New 325ci starts day with two loud bangs in morning

[DennisM]

I just bought my wife a 2004 325ci, a beautiful car she loves. It is 2 weeks old and has about 500 miles on it. Early last week she told me it made a strange noise. I listened to it, and sure enough, heard two loud bangs on the first start of the morning. When I pop the hood and stand in front of the engine, I still can't tell where or what, but it sounds like someone in the engine block with a sledge hammer. The engine starts, runs 1-2 seconds, makes two loud bangs, one right after the other, and then runs fine all day long. It is an intermittant problem but I have heard it 4 or 5 times, and finally the dealer heard it.

The dealer is baffled, the car is in the shop for the second time, and the wife is crying.

Any ideas?

[Soupcan325i]

Have you run a CarFax on the wife? Maybe she is a lemon...

[The Roadstergal]

Any ideas?

Have you pulled the plugs and looked for signs of detonation? All I can think of that's consistant with the first start only and explosions is fuel getting where it shouldn't overnight... but I just have no clue about y'all's newfangled engines. ;) It doesn't happen if the car sits for many hours at work and is restarted? Does it sound like it's coming from the block or the exhaust?

But if the dealer can't fix it, he needs to declare the car a lemon and give ya a new one.

[barryf]

My wife's new 325cic has the same problem with 1200 miles on it. I have not taken it to the dealer yet - will be doing early next week. I will let you know if they find anything. It is not going to be easy as it only occurs that first start - does not occur again until it sits overnight.

[LeucX3]

Does it also happen at the dealer after it sits there overnight?

[DennisM]

The dealer has had the car all this week, and it happened there, in front of mechanics, God, and everyone twice. The dealer is saying he thinks its the injectors leaking, causing a backfire, and has ordered a new one(s). He'll pull the plugs Monday and look.

It has not happened at anytime other than when left overnight. It hasn't happened enough to me that I can tell exactly where the noise is coming from.

I've got my fingers crossed. I'll keep you posted.

Thanks for taking the time to reply.

[DN325CI]

My new 04 325Ci is doing this as well. In fact, I've had the car for nearly a year and it has 10,000 miles on it. It has always done this, but I quickly learned that if I turn the key to the on position but BEFORE starting I leave it on 15-20 seconds, it then starts fine.

I always wrote it off as the VANOS was out of position or something after a long off-time, like overnight.

Please share what your dealer learns.

Thanks!
Don

[DennisM]

Well, the dealer replace the injector and didn't solve the problem. The dealer is stumped. Any more ideas?

Thanks

[DennisM]

Okay, new news. The dealer called me today and said the rep was in, and there are at least 3 more new 325's in the shop with exactly the same problem. The BMW engineer's are thinking there's a bad batch of intake manifolds (are they really plastic?) and that they are replacing one of the several they have over the southern dealerships that are broke and we'll see. Maybe my new car will come home...this week is a milestone, folks..they've had it longer than I have.

[DennisM]

Well, folks, the new intake mainifold didn't fix one of the other cars, and a new camshaft sensor didn't fix mine. I've told the dealer to start looking for a new car for me...one free from manufacturing defects.

[LMC]

Mine doesn't do this (and I wouldn't think this would be just a Ci thing anyway) but Don's work-around is pretty interesting and might be a clue...

Has anyone else experiencing the problem turned the ignition on but waited to start?

My new 04 325Ci is doing this as well. In fact, I've had the car for nearly a year and it has 10,000 miles on it. It has always done this, but I quickly learned that if I turn the key to the on position but BEFORE starting I leave it on 15-20 seconds, it then starts fine.

I always wrote it off as the VANOS was out of position or something after a long off-time, like overnight.

Please share what your dealer learns.

Thanks!
Don

[mav63]

We have similar problem on our 2003 325i with 11,000 miles. We just purchased it used. It is an intermittent "engine knock" at cold startups. We tried doing the wait 10seconds for ignition turn on after placing the key to "on", but that doesn't help. We are taking it in this week and hopefully they'll fix it.

[DN325CI]

Mine doesn't do this (and I wouldn't think this would be just a Ci thing anyway) but Don's work-around is pretty interesting and might be a clue...

Has anyone else experiencing the problem turned the ignition on but waited to start?

I failed to mention that in my experience the two loud bangs sound exactly like the engine firing when a valve is open. Some of you with engine experience will know the sound.

So that's how I landed at the VANOS conclusion. Key in "on" position 20 seconds works every time. VANOS must reposition itself at start-up. My humble opinion.

Don

[sunilsf]

leaving a car overnight should not be deemed "a long time".... ironically, I don't think anyone should have to wait for 15-20seconds before starting their car (that seems like a "long time"). Okay, as a short-term fix, fine... but your dealer ought to fix this as it just sounds wrong!

[DN325CI]

leaving a car overnight should not be deemed "a long time".... ironically, I don't think anyone should have to wait for 15-20seconds before starting their car (that seems like a "long time"). Okay, as a short-term fix, fine... but your dealer ought to fix this as it just sounds wrong!

Agreed. It's on my list of several things I want them to fix at the first servicing.

Don

[mav63]

I am not as up to speed as I would like to be on the E46 BMWs but has anyone checked the timing on these cars. I am sure that it is electronically controlled but it sounds as if something is missing its initial calibration for the day on start up. Most likely the timing would be retarded by the Computer until the engine starts when it senses the engine is cold. Just a thought!

[LeucX3]

She bang! She bang! Then she moves, she moves! Oh baby...

[barryf]

Well, after 4 days at the dealer and draining the gas tank the shop manager ( and BMW ) recommended I put 87 octane in the car for 2 tank fulls and see what happens. Made the comment that the 91 octance doesn't turn over enough and could be getting bad gas - the 87 turns over more often so the tanks are refilled with new gas frequently. Then I can go back to 91 as by then the stations will have refreshed their gas w/o ethanol ( winter gas here in N.M ). He had 4 325's in the shop at the same time with the same problem. Stated that New Mexico is notorious for bad gas - and according to him so is Colorado. I asked him why this was occuring in other states - we can't be getting our gas from the same refinery. No answer to that one. I think they are stumped and don't know what is causing it. Will keep up-to-date on results.

[Patrick330i]

Well, after 4 days at the dealer and draining the gas tank the shop manager ( and BMW ) recommended I put 87 octane in the car for 2 tank fulls and see what happens. Made the comment that the 91 octance doesn't turn over enough and could be getting bad gas - the 87 turns over more often so the tanks are refilled with new gas frequently. Then I can go back to 91 as by then the stations will have refreshed their gas w/o ethanol ( winter gas here in N.M ). He had 4 325's in the shop at the same time with the same problem. Stated that New Mexico is notorious for bad gas - and according to him so is Colorado. I asked him why this was occuring in other states - we can't be getting our gas from the same refinery. No answer to that one. I think they are stumped and don't know what is causing it. Will keep up-to-date on results.

Whoa, that sounds like something out of an old Cadillac playbook. Drive the two tank fulls this weekend and if you have the problem Monday a.m., show up and give 'em hell!

Sorry this is happening to you guys. Must be incredibly frustrating. Good luck to you all.

[ChrisTO]

ouch....if innovation is suppose to make a car better...i'll settle for less innovation in a quality car like a Hyundai. :)

good luck and keep us posted.

[nickeltong]

Stated that New Mexico is notorious for bad gas - and according to him so is Colorado.

Colorado has a different gas mixture due to its higher elevation. Gas needs to compensate for lower Oxygen level. So did going to a lower octane level solve your problem? Keep us posted on your situation.

[Parump]

I am sorry to read about these problems. I am disappointed that a shop manager and BMW would suggest using 87 octane when the major refining companies conduct multiple quality assurance tests involving the sampling of mogas at many different locations in the distribution chain. In my opinion, the suggestion that a fuel quality issue is responsible for the problem is simply an excuse. I vote for an intermittent electrical problem that is difficult to diagnose and doesn't trigger an engine fault code . . .Well, after 4 days at the dealer and draining the gas tank the shop manager ( and BMW ) recommended I put 87 octane in the car for 2 tank fulls and see what happens. Made the comment that the 91 octance doesn't turn over enough and could be getting bad gas - the 87 turns over more often so the tanks are refilled with new gas frequently. Then I can go back to 91 as by then the stations will have refreshed their gas w/o ethanol ( winter gas here in N.M ). He had 4 325's in the shop at the same time with the same problem. Stated that New Mexico is notorious for bad gas - and according to him so is Colorado. I asked him why this was occuring in other states - we can't be getting our gas from the same refinery. No answer to that one. I think they are stumped and don't know what is causing it. Will keep up-to-date on results.

[shamilot]

ouch....if innovation is suppose to make a car better...i'll settle for less innovation in a quality car like a Hyundai. :)

good luck and keep us posted.

No doubt; I have a Hyundai ( 7 yrs. 120,000+ miles ) the only thing I've done with it is changed the oil regularly and other than routine maintainance as suggested by the manufacturer I needn't touch a thing! Sure a few small things are beginning to fall apart on it, (most recently I went to adjust the rear-view mirror and it came off ) but as far as the engine, trans, and drive train, etc., I'm looking forward to another 60,000+ miles w/out problems.
However, once my 325CiC arrives (mid-June) I don't suppose I'll be driving the Huyndai much if at all. Nevertheless, this post and the troubles reported by some members is of great concern to me. Even if it's 1/1000 I'm disappointed to hear the kind of run-around these BMW owners are getting from their dealers and the Manufacturer. :tsk:
In the owner's manual it reads: "The engine uses lead-free gasoline only. Required fuel: Premium Unleaded Gasoline, min. 91 AKI= Anti Knock Index" (whatever that means).
I was wondering, if you do use Regular gasoline wouldn't that be grounds for the Manufacturer to void their warranty?
My heart goes out to you.
Good Luck and I hope you find a satisfying and speedy resolution.

[DN325CI]

Well, the dealer just fixed this issue on my 2004 coupe Saturday. After three cold-start mornings, the banging/backfiring appears to be completely gone. Not even a stumble.

Repair comment on my service statement says "ERROR IN DME READ FAULT MEMORY, NO FAULTS STORED, REPROGRAMMED DME ACCORING TO SERVICE MEASURE 1220703, CLEARED ADAPTION VALUES, ALIGNED EWS AND DME".

Whatever the heck that means!

Don

[dorkus]

Repair comment on my service statement says "ERROR IN DME READ FAULT MEMORY, NO FAULTS STORED, REPROGRAMMED DME ACCORING TO SERVICE MEASURE 1220703, CLEARED ADAPTION VALUES, ALIGNED EWS AND DME".

Whatever the heck that means!


don't know much about engine computers, but based on my hardware experience it sounds like it was a bug in the engine computer's firmware... perhaps due to a bad batch of writes at the factory, or maybe even bad batch of flash memory. fortunately it was just a control problem, but i hope that banging did not cause any damage to the engine.

[Bandit]

Althought my car doesn't have the loud knocking, it does have troubles starting from a coldstart, which another member has told me probably is the fuel pump. I have a 2003 325i with 19500 miles. Any 2nd opinions would be appreciated, I was wondering if these intake manifolds, cam sensors or vanos etc could be related to my problem. Problem can be found here :
http://www.bimmerfest.com/forums/showthread.php?t=66473
thanks

[mav63]

Could it be true? We just filled up our tank with Shell (octane 93) and two days in a row now with below freezing temps and no knocking, coughing, sputtering in the morning at first start! Previously we had been using BP, but if this keeps up, Shell will be the rule!

[JonathanIT]

We just filled up our tank with Shell (octane 93)
Wow, we can't get 93 octane anywhere around here... except for some specialty shops for race engines. Wish my local Shell carried it!

--J.

[yamato]

I don't have any loud noise when I do a cold start. But I have another problem that it won't start or started but die immediately. I also found the trick to leave the key to ON for a few seconds before cranking. This works most of the time. But sometimes, maybe 1 out of 50, it still doesn't start the first time no matter it is a warm/cold start.

[my3rdbimmer]

sounds to me like a ECM issue to me.. in fact i am almost sure..