My brother has a much loved '87 E28 520. Done nearly 250,000 miles. He recently had to change the head gasket (and have the head planed) after a hose blew and it overheated, but it's now running better than ever. Except that the idle speed is far too high. He has the Haynes manual - but that's as much help as usual. I think it has the L-Jetronic system - the warm up fast idle is by a vacuum valve. The AFM has an adjustment screw on it - but on other cars with this system that's for the idle mixture? My first thoughts was an air leak somewhere - but it has just about the most tortuous plumbing I've ever seen. We tried wiggling all the hoses we could get to, and removed the AFM and trunking to check that, but all fine. Any guesses?
- posted
13 years ago