520i electrical/power problems

[marvellousmee]

Hi there, I'm a newbie on these forums and actually a bit of a novice in the technical areas of BMW (although very much an enthusiast) so I'm grateful to have discoverecd these forums.

I seem to have 2 problems with my 1990 520i that I'd like to sort out and I'm not sure whether the two are related.
1) There seems to be some sort of electrical problem occurring, several things have happened and then miraculously sorted themsleves out like the interior lights and one headlight not working then working again & the fuel gauge does the same. I took the battery out and charged it off the car but it drains again if I don't use the car for a few days.

2) Engine power has just become a problem. The car seriously lacks power and the engine sounds kind of rough. I'll accelerate and the power won't kick in unless I really get the revs up and then it'll drop out again. I was travelling on the motorway yesterday and the power was dropping in and out all over the place. I'm seriously concerned about this and am worried about doing permanent damage to the engine

Can anyone give me advice as to why these things might be happening and if the two problems are related. Thanks.

 

[tangofournil]

Me too. I have a 520 SE AUTO ESTATE and it pops rear bulbs with alarming regularity (like, fortnightly). Also revs to 1500 at idle (occasionally) and seems to take ages to come down.

It's a 1999/T and has done 136,000 miles. Regularly serviced.

Has also developed a non-electrical problem - rear wiper linkage (the bit that sits in the glass tailgate) has seized. Anyone got any ideas?

 

[bahnstormer]

@marv - if your battery isnt holding its charge either its dead and tired
or there is an abnormal drain on the system somewhere - either a short
or ground....any aftermarket modifications to the stereo or anything like
that? look around for shoddy wiring done by previous owners

@tango - 1500rpm is approx what it holds to warm up the engine on a cold start...
it may tho be something to do with some sensors...sry not much i can help with
=\

 

[marvellousmee]

Thanks for the reply bahnstormer. I've had a look at the wiring behind the dash and there seems to a nasty little botch job where the stereo is concerned. So I think I'll take it out and do a proper job. I'm also thinking that the battery may not be big enough for the car, it certainly looks to small for the tray.

So would an electrical problem or dud battery affect the engine power dramatically? This is what I am most concerned about really.