Weird starting issue
 

I recently acquired a 95 320i and it's starting very oddly. The car will only start if I put the key to the ON position first, wait 5-10 seconds then try to crank it. It starts everytime this way. If I try to put the key in and go to an immediate start, the engine will crank but won't start.

Any ideas?

My friend had this problem on his Mustang 5.0

I hypothesized that the fuel system was not holding pressure at shutdown and it took a second for the fuel pump to build up the proper pressure.

Another guess would be that an electronic component is "rebooting" every time you switch to on.

I think it does have something to do with fuel pressure. What would be the cause of that and will it cause problems later on? Thanks for your help.

He has driven his for years with this problem. My guess is it is the pressure regulator but I wouldnt just go out and replace it without some research. The problem is probably generic enough that you could find info on the web easily.

clogged fuel filter??

Not sure if this applies to 320 or not, but many cars have a non return valve in the pressure line at the fuel pump. These often break and I have heard of people doing makeshift repairs and eliminating the valve. You may want to check the feed line at the fuel pump if it's not too hard to get to. Other than that if it was my car I'd just drive it as is and not worry too much unless things get worse

It sounds like your fuel pressure is bleeding off and the pump is having to repressurize the system everytime. Does it happen if you turn it off then try and restart it immediatly? When you are driving does it act slugish in any way? It could be the pressure regulator, the relay sticking alittle, or your pump itself might be letting pressure bleed out. It just takes a little bit at a time to eventually depressurize and as long as it doesn't bleed pressure too quickly it wouldn't effect driveability too much or at all.