new user needs help rough idle

[eddiem27]

where should the needle be sitting on the tacho of my 1993 316i mine stays around 750 and is very lumpy i have not had the car long and need some help the car starts ok does not stall runs very well but the idle seems very rough and there is a little flat spot around the 2500 range which soon clears but can be very annoying.is this an injector thing or something else i dont think it needs a service yet its got a few months to go it has a full bmw history and has been looked after and does anyone know where i can get a new glovebox door or how to repair the one i have one hinge is broken.

[KC Ron Carter]

To check the ignition system raise the hood after dark and look for crossover sparks.

There is a manufacture provided service procedure to flash the combustion chamber with steam to force the carbon to break free from the piston face and valve face.

With the engine at normal operating temperature and approximately 2000 RPM, allow the engine to ingest by a vacuum hose 12 oz soda can of water.

A puff of steam and the carbon is gone.

The ChevRON TechRON is to clean the back side or tulip of the valve
and all components on the fuel path, of varnish.

http://www.chevron.com/prodserv/fuels/techrongas/

You can use as often as needed.


BMW injectors are phased so the fuel is sprayed on the back of the valves 50% of the time. That leaves a lot of varnish on the back of the tulips and stems.

Later,

[Nels Ferre]

Hi,

I had the same problem with my 89 BMW 328is. I suspect a build up of crap on the valves as well.

I tried a bunch of stuff, including different brands of super unleaded (Chevron included) and liked Z Max the best.

www.zmax.com

Used as directed every other oil change, and my car runs great. Costs about $20 per treatment.

Hope this helps.

Nels

[eddiem27]

[quote=Nels Ferre]Hi,

I had the same problem with my 89 BMW 328is. I suspect a build up of crap on the valves as well.

I tried a bunch of stuff, including different brands of super unleaded (Chevron included) and liked Z Max the best.

thanks for the reply i will give it a go ive visted the website looks like good stuff cheers .