the bottom two screenshots are the ones in question with high MAF readings. the first one is a idle speed and the 2nd at 2000RPM

the engine error code was
4501 Exhaust Gas Recirculation- Negative Deviation or Air Mass too High

 

[TorqueWorks]

for a start, your engine is cold.. so the car wont be right until it warms up fully


if the readings are in the green band, its acceptable values... you could try disconnecting the MAF to see does it run better on a factory map

 

[DavidK]

Check the hose on the egr, or pull the egr off and check to see its not totally clogged.

You should also consider pulling off the intake and giving it a bit of a clean.

 

[mlmcelligott]

I took out the MAP sensor this morning and it was clogged up with gunk so i cleaned that out with carb cleaner and put it back in. After 15 minutes of idle running I took the below readings again. It now appears to be over boosting since the MAP sensor can now measure the air intake manifold pressure more accurately. I had the EGR and air intake off only 3 months ago and cleaned them thoroughly and replaced all gaskets so im confident they are clean enough unless the EGR has gotten stuck closed now.

 

[ciars]

unless the EGR has gotten stuck closed now.

Worth a look, given how accessible it is. What did you use to clean it? How smooth was the piston movement pre and post cleaning? I ended up replacing mine for a brand new one when it was giving bother (sticking).

 

[healyc]

Run it for longer as the car is only at 55celcius, get her hot hot hot

 

[ciars]

Run it for longer as the car is only at 55celcius, get her hot hot hot

Speaking of which, what would you say is typical of optimum temps Conor? 92ish degrees?

 

[mlmcelligott]

Just back from a test drive and the car has improved considerably.

Before I left i took out both pressure converters that serve the turbo and the egr valve. Theres a little filter on each one that had a very thin layer of black dust that must have gathered over the years of driving and had them fully blocked. I cleaned them out with carb cleaner and then swapped them as the turbo one usually gets worn more than the egr one (they are both the same part number).

The car pulls much better now with even boost all the way up through the rev band. Ive never known the car to drive this well so the pressure converter filters must have been clogged up well before i bought it three years ago!