This is my first post here but I’ve been searching for an answer to this problem for at least 1 week, 2 hours/day all over the internet. Other people have had the problem but there are no answers . . . are you ready?

We just bought a 1994 525i with 191,000, in great shape, meticulously maintained by an engineer. My wife drives 15 minutes to church and it sits for about 15 minutes. She then tries to start it again and it turns over (sounds like good compression) but it doesn’t fire up. A quick diagnosis: no fuel pump noise, bad fuel pump. I buy a used fuel pump off eBay while I’m waiting for my dad to loan me his volt meter. The volt meter says no power is going to the pump (fuse 23). Because I don’t know which relay is for the fuel pump I checked every relay under the hood and only 2 refuse to snap: one large relay with about 8 pins in the driver side fuse box (across from the crash alarm relay, separated by the LKM I think), and a five pin relay by the ECU – yes, the DME or the main relay. I buy a new DME and still no power to the fuel pump. I finally find the fuel pump relay by testing for resistance to the hot side of fuel pump fuse, and replace that relay (even though it was snapping). Still nothing.

Jumped the fuel pump relay with fuse 23 in its proper place and guess what I hear . . . the fuel pump in the trunk and the injectors (I think) in the engine compartment) which makes sense according to the wiring diagrams (the fuel pump relay runs both). All the contacts in the relay plug are working fine: 30 is hot all the time, 87 grounds out after going through fuse 23, the fuel pump, and the injectors. When the key is turned, 86 is hot and is sending 12 volts through contact 85 which grounds out without a problem. Still, with the relay in place no power goes to the fuse.

When I turn the engine to try to start the car *and* jump the relay, the pump runs fine but the engine still won’t start. I don’t smell a lot of gas coming out of the exhaust but I’m afraid I will flood the engine if I keep running the pump/injectors w/o the relay.

This “power-to-the-relay-no-power-to-the-fuse-unless-I-jump-it” is giving me nightmares. I just doesn’t make any sense.

There are no error codes (when I read the codes, the light blinks for .5 sec, off for 2.5, on for 2.5 and off for 2.5 in a continuous cycle).

I’ve heard it could be the crankshaft position sensor but I also heard that would give me a code.

Any ideas? What is that big relay opposite the crash alarm relay? Tonight I will test the sensor if I can find it and check for spark and fuel pressure. I have TIS disks coming in the mail. I need an answer before I run out of money. Any help is much appreciated.