fuel pump running with key out?
 

Okay guys, im at a loss for ideas here.

Last november my car took a **** on me, as it has done a few times in the past. It killed my brand new battery one day, i boosted it, all was well for a day or 2. Then it happened again and wouldn't start. It had done it before the same issue, which rectified itself with little help from me. This time though I could hear the fuel pump going and some humming from under the hood. I swapped a few relays trying to isolate the problem and ultimately ended up seeing smoke coming from the harness box. My frustration hit an all time high and i shut the hood and let it sit for the next 4 months.

Now, I had a hacked up engine harness from the guy who I bought the motor from, so i attributed it all to that...
so this weekend was the first chance I got to do anything about it... i spent all day replacing the wiring harness...


So i got it all back together and hooked up the battery and once again, with no keys in the ignition... the fuel pump still runs by itself and that humming from under the hood is still there.

I started pulling fuses, one by one, to see if i could isolate the problem area. That did nothing.
I have a pile of used relays laying around, so i started by seeing if any of those were the culprit. Nope, relays are good.

Ultimately, I left one of the main relays (3rd one, closest to firewall, under the black cover, that neighbour the DME and Fuelpump relay) unplugged and connected the battery. No noises to be heard with this one out. A quick check in my bentley says this relay controls the oxygen sensor heater or something like that....now that was a problem area before i swapped harnesses but i assumed the new harness would cure this problem but it hasn't.

Ive googled and looked at alot of things pertaining to the same issue on other vehicles, and Oil Pressure sender switch comes up often...? do you think that is likely, or something else?

Does anyone have any ideas for me? Im out of ideas and I dont just want to throw $1k worth of parts at it and end up in the same boat.

Thx
Ryan

Best thing to have done is get a good harness and never swap random relays, as theyre not all the same. Are you sure its the fuel pump thats running? Dumb question, i know, but there are a few other things that will continue to run after the engine has been turned off and the key removed.

Removing the fuel pump relay or the fuel pump fuse itself should shut it off, plain and simple. If it continues to run, there are still more wire discrepencies.

Even though it might be correct, have you thought about your AA reflash? Did you ever have it running prior to your installation of software or has it always ran from an aftermarket tune? Thought about installing OE software just to test?

I got a good harness and the only time I swapped random relays was back in November... This harness came with main relays still attached. I didnt exactly "swap" anything random per say, but I tried the same colored ones in different places.

I got a good harness, and installed it last night.

Ive been running my swap the entire time with the AA tune because I had to have EWS deleted.

Im positive its the fuel pump, as when I pull fuse #18, the fuel pump fuse, it stops.... but the "humming" noise is still there - sounds just like an electrical draw, but a little louder and its coming from either under the manifold or the alternator, can't quite narrow the sound down because its a constant buzz. The only way to kill both is to pull that 3rd relay under the black cover, as mentioned in my OP.

I have replaced all the relays as well, with spares that i got from Zboot.

and i should mention, this problem occured back in November before touching any relays or fuses at all.

Even as the same colors, the relays arent the same. There are schematics on the side of them which shows what happens when activated. I had a friend do this on my car a few years back, caught my engine harness on fire.

As far as the humming goes, unplug your idle control valve, see if the humming is still there.

Ive been checking all the numbers on the bottom of the relays... 30,85,86,87etc before swapping them out on the new harness.

My car is at my moms place and I wont get down there again til Wednesday, so just curious as to why do you think it could be the ICV humming? It does sound like the noise is coming from that general area, but what could that have to do with the fuel pump and fixing my problem?

The icv is a pretty loud pump and will always run anytime the key is in the ignition, which is outside of your problem, but can be associated with the noises.

Also, the schematic, on the side of each relay, is the best way to see what the relay does, as the bridges could be completely different though look the same by just looking at the underside of the relay.

If you do a search on bfc, there are a few threads pertaining to running pumps, sensors, relays, etc. as well as answers to why and where.

hey blue, you were right as usual... the other noise is the ICV.

Now what? any ideas?