Fuel Pump Drama

Ok, I’m stoked to take drive in D90 this morning, it died upon startup. Fired it up again and did not hear the fuel pump kick on to prime the system. I pulled the FP fuse, not the FP relay, and it fired up!
As I pulled out of my garage, it died. Pulled the FP fuse again, reinserted the fuse, it started ( could hear the FP kick on) then died. Again I pulled the FP fuse, reinserted the same fuse (it was not blown, it was good), I fired up and I pulled into my garage...went on with my day.
Two hours later, I started it and I fired up 10 times with no issue ( in my garage)...good times; however, I don’t trust it now...

Another note, this same thing happened about 2 years ago and it hasn’t acted up since...until now...

This is a stock 1995 NAS D90 with 103k miles.
It’s a weekend toy, not driven daily; however, it in excellent condition mechanically other than this fuel issue.
The fuel pump in original...I haven’t check fuel pressure yet, it on my list. Should I just bite the bullet and replace the fuel pump? Go figure, it’s got a full tank of gas too...
Does sound like a funky relay.

I'd diagnose it first. The circuit is straight forward. if I recall correctly; Battery -> Master fuse (in engine bay) -> FP Relay (pin 87) -> Fuse 20 -> Inertia switch -> FP.

The white/red wire into the relay (if i'm recalling correctly) is from ignition switch and triggers the relay on/off. Brown is main power from Master fuse. 87a is power to O2 sensors.

Bust out a meter or probe and see if signal is making its way through. Keep in mind, when you cycle the key, the FP relay will power up for a few seconds before turning off.

If all the wires check out and are each end is talking to each other, jiggle wires. I've had phantom issues come back due to bad wires. also check grounds.

Hope this helps. Coffee has not kicked in yet...


Well-known member
Honestly, you should keep a couple silver relays in the cubby box. In general, I replace them and put the originals in the cubby as spares.

A quick back to check if it’s the relay, I believe you can switch the two and the pump should run if the relay is bad (I forget what the other one is for, ECU or something).

You can also jump the relay to get home. Again, I keep spare so I have never had to do either hack myself.
My understanding is that the other relay is the ECU (sometimes referred to as fuel injection), so it won't run if you swap the relays and the FP relay is bad, but like you said, you should hear it turn on with the key..