Posted by S54B32 - M3 E46 Engine Second Life: Diagnosis
The First 300 000 km
A wise man once said that nothing lasts forever. If we look through the eyes of a “cardiologist” at the heart of an E46 M3, which is running fast to the 300-thousand kilometer mark on the dash it is very likely that more and more we are asking ourselves how much it’s going to last and what really is going on in there, deep between the iron walls. And also is there something that can be done in order we avoid having a heart attack? I use “we” because should a malfunction of such magnitude happens to the subject “heart” then the risk for the real heart of the E46 M3 fanatic owner is quiet serious. Or at least his bank account is very likely to suffer a major recession.
The main character of our story is an S54B32 engine, powering an individual Sterling grey M3 which has seen two owners in her parent Germany before being driven to Bulgaria exactly nine years ago. For the seven years on the German roads the subject motor has accumulated slightly above 150 thousand kilometers. Every year its “blood”, Castrol 10W60, has been changed and apparently it hasn’t been abused judging by the condition of the body it powers. In Bulgaria our S54 is enjoying extensive care – every fall and spring along the tires of the car it has the oil changed or at 10 thousand kilometers mileage max. At 200 thousand kilometers the rod bearings were replaced preventively due to unknown status of previous change and infamous known cases of spun bearings and damaged beyond repair crank shafts. Every four years the valves are being adjusted, the spark plugs replaced, belts and pulleys at around 80 thousand kilometers.
Tuning and Mods Unexpected Results
It was somehow natural the way that some mods found their way to the inlet and the outlet of the engine: namely a K&N cold air intake and Supersprint exhaust system except for the headers where the OEM remain untouched. After the Supersprint high flow cats were installed at every few hundred kilometers the “Check Engine” light kept coming on the dash. This was due to the rear O2 sensors did not really “like” the exhaust emissions quality. In order to get rid of this annoying little fellow and to optimize the engine performance a little bit it was decided that the ECU will pass through a custom remap.
The first run on the dyno – shocking 215 wheel hp! Except for the mods just an year prior that moment the VANOS system went through a complete overhaul with repair kit made by the US based Beisan Systems, the best proven solution for the S54 VANOS. And it was working flawlessly. On the very same dyno stand a stock car in known good health usually hits 260-265 wheel hp. After the first remap – almost no change. After few try outs with disastrous results a run with unplugged mass air-flow (MAF) sensor was done and there you go – 20 wheel hp more with very smooth curve. It was already clear by that time – despite that there was no fault code generated, the MAF sensor was gone and the fuel-air ratio was completely off.
Much more “interesting findings” are still to come…
So stay tuned for Part 2!
