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Discussion Starter #1
Good evening,
I just recently replaced the valve stem seals on a 2007 BMW 750i with a 4.8L N62B48B engine. I went to start it up and the engine runs rough then stalls. This problem never existed prior to the job. I did disconnect the and remove the intake manifold during the process, upon replacing it I installed new intake seals. I did switch around the camshaft sensors and no changes. I ran a smoke machine and there are no leaks. The coil packs seem to be working because when I remove the connector the engine gets worse.
The codes I am getting, Engine Codes, on my Snap On reader in which the software was just updated on it, are as follows:

2A13 - DMTL - leakage diagnostic pump
2B62 - camshaft sensor, intake
29CC - combustion misfire on several cylinders
29CD - misfire, cylinder 1
29D0 - misfire, cylinder 4
29CF - misfire, cylinder 3
29CE - misfire, cylinder 2

Please note there are NO vanos codes.
In reassembling the car I do have the air filter intake tubes connected "half a**" just so i can start the car with the MAF connected. I also am wondering what the vacuum line going to the MAF sensor area is for. I did replace the vacuum lines with new ones. they were getting a little dry aging dust I and though since I am in there why not just do it?
Thanks
 

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CRISP & CLEAN
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4,144 Posts
Good evening,
I just recently replaced the valve stem seals on a 2007 BMW 750i with a 4.8L N62B48B engine. I went to start it up and the engine runs rough then stalls. This problem never existed prior to the job. I did disconnect the and remove the intake manifold during the process, upon replacing it I installed new intake seals. I did switch around the camshaft sensors and no changes. I ran a smoke machine and there are no leaks. The coil packs seem to be working because when I remove the connector the engine gets worse.
The codes I am getting, Engine Codes, on my Snap On reader in which the software was just updated on it, are as follows:

2A13 - DMTL - leakage diagnostic pump
2B62 - camshaft sensor, intake
29CC - combustion misfire on several cylinders
29CD - misfire, cylinder 1
29D0 - misfire, cylinder 4
29CF - misfire, cylinder 3
29CE - misfire, cylinder 2

Please note there are NO vanos codes.
In reassembling the car I do have the air filter intake tubes connected "half a**" just so i can start the car with the MAF connected. I also am wondering what the vacuum line going to the MAF sensor area is for. I did replace the vacuum lines with new ones. they were getting a little dry aging dust I and though since I am in there why not just do it?
Thanks
Check the fuel injectors , there is a small ( Green or Grey ) rubber O-ring that probably
came off one of them when you removed the fuel rails . Had this problem
a few years ago when the same job was done .
 

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Discussion Starter #3
Good evening,
I just recently replaced the valve stem seals on a 2007 BMW 750i with a 4.8L N62B48B engine. I went to start it up and the engine runs rough then stalls. This problem never existed prior to the job. I did disconnect the and remove the intake manifold during the process, upon replacing it I installed new intake seals. I did switch around the camshaft sensors and no changes. I ran a smoke machine and there are no leaks. The coil packs seem to be working because when I remove the connector the engine gets worse.
The codes I am getting, Engine Codes, on my Snap On reader in which the software was just updated on it, are as follows:

2A13 - DMTL - leakage diagnostic pump
2B62 - camshaft sensor, intake
29CC - combustion misfire on several cylinders
29CD - misfire, cylinder 1
29D0 - misfire, cylinder 4
29CF - misfire, cylinder 3
29CE - misfire, cylinder 2

Please note there are NO vanos codes.
In reassembling the car I do have the air filter intake tubes connected "half a**" just so i can start the car with the MAF connected. I also am wondering what the vacuum line going to the MAF sensor area is for. I did replace the vacuum lines with new ones. they were getting a little dry aging dust I and though since I am in there why not just do it?
Thanks
Check the fuel injectors , there is a small ( Green or Grey ) rubber O-ring that probably
came off one of them when you removed the fuel rails . Had this problem
a few years ago when the same job was done .


The fuel rail was never removed. When I start the engine the exhaust smells rich.
 

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Sick Puppy Motorwerks
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It almost sounds like you forgot to plug something in (maybe not fully plugged in?)
Do you have any connectors just lying there on the passenger side of the engine?
 

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I have replaced the Camshaft sensors with new ones and I still have the same exact codes.
in all honesty when ever u have a whole bank bad its your o2 sensor on that bank exhaust

Sent from my SM-N950U using Tapatalk
 

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Sick Puppy Motorwerks
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in all honesty when ever u have a whole bank bad its your o2 sensor on that bank exhaust

Sent from my SM-N950U using Tapatalk
There is also an exhaust gas temp sensor in the downpipe, along with a pre- and post cat O2 sensor. This sounds more like something is not fully plugged in, especially since the motor ran fine prior to the work.
 

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There is also an exhaust gas temp sensor in the downpipe, along with a pre- and post cat O2 sensor. This sounds more like something is not fully plugged in, especially since the motor ran fine prior to the work.
never heard of a exhaust gas temp sensor controlling a whole bank ..pre cat O2 sensors do

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Discussion Starter #9
If an O2 sensor was malfunctioning, or any sensor in the area, wouldn***8217;t it throw a trouble code?
 

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Check then IVM I had exactly the same misfires checked by a mechanic... told me change the cam sensors luckily before I decided to change them I came across another forum post about the IVM which according to the post it controls cam, fuel injectors along with a few other things I can’t completely recall , I personally had a no start/crank issue also a hard start issue which was intermittent, I found the part at a dealer (I called a few different local ones; prices vary) for about 137 and some change fixed it’s all for me. Also when I pulled out the old IVM I took apart the top very gently and carefully with a screw driver and the a solder point was cracked and the chip looked sort of dirty. Took about 20 minutes to do it’s under the passenger side cabin filter


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Discussion Starter #11
The IVM is good. New battery installed and the alternator is good. Same problem still exists.
 

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Discussion Starter #12
Just a thought, if I remember correctly, back tracking, and brainstorming, I kind locked the cams when performing the seal replacement. When I applied shop air to a cylinder there was rotation then stopped due to a vise grips, or whatever I had, there. Is it possible that the vanos cams ***8220;slipped***8221; or moved, or the vanos cam maybe ***8220;locked***8221; hence the engine maybe starving for air or the timing maybe off? The engine starts no problem everytime it just runs terrible.
 

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Check that the two front vanos solenoids are seated properly. Push all the way in. Compare the right and left side if you are not sure.
 

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Discussion Starter #15
I finally got a minute on my busy schedule to tinker with this car. I decided to do a compression test first. Cylinders, left side/ driver***8217;s side, 5-6-7-8 are good. Passenger/right side, cylinders 1-2-3-4 have no compression. I am going back to my previous thought that something ***8220;slipped***8221; when I applied shop air while doing the valve seals with the AGA tool, obviously the timing is off and or bent valves......I could be wrong. I did turn the engine by hand 4 times before replacing the valve covers and there was no issue.
Any thoughts?!?
 

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Discussion Starter #17
Good day everyone. I wanted to close this thread and add information for others out there who have or are attempting to work on the N62 4.8 engine.

Going back to a previous post of mine I had the suspicion that the intake cam slipped while I was adding air to a cylinder. It turns out that the intake cam was off a few degrees. Now being that this is an interference engine the probability of the engine having bent valves is very high. However before I started the engine I manually crank the crankshaft by hand to make sure there was no interference. It turns out that, I guess some would say I got lucky, and a few degrees is/was OK. I obtained a timing tool and correctly timed the engine. The intake cam on cylinders one through four was off, I corrected it, did a compression test, and all my compression came back. I reassembled the engine and it started like a charm. Presently she runs like a top, and I have no complaints. The engine has plenty of power and no smoke.
 
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