Possible Repost: Need Help! - 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

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 09-03-2015, 05:15 PM   #1
Registered User
Join Date: Sep 2015
Location: NorCal
Posts: 1
My Ride: '99 323i e46
Possible Repost: Need Help!

Hi everyone, about two years ago I purchased a '99 323i with over 250k on it for about $3700. I know I bent myself over but i'm past that. Recently I've had an HGF and the car would overheat relentlessly. It overheated multiple times for a good length of time so I'm fairly confident the head was warped.(I didn't really care because the engine didn't have much life left) After this predicament I decided that I would buy another e46 that was in a rear end accident but the engine ran perfectly and only had 175k on it. (Quite a bit of miles, however nearly 100,000 less than mine) I purchased the car for $500 which was a steal. About a week later I had my mechanic work on it and he swapped out the engine within two days. At this point you're probably thinking "sweet, he got his car running again." Yeah, well maybe not so much, it idled really rough and it was throwing off fuel trim codes and misfiring codes for every cylinder along with fuel sensor codes. at this point I thought "no big deal it drives nicely it just idles rough maybe we can figure out why its idling bad." Well my mechanic decided that he was gonna switch out the wiring harness from the old engine(323i) with the wiring harness from the new engine(325i). BAD IDEA! Now the car won't run at all and the EML light came on(because my mechanic was screwing with my throttlebody) and not even the stealership wants to deal with it, even though I believe its just the wiring harness not making a full connection with the new engine, BMW explicitly mentioned that "We can't even communicate with the car." wouldn't that indicate that all it needs is a new wiring harness? Any help or advice would be much appreciated please don't let the replies to this post get too off topic as i'm in distress and not entirely sure what I should do. Some might say get a new car but that is NOT an option as we are still paying off this bimmer. Please do not point out where I have gone wrong because i'm fully aware of every misstep i've made and i'm totally aware that what i've done may not have been the smartest/easiest method to getting a running e46.

Thanks again for any help or advice you can throw my way!
Gibbeh is offline   Reply With Quote
Old 09-12-2015, 02:17 AM   #2
Registered User
Join Date: Sep 2013
Location: Tulsa, OK
Posts: 1,502
My Ride: 2002 330Ci Conv.
Noticed you haven't received any responses. Breaking your initial post into paragraphs may help others better follow/understand your situation.

Here are the cliffs so others may better assist:

1. Purchased a 1999 323i with 250,000 miles in 2013 for $3,700.
2. Two years later (present day), engine is replaced due to multiple severe overheats.
3. Replacement engine is from a 325i (year unknown) with 175,000 miles purchased for $500 (rear end accident).
4. After engine swap (performed by shop), car is now suffering from rough idle, fuel trim, misfiring, and fuel sensor codes.
5. In attempt to fix, mechanic replaced original wiring harness with one from new engine (see #3).
6. Car does not run now, EML light is on, and second opinion from BMW dealership is, "We can't even communicate with the car."
7. OP is still paying off original vehicle, so does not want to buy new car.

Given the current information, if it were me, I'd do exactly what you don't want to do in #7.

Hope others can help!

DIYs help you save money with repairs; let www.bmwpnpc.com help you save money with the parts.

Last edited by SilberVogel; 09-12-2015 at 12:12 PM.
SilberVogel is offline   Reply With Quote
Old 09-12-2015, 08:45 AM   #3
OEM ///Member
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 24,654
My Ride: 330CiC, M5, X5, E93
Some quick comments, I have not put a LOT of thought into this and I do not have the 323 experience that I have with the 325/330.

So a few comments:

When the car used to run, my guess is either the swap used the fuel rail from the 325 and/or the O2 sensors were swapped. There is a BIG difference between the 323 and 325 regarding the fuel delivery. The 323 has the fuel pressure regulator mounted on the front of the fuel rail and it is actually vacuum controlled, meaning the engine vacuum changes the fuel pressure. The 325 DOES NOT have vacuum controlled fuel pressure (no I do not need a flame suit and anyone that tells me the 325 has a vacuum hose connected to upper intake boot is WRONG, it is a VENT hose that supplies a FILTERED ATMOSPHERIC vacuum reference to the FIXED pressure fuel pressure regulator). DO NOT QUESTION THIS!

So the proper way to configure the 325 engine in the 323 with the 323 controls would be to use the 323 fuel rail, assuming it would fit.

I also think the earlier 323 may have had a throttle cable vs. drive by wire???? Not 100% sure about this, just one more complication that needs to be clearly understood.

As for the O2 sensor wiring swapped Bank to Bank, this is a VERY common problem but also a VERY simple fix.

Now, the engine is not running and the DME cannot be communicated with since the wiring harness swap. Again I do not know the 323 as well as the 325/330. The first thing that comes to mind is the fact the 1999 model has the round 20 pin connector under the hood with a jumper for the ODBII port under the dash. Unless the wiring for the OBDII was properly configured, at a minimum the other modules in the car cannot be read from the under dash connector. I also am not sure the 325 harness will route the OBDII signals to the under dash connector.

For the engine not running, first thing to do is check fuses. Then verify fuel, spark and tach signal. You need to watch the tach while cranking and make sure it is registering 100-150 steadily. Starting fluid can be used to rule out fuel problems. A good 2 second burst of starting fluid in the MAF opening and the engine should start and die if there is a lack of fuel. Checking for spark, use normal methods.

This all assumes there is no problem with the EWS playing into any of this.

What year was the 325? There are some variations and the later 325 are very different than the early 325.

This is a very quick overview and I did not put a lot of thought into all of the issues, but this is what came to mind initially.
Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
jfoj is offline   Reply With Quote
Sponsored Links
Old 09-12-2015, 11:14 AM   #4
Registered User
Join Date: Oct 2008
Location: Los Angeles, CA
Posts: 3,139
My Ride: 05 330i ZHP/MT
Yes, this sounds like an M52TU / M54 swap issue.
The M54 harness is made for drive by wire.

People either do a full swap complete with engine, DME, EWS, etc, or install the old air intake and fuel delivery on the new engine.
Megalocnus is offline   Reply With Quote
Old 09-12-2015, 01:52 PM   #5
Registered User
Join Date: Jul 2012
Location: upstate NY
Posts: 1,593
My Ride: 2002 330 cic
Consider it a learning experience
dknightd is offline   Reply With Quote

bmw, e46, engine swap, no start

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 05:50 PM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.