Fluctuating RPM's - Bimmerfest - BMW Forums

Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E21 (1975 - 1983)

E21 (1975 - 1983)

Thread Tools Display Modes
Old 03-14-2009, 11:19 PM
gleary2272 gleary2272 is offline
Registered User
Location: Colorado Springs, CO
Join Date: Mar 2009
Posts: 1
Mein Auto: 1980 320i
Fluctuating RPM's

Hi all, I'm new to this site as well as a new Bimmer owner. I have a 1980 M10/E21 5 speed w/190k miles. Overall, it is in good shape and running order except for an idle anomally. On start up, the RPM's fluctuate from about 700-1100 in idle. On acceleration and running at speed, it is fine, this just happens at idle and happens until it is at full operating temp. It also belches a little bit of blackish smoke at start up and only lasts around 30 seconds then goes away (which normally means a rich fuel/air mixture). I'm thinking that this may be an old O2 Sensor. Please let me know before I spend $70 or so on a new sensor, or if this is totally off the wall and I need to take a new road to fix this as this is my only complaint with this classic.
P.S. I do live in Colorado (above 6500ft), could this have something to do with these issues as well?
Reply With Quote

See More Related BMW Stories

Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E21 (1975 - 1983)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -7. The time now is 02:19 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001- VerticalScope Inc. All rights reserved.