Car won't start

[shogun]

It does not matter if you can hear the fuel pump or not. You have to test it, that is the only way to be sure if it works and if it pumps the required volume.
On my 750 I have 2 fuel pumps, some month ago car was running only on 6 cyliners. Then I tested the fuel pumps by giving direct power to the fuel pump fuses in the fuse box (bridging the fuse). Both pumps where whirring. Then I tested the fuel lines in the engine room, one was full of pressure, the other one was very weak = one pump was still whirring but actually did not have enough power to pump.
If you have more sophisticated test equipment, attach a fuel pressure gauge in between the fuel line and see how it is working. But a test by finger onto the fuel line tells you also a lot.

Another point; check all wirings again were you worked on amps, speaker etc.
If the car ran before you worked on the car and then does not run, check always first the area where you worked last. Maybe a wire not connected.

[DDK's 525]

car is a 90 525i. I replaced the entire stereo today, new amps, head, speakers, and wires. I did all the work with the battery disconnected. Now the car turns, but wont fire. for the last month or so, on occasion it would start hard, needing to crank longer and give it some throttle to start. Also some mornings it will start and die right away, but starts up again with some throttle. Now nothing.

Fuel pump seems the obvious thing, but is there anything else to consider? The windows and sunroof work fine, so I don't think it would be the fusible link. Could I be wrong? I had my wife turn it over and listened to the fuel pump, I did not hear anything while it was cranking, but when she stopped it made a weird kinda growl.

Thanks for any incite you all may give.

[DDK's 525]

I will check for pressure tonight. I only have my finger to test with, if I can stop the flow, or slow it down, I guess I know the answer. The only factory wires I messed with was the - on the battery, and the hot, accessory and antena leads from the factory radio. Everything else was run fresh, new 4ga power from the battery to the trunk, 3 sets of RCA from the head to the trunk, a remote turn on from the head to the trunk, and all new speaker wire. I don't see how this could have messed up anything. I did have the rear seat out, is there anything there in a '90 that could mess things up? I'm not afraid to replace the pump, I just don't want to throw money at the wrong solution.

Thanks again.

[shogun]

There are also relais, modules and fuses under the rear seat driver side, select the proper wiring diagrams for your production year, from about page 15 there are drawings what is where, and a list of all fuses and for what they are.
http://shark.armchair.mb.ca/~dave/BMW/e34/

[DDK's 525]

If the pump is making sounds, would the relay be bad?

[whiskychaser]

If the pump is making sounds, would the relay be bad?
Probably not. Best thing you can do is jumper the relay to get the pump to run without you cranking. Then check the pressure. IIRC its 50 psi. It will drop to about 45 due to inlet vacuum difference with the engine running. Best get it checked properly as a 'finger on the end' test probably isnt accurate to a few psi. Murphy's law states that if the pump decides to give up it wont be as you turn into the drive - it will be miles from nowhere.

[DDK's 525]

Ok, I pulled a spark plug to see if I get any spark. Grounded it to the Valve cover and the mount that holds the intake runners and got no spark. I also smelled gas which I assume is from the open hole. So now what? Crank shaft sensor? when I put the - back on the 1st time, I did get a spark bridge across, could this have hurt anything?

[whiskychaser]

Ok, I pulled a spark plug to see if I get any spark. Grounded it to the Valve cover and the mount that holds the intake runners and got no spark. I also smelled gas which I assume is from the open hole. So now what? Crank shaft sensor? when I put the - back on the 1st time, I did get a spark bridge across, could this have hurt anything?
Valve cover isnt a ground, If you cant get to somewhere that is, use a jump lead from plug to ground. Very very unlikely you caused any damage

[pingu]

I'm not sure that the valve cover isn't ground (I guess we're talking about the metal thing, not the plastic vanity cover!) - it's bolted against the engine?

But agreed that the natural inclination of a fuel pump is to fail miles away from anywhere!

[DDK's 525]

Ok, tested again to multiple points, still no spark (and smell gas comming out of the sparkplug hole). Checked the coil and it tested good. on the the crank shaft sensor, but how do you get the plug off the harness?????? I traced it back to a long harness unfer the intake. The plug face down so there is no way to see it. I looked from underneath and can see, but I can not get it off to even test. I feel a spring type clip that locks it on which I can release but it does not want to pull down and off. Which way does it go? or am I in the wrong spot?