Running lean for a long drive safe? - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

Thread Tools Search this Thread Rate Thread Display Modes
Old 09-29-2015, 06:30 PM   #1
Registered User
Join Date: Mar 2015
Location: Davis, CA
Posts: 5
My Ride: 2000 323Ci
Running lean for a long drive safe?

Hi guys,

First, a little back story. I'm from California but I spent this summer in Michigan working on some stuff for Ford (they're funding my PhD). Anyhow, a couple of weeks ago my 2000 323Ci SES light lit up and it's throwing the P1188 and P1189 codes. I replaced both pre-cat O2 sensor since they were probably the originals (the car has about 115K miles on it). I also found a hole in the intake boot and replaced both the lower and upper intake boots. While I was down there, I also cleaned the throttle body, ICV and MAF. However, none of this fixed the problem. I also replaced the battery since it was pretty old and it was starting to show symptoms of a bad cell. Mind you, I've had to do all of this while away from all my tools back home.

This brings me to my question. I'm almost 100% sure that there is a vacuum leak in the CCV. Unfortunately, I don't have the time/tools to fix the problem since I need to drive back to CA this Saturday. I'm looking at a 2300 mile trip, mostly highway (70-80 MPH). Do you guys think that I can get the car home safely without damaging it? The car is running lean and it seems like the SES light only comes on at highway speeds. Any input would be greatly appreciated. Thanks!

I should note that the car runs and idles just fine. There is no shaking/vibration during take offs nor are there any power losses while at speed.

Last edited by inert1a; 09-29-2015 at 06:34 PM. Reason: more info
inert1a is offline   Reply With Quote
Ads by Google

Guests, get your FREE membership to remove this ad.
Old 09-30-2015, 08:44 AM   #2
Registered User
Join Date: Jul 2008
Location: USA
Posts: 6,181
My Ride: 2001 330Ci
The codes come up with a fuel system malfunction. Is the fuel pump original? How many miles since the fuel filter was replaced?

I recommend that if the fuel pump is original that you replace the pump, the pump gasket and the fuel filter. Otherwise you could be stranded when the fuel pump dies.
markusmarkus is offline   Reply With Quote
Old 09-30-2015, 11:10 AM   #3
Registered User
Join Date: Mar 2015
Location: Davis, CA
Posts: 5
My Ride: 2000 323Ci
I'm guessing that the fuel pump is the original. I haven't replaced the fuel filter since I bought the car which was about 20K miles ago. I've gone ahead and ordered a fuel pump and filter. I'm not sure if I'll have enough time to install them but I guess its better to have them on hand if they do fail on the drive back.
inert1a is offline   Reply With Quote
Old 10-01-2015, 04:25 PM   #4
Registered User
Join Date: Jun 2010
Location: CT
Posts: 2,138
My Ride: 2001 325i
If you have a larger screwdriver, hammer, and one or two hose clamps (don't remember offhand how many you need), you can change the fuel pump by yourself. Not optimal, but it can work that way. Fuel filter, you probably want to have a few hose clamps, as some break when remove them (sometimes OK, sometimes not). Two clips/clamps to close the two rubber hose connectors to the fuel pump can help too, although if you don't mind working around a little spilled gasoline, you can get by without them. Get a new fuel pump gasket too. Some people reuse them, however, they aren't expensive. I used a BMW gasket when I changed my fuel pump. Note how the gasket goes on when you remove the fuel pump, and remember to put the gasket on the body before putting the fuel pump in, and don't put the gasket on the fuel pump itself to install.

Last edited by Sansho; 10-01-2015 at 04:26 PM.
Sansho is offline   Reply With Quote
Old 10-01-2015, 06:44 PM   #5
Registered User
Join Date: Mar 2015
Location: Davis, CA
Posts: 5
My Ride: 2000 323Ci
Thanks for your input! The parts just arrived today. As you noted, the fuel pump is an easy install. However, due to my lowered suspension, I need a low profile jack to reach the fuel filter. At any rate, if something does fail on the drive back, I'm pretty prepared to to fix whatever needs to be replaced. I'll keep you guys posted if I get stranded or not. lol.
inert1a is offline   Reply With Quote
Old 10-01-2015, 10:10 PM   #6
Registered User
Join Date: Feb 2015
Location: Los Angeles, CA
Posts: 109
My Ride: 330i
If it runs fine, yes it's safe to drive a long distance. The computer is compensating for the extra air getting in by adding extra fuel, thus keeping the air/fuel ratio at stoichiometric 14.7:1. When it starts to run shitty, it has maxed out its ability to compensate.
50sKid is offline   Reply With Quote
Old 10-03-2015, 07:28 PM   #7
Registered User
Join Date: Mar 2015
Location: Davis, CA
Posts: 5
My Ride: 2000 323Ci
Made it through the first leg of the trip without any problems. Stopped in Stuart, IA for the night. I replaced the MAF sensor before leaving, reset the codes (P1188 and P1189) and 600 miles later, no SES light! Long term fuel trims are now well below 10% so everything seems to check out. It seems like the old MAF sensor was the cause of the problem. Even though I cleaned it with CRC MAF cleaner, it was still measuring incorrect airflow readings throwing the fuel delivery system out of whack. I managed to get the Seimens MAF sensor from Amazon for $200 last minute. Glad I ordered it! Thanks again for all your help guys. I still plan to installing the new fuel pump/filter and full CCV once I get home.
inert1a is offline   Reply With Quote
Old 10-03-2015, 07:44 PM   #8
OEM ///Member
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,199
My Ride: 330CiC, M5, X5, E93
Cleaning a MAF is basically a waste of money for the most part. When MAF's start to degrade, they under report the airflow, thereby causing Lean codes once the Fuel Trims hit +10% or higher.
Solve your misfires, lean codes, rough idle -

Fuel pump failures -

Temp Info -

Hidden OBC Menu - Check Voltage, Temp, Fuel Level -

E46/E39 GM5 Door Lock Info -

Lower hose temp switch O-ring - BMW #13621743299
jfoj is online now   Reply With Quote

ccv, lean codes, p1188, p1189, vacuum leak

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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
Censor is ON

All times are GMT -5. The time now is 06:32 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.