Audi A4 1.9 TDI BRB Engine - Throughty Sounding Engine - Intro
A few months back my ECU logged a P0299 fault code on our audi 1.9 TDI PD (BRB). On opening up the engine I notice a split pipe that returns exhaust gas from the EGR cooler, which its self was loose.
Not being a mechanic, a tightned up the EGR cooler mounting and welded the pipe back together.
What I should have done was considered why the EGR cooler had come loose.
Audi A4 1.9 TDI BRB Engine - Throughty Sounding Engine - Cylinder Mis-Fire
To my untrained ear the BRB engine had always sounded bit "butch" and noisier than our other 1.9 PD powered VW. The noise it turned out was actually a mis-fire of one cylinder.
The problem was that the previous owber had driven the car 120,000 miles for some or all of which he had used a low grade oil. This had resulted in the can shaft lodes wearing down to the point wehere, the exhust valve from one of cylinders no longer opened, which meant the only route was back out through the inlet valve.
This results in a lack of power, and a severse accelalration lag, ending in a jerky accelaration.
On inspection the lobes on the cam shaft were noticlbly worn, and you could see the wear with the naked eye.
It is likley that this forcing of exhaust gas back through the inlet valve caused the over opressurusation of teh EGR system, which may have caused shrink swell and subsequent lossening, and eventually the split EGR return pipe.
Audi A4 1.9 TDI BRB Engine - Throughty Sounding Engine - Advice
If you looking at buying a BRB powered Audi with a throughty sounding engine be very cautious.
Repair bill for above £1700.