Hi everybody-
The other night I was out in my garage messing with the new radar detector. Over a period of about a half hour, I turned the key on and off (to the accessory position) probably a couple dozen times. Towards the end of it I got a surprise. I turned the key to the on position and I heard a strange noise from somewhere under the car. I don't know if it was front or rear. The noise sounded similar to a small air compressor and lasted only a couple of seconds. (It stopped by itself.) Does anyone know what this was? Bad thing or normal? My first thought was fuel pump, but I don't know.

Along the lines of a fuel pump issue, I've noticed that my brick tends to have "good" and "bad" days. Sometimes it wants to go like hell, sometimes it feels like I'm towing something. My precision butt-dyno is telling me that something is up. I just don't know what, and don't want to jump to any conclusions. I first noticed the performance issue months ago but passed it off as no big deal. Any advice on either or both of these matters would be greatly appreciated. Thanks.

Tim

--
Tim Smith '85 745GLE M46w/84k. Currently infested with gremlins.

In my car it was the acummulator for the vacume actuated valves in the air system. For me it does it every time i turn off the car. Decided not to worrey about it as it does not seem to do anything other then make a hissing sound when i turn the car off. Hope this helps

Hey Hey!
It was your fuel pump, the main fuel pump. Not exactly SURE why it does that every now and again, but the computer sometimes must think the pump needs to be primed. Thats all i can think of. It isn't supposed to start pumping till it receives an ignition signal. Maybe our volvo computers are in denial because they were put into a volvo? (At least thats what people i know would say!) Nah, it's just the fuel pump starting. For some reason, unsolved mystery...!
Az

Not sure which computer's used in the 700 this year, but all it takes is a glitch on the ignition line to get the fuel pump relay on for a second even if its the one built into the relay.

Tim: easy enough to eliminate the antenna as a 'gremlin:' turn the radio OFF before you put your key in the ignition! Every now and then I,too, get a strange noise at start-up, and haven't done a single thing about it; it's almost a mechanical 'moan' from the general under the hood in front of the driver area. Air pump? Oil pump? Dunno. No warning/idiot lights, no failure to start, only lasts 2 or 3 seconds, doesn't seem to affect anything. So, if it ain't broke, I ain't fixin' it! BUT: I would like to know what it is, for peace of mind and general knowledge.

Peace of mind and general knowledge are all I'm after. The sound that you describe sounds a lot like what I heard...a 2-3 second mechanical moan that doesn't seem to be malignant. I know for a fact that it's not the antenna mast. That's a sound that I've grown quite accustomed to, and this was different.

I'll take it as a good thing that nobody has chimed in with a horror story (yet). Thanks for all responses thus far.

Tim

I vote Fuel Pump. The antenna does sound similar, but since you said it came from under the car....

Might that noise have been the auto antana raiser? it definatly sounds like that, and only runs for a couple secconds and cuts of on it's own.

Justus
--
Proud owner of a '96 960 & '90 740 turbo