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Old Today, 11:31 AM   #1
B Evil
Registered User
Join Date: Apr 2014
Location: Ohio
Posts: 8
My Ride: 2003 325XI
Dreaded Misfires 2003 325xi

So I have been searching and reading the forums for years. Finally got around to replacing some of the common failure parts as I had been experiencing the common misfire, rough idle, hesitation, stall out when starting from a stop, etc. I have had several codes prior to replacing anything.


Whenever I would clear the codes, P1349 would seem to be the first one to come back. Would not always get each of these codes, but at least a few of the misfire codes.

So the items I have replaced. VCG, CCV (cold climate), Air Distributor O-rings, Fuel Injector O-rings, Intake Manifold gasket, Throttle body Gasket, Spark Plugs, Coils, Coil Boots, Fuel Filter, both upper and lower Intake boots, F vacuum connector (along with the small vacuum lines that lead from the Intake to secondary air pump, DISA valve, Cleaned Throttle Body, Cleaned MAF.

In doing all of this, had noticed several of the hoses were cracked and detoriated, DISA flap was broken, plugs and coils appeared to be original. All fairly reassuring this was going to help solve the issues given the shape and condition of the parts I was replacing on a 12 year old car with 170k on the clock.

Once I got everything put back together, she hesitated on the 1st start up, which I chalked up to building up fuel pressure and vacuum again. But now that she's been running for a few days, still have misfire codes coming back. These were the first set of fresh codes.


After these were cleared, ended up with these on the next trip.


Started to wonder if these issues could be caused by a faulty fuel pump. Over the years prior to doing all of this work, there were a few occasions of extra long cranks where it just did not seem to be getting fuel. But then she would eventually fire up and run ok. But having this in the back of my mind, decided to check the pressure at the rail. This was after the car had warmed up a bit, but got a steady 50 to 51 PSI. After sitting for an hour, the pressure still ready around 48 PSI.

So I figured I could rule out the pump. But left the gauge hooked overnight so I could check again first thing this morning. When i started her up this morning, the pressure only went up to about 46 or 47 PSI.

So... question is, could this be signs of a faulty pump? And if it was a faulty pump, could this be the reason for the misfires, hesitations, rough idle, etc?? Any other thoughts as to what the cause could be??

Thanks in advance for any help in solving this mystery!! It has me ready to roll her down a hill. Which, if any of you guys knew me, how many different 3 series I have had over the years, and how much I love my BMW's, getting to the point of rolling her down a hill only begins to describe my frustration...
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Old Today, 11:45 AM   #2
Registered User
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 12,553
My Ride: '06 330CiC, '03 M5
First 2 links below in my signature.

Freeze Frame and warm idle Fuel Trims are helpful here.

Search YouTube for Scotty Smoke Test. Do what Scotty does and/or build a tester like one from a related video.

If you plan on keeping the car, I would replace the fuel pump, it WILL fail at some point and they do soft fail as well.

Also understand that even replacement CCV hoses may be leaking because they were not fully snapped or an O-ring missing. Smoke testing is best to find the problems you assume are not there.

Also seeing power brake boosters failing and they seem to be failing more often in the xi for some reason??

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, Temps, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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

Lower hose fan switch O-ring - BMW #13621743299
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