Running Rich... - BMW Forum

Charleston Chu · 10-10-2005, 10:04 AM

Last year I installed a new cold air intake and modified exhaust on my 1989 325ix... Since then, I have found to be running too rich. YOu can smell it. I was considering changing the O2 sensor but they are damn expensive. On that note, I was also considering modifying one of those half looking superchagers for and E36 to fit into my car... sketchy I know... but I'm all into the projects for this car. I guess what I am trying to find out is... is there anything that I can do now to lean out the air/fuel mix? Thanks in advance for your help, eh!

Chuck

DJProfessor · 10-10-2005, 12:05 PM

check the line to your FPR.....generally speaking the FPR are the cause of the rich running condition.....if she runs good when cold not when up to temp then i would be blaming the 02 sensor....

Hamfisted · 10-10-2005, 01:58 PM

Yeah I would look at the fuel pressure regulator and see if it's got a hole in the diaphram letting fuel get past. See if you smell any fuel in that vacuum hose that's connected to it. The other possibility might be leaking fuel injectors. The O2 sensor doesn't come in to play till the car is warmed up and you'll usually get the Check Engine light for that problem.

Mike

Charleston Chu · 10-10-2005, 03:35 PM

I used to get the check engine light if it ran for a really long drive... like 8 or 10 hours straight... but then, any car might... Where is the FPR anyways? I have looked but unable to find in the past. Thanks again

Chuck

Hamfisted · 10-10-2005, 04:51 PM

No, you shouldn't get a CEL light after 8 or 10 hours of driving, it means something is out of whack. How old is the O2 sensor? If it's got more than 60,000 miles on it replace it. The fuel pressure regulator (FPR for those cool guys...) is located at the front end of your valve cover on top of the motor, easy to see, easy to reach. It has a fuel line coming in one side and a vacuum line coming in the other side. If the vacuum line smells like gas it means the diaphram in the regulator is ruptured and the whole thing needs to be replaced (about $60 from BavAuto...p/n - 0 280 160 226 ). If it doesn't smell like gas then it's probably Ok. Honestly though, when these things fail you start blowing smoke out the tailpipe.

Here's your "FPR" ....

Mike