Posted by Don Daynes on March 05, 2001 at 18:13:59:
In Reply to: Re: FS: '79-'81 528i Fuel Pressure Regulator posted by Troy Rudolph on March 05, 2001 at 17:12:01:
Peter posted the part number for the 3.0 bar pressure regulator as 0.280.160.213. The attached calculator says 3.0 bar = 43 psi and 2.5 bar = 36 psi.
All this talk of pressure regulators is hitting me where it hurts. I am in the middle of doing battle with my "stock" 81 528i and the Calif. smog laws. It passes the CO test (both 15 and 25 mph)and fails the NOX test miserably (only at 25 mph). The test also indicated 23:1 air fuel ratio. I have richened up the AFM to the point it may pass smog, but something is still not right. The Split Second air fuel ratio meter now shows a slightly rich mixture at cruse (10 - 30 mph), abruptly changing to extremely lean as the mph is increased and mantained. Richening the mixture only seems to have move up the speed at which it goes lean. I also see no attemps by the system to "hunt". The lights are very steady. The change to lean is very abrupt. The driveability has never suffered and you can't feel any change when it goes lean. No telling how long it's been like this.
Question is. Is my fuel press. reg. bad? Pressure gage reads only 29 psi and it fluctuates (needle vibrates quickly) about 10 psi. Is that due to injector dwell time rapidly changing?