CASE STUDY N42 NON-START
We recently had a 2002 318Ci that wouldn’t start. It would almost fire up, but it couldn’t quite manage it. The car had been standing for some months following a non-start and the garage couldn’t seem to fix it. A new crank sensor had been fitted, which at least got the car to attempt starting, but didn’t resolve the situation. Without a diagnostic reader to at least drag up some fault codes, this was going to be a struggle.
A good battery is a start, so the engine can spin over good and fast – if the battery is only average, it’ll never start. The cam cover was removed to check the camshaft timing with the locking toolkit, and although the chain and guides were original and due for replacement, the timing was near enough and certainly good enough to start.
Next, the plugs were replaced, but still no joy. Given that there was fuel at the injectors (you could smell it from the exhaust) and there was a miserable spark, attention was turned to the crank sensor.
BMW handily buried this at the back of the block in such a way that the inlet manifold needs to come off. Not too difficult, albeit not very pleasant. A known good working sensor was fitted, the car reassembled and tried again. This time it really was trying to start, but just seemed to get bogged down.
We pulled out the fuel pump fuse and cleared its throat a bit. For this, we held the throttle body plate open with a screwdriver handle to get some clean air and dry out the plugs and bores. A good five-second shot of Bradex Easy Start down the intake got it to run for a few seconds. Then, with the fuel pump fuse refitted, it coughed into life and ran, albeit not very well. So the engine was switched off, restarted and the previously glowing EML light went out and it sounded much better.
The causes?
A Lucas crank sensor that just didn’t work properly (only ever use a genuine BMW part), worn plugs and flooding. We later found out that an incorrect exhaust cam sensor was fitted, so with a pair of good used ones fitted and the fault codes cleared (plus Valvetronic adaptions reset) it was running much, much better.