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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > O2 sensors or Vanos??



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      09-18-2024, 09:55 AM   #1
c131frdave
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O2 sensors or Vanos??

I have a 2007 335i that was in storage for several years. My son turned 16, so we brought it out of storage and all was terrible. At least two fuel injectors were bad, they were clicking badly and I had all kinds of trouble codes related to injectors.

The old injectors were all -1, so I replaced all of them with newer ones and that seemed to solve the problem. It runs smooth with no faults.

However, after it warms up, it starts to misfire and lag. It's not a misfire like when the computer shuts down cylinders to protect the engine, but actual loss of power. It happens after driving about 5 miles. It stays smooth at first under normal throttle, but under heavy throttle it has low power and pretty bad turbo lag and boost cutout. The longer you drive it, the worse it gets until the computer starts shutting down cylinders.

Since it runs fine when cold, I'm thinking it is the 02 sensors as it runs in open loop when the sensors are not hot enough to work, however the boost issues make me think maybe it's the vanos. Has anyone else seen this?

The gas is 3 years old, which also may be a contributing factor. Unfortunately we filled the tank before putting in it storage. I may syphon some of it out and put in new. Anyone know of a good gas treatment additive?
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      09-19-2024, 01:39 AM   #2
swellengear
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Any codes? Vanos solenoids can get sticky if sat for a long time. Might be worthwhile pulling them out, and giving them a good clean. I would also get the old fuel out.
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      09-19-2024, 10:54 AM   #3
c131frdave
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No codes until it gets bad enough for the computer to start shutting down injectors. It takes about 5 minutes of boost lag (or no boost in and out) before it starts "misfiring". I think I'm going to replace both O2 sensors and clean the vanos valves as well.
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      09-20-2024, 12:56 AM   #4
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Did you code in the newer injectors with the values from each injector to the car? When you say newer injectors can we assume you bought used injectors and not brand new index 12s?

If used injectors, did you change out the seals and decouplers?

edit: also you probably won't be able to siphon fuel out thru the filler neck. You will likely have to remove the seat and remove either the fuel pump or the regulator and use a hand pump to remove that old fuel. You really should have done that before replacing the injectors because 3 year old fuel can do a real doozy on the fuel system.
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      09-20-2024, 11:57 AM   #5
c131frdave
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Yes. I coded the new injectors. I actually bought "new" -12 injectors and found out they were counterfeit. I installed them and then the ECU blew. I sent it to BoostMonkey and they found out that the numbers for my -12 injectors were all counterfeit, which is why the mosfets blew. They replaced my ECU and I replaced the injectors with known working injectors out of a different car. New seals and decouplers. There is no sign of leaking at all.
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      09-28-2024, 03:24 PM   #6
c131frdave
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My son and I cleaned the Vanos valves today and the stuttering boost is gone. They were pretty dirty, but looked like new when we put them back in. However, the car is still sputtering when it warms up. It runs like a champ for about 10 minutes after a cold start, but then it starts sputtering when it warms up. No codes! When it idles, it misses a cylinder every 2-3 seconds. When you drive it, it is missing one cylinder (probably) constantly, but again, no codes. I was going to replace the O2 sensors assuming that when the computer went into closed loop one of the oxygen sensors was reporting bad data, however I have no O2 codes. So maybe spark plugs? If a coil goes bad you would get a code, right? Any ideas?
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      09-28-2024, 06:51 PM   #7
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Quote:
Originally Posted by c131frdave View Post
My son and I cleaned the Vanos valves today and the stuttering boost is gone. They were pretty dirty, but looked like new when we put them back in. However, the car is still sputtering when it warms up. It runs like a champ for about 10 minutes after a cold start, but then it starts sputtering when it warms up. No codes! When it idles, it misses a cylinder every 2-3 seconds. When you drive it, it is missing one cylinder (probably) constantly, but again, no codes. I was going to replace the O2 sensors assuming that when the computer went into closed loop one of the oxygen sensors was reporting bad data, however I have no O2 codes. So maybe spark plugs? If a coil goes bad you would get a code, right? Any ideas?
Hi, I have the same Problem. Cold start is fine. After warm up misfires. Did u fixed ur car?
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      10-01-2024, 01:10 PM   #8
c131frdave
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Quote:
Originally Posted by tobiasgt View Post
Hi, I have the same Problem. Cold start is fine. After warm up misfires. Did u fixed ur car?

Not completely yet. Cleaning the Vanos solved the turbo issues, but the sputtering continues after it warms up. I have new plugs and coils sitting in a box on the doorstep waiting for me to come home from work and install them. If that doesn't work, I'll change the O2 sensors. I'll post here if the plugs and coils fixes it.
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      10-02-2024, 07:48 PM   #9
c131frdave
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Update. It is running much better. I started changing plugs and I found plug #6 was drenched in gasoline. I have my old injectors, only one of which is bad, so I put a "good" one in #6. I also installed new coils. It runs about 95% normal now. No codes other than a battery monitoring code. Last year when we decided to get it out of storage, I took it to a BMW mechanic (not a dealer, just a guy who specializes in German cars) and he couldn't figure out what was going on. He replaced the wiring harness, and I'm betting he forgot to hook up the battery monitor when he did it.

It is still running a little wonky, but I think that has to do with the fact that it has 3 year old gas in it still. I tried pumping it out, but my tube for my pump isn't long enough. I put stabilizer gas treatment in it and I'm just going to run it out. I burned 1/4 tank just zipping around the neighborhood just now.

I'm pretty sure it's mostly fixed, as I got up to 6500 RPM with no problem, and it pulled pretty hard the whole way. Now I need to take it up and get it smog checked so I can put a new plate sticker on it so my son can drive it. I'll post again if I find anything else worth reporting.
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      10-02-2024, 07:50 PM   #10
c131frdave
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Quote:
Originally Posted by tobiasgt View Post
Hi, I have the same Problem. Cold start is fine. After warm up misfires. Did u fixed ur car?
I would suggest pulling your plugs and looking at them for leaky injectors. If it's a bad leak, it will be wet. If it's a small leak, there will be lots of black crap on them. If they all look good, replace your ignition coils. If they look burned up, replace both the coils and the plugs.
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