BMW Repair: 1995 325i: Rough Start -> Now No Start, camshaft position sensor, fuel pump relay switch

Question
My 1995 325i began starting rough about 3 weeks ago (would crank for about 3-5 seconds and then turn over), now the car will not turn over, but still cranks at a normal speed (i.e. not battery, not belts).  I've tried to listen for the fuel pump turning on, but I don't know what I'm listening for.  I've checked the fuel pump relay switch, as well as power to the fuel pump - all of which show voltage and resistance.  I've replaced the spark plugs, but don't know how to check for spark?

Loaded question I know, but your help would be greatly appreciate before I buy a 200$ fuel pump that I may not need.

Answer
Hi there.

You need to check that you have the following...spark, fuel . Check for spark by removing one of the plug wires including the respective coil, and inserting a screwdriver in the end touching the terminal, then get a mate to crank the motor while you hold the screwdriver close to the nearest metal part of the car to see if you get a spark (it should throw a spark to the point where you earth it near to, but not actually touching the body/motor). But, I doubt that's your problem. Check for fuel pressure by removing the fuel line where it connects to the inlet manifold and cranking the motor or just switching the key to the ON position. No fuel and there's your problem.

You can remove the fuel pump to check it by gaining access under the seat (its the one under the right hand seat with the two electrical connectors and two fuel lines) and connecting this to a voltage directly (obviously not near the now open tank). You can also bridge the pump relay terminals 2 and 6 to see if the pump motor runs continuously. Pump failure is fairly common on these as there is a small weld where the connectors join under the pump lid. These cannot be soldered as they will break after a few days.

If you have fuel but no spark, you need to check the Crank Position sensor for resistance as well as the Camshaft Position sensor. this could lead to similar problems.

Check for fuel and spark, and get back to me if you need to, as we might have to try a process of elimination.

Regards

Rob