91 BMW 325ix wont start

bmw
325

#1

I was driving home the other day and my car stalled. I tried to restart it and all I hear is the starter spinning. I also noticed that the fan and the belt on the front of the engine spins. The engine doesn’t sound like its trying to start though. You know that sound you might get if you were out of gas? It’s not making that sound. It just sounds like the starter spinning. Since the other things on the front of the engine are also moving, I’m guessing that the starter is engaging the flywheel. Is that correct? does anyone know what this could be?


#2

Not clear from your description what this sounds like. Are you saying that the engine is turning over, but it does not sound like it usually sounds when it is turning over? In other words, it is free-wheeling? If so, that would suggest that the timing belt has failed. Can you see the cam if you pull off the oil fill cap? If so, have someone watch the cam while you crank the engine to see if the cam is turning. If the cam is not turning, you have big problems because this is an interference engine - that is, the valves can collide with the pistons. At a minimum, you will need to pull the head and replace at least one valve. Could be much worse. Good luck.


#3

I don’t think that it is the timing belt. I was working on it a little bit today, and I took the distributor cap off. I then tried to turn it over to see if the rotor would move when I did, and it did move. Since the cam shaft drive belt is what turns the rotor, I’m pretty sure, it is working. Also, I know that the plugs are sparking. I investigated that today. A guy up at the parts shop suggested that I check out the fuel pressure and delivery system. I’m going to work on that tomorrow, but if anyone else has any thoughts please let me know! Thanks!!


#4

Maybe all is turning but not timed correctly, do a simple compression test. The compression test is usualy the place to start when the reason for a crank no start is not obvious.


#5

I focused on the fact that you indicated that the car sounded unusual while cranking. If your fuel pump has failed (common problem) or there is a problem in the electrical supply to the fuel pump (another common problem) it would sound perfectly normal when cranking, it simply would not start.

When you turn the key to the On position, you should be able to hear the fuel pump spin up for 1-2 seconds to pressurize the system. If you don’t hear it, you are on the trail of your problem. It may not be very loud. On some cars, I have to put my old ear against the sheet metal of the car to hear the fuel pump spin up.

I don’t recall whether the '91 has a split tank (two small tanks, one on either side of the spare tire) but on split tank BMWs, you can run out of gas when the gauge says 1/4 tank because the fuel is not transferring over to the tank where the fuel pump is. There is a jet pump that transfers fuel between the tanks. It will not work if its rubber seal gets old and shrinks, and it won’t work if the fuel recirculation flow is low because the fuel filter is nearly plugged up.