I moved the vehicle to plow out the drive way when this message appeared on the dash:
I thought I was back in Iraq and an IED went off. I heard a loud My boom and my hood popped open. This is what is the carnage:
What would cause the the intake to backfire creating this catastrophic damage? There were no warning signs. I just drove the car to and from work (70 mile round trip) last night with no issues. I moved it to plow the driveway then this happened when I pulled it back in. The CCV was replaced last summer.
Does anyone have an E46 2.5i intake they could part with?
EDIT: Upon further inspection, It appears the DISA valve flap was broken.
Me too. There were no warning signs, just a huge backfire then BOOM! I just found another intake manifold, I’m going to replace everything that can fail in the intake system, to include all the injector o-rings. The only thing I can think that could cause it may be a leaking fuel injector. I’ve found a few issues of this happening, but no definitive answer to the root cause.
I’m not sure yet, at least until I get it pulled apart. I can see that the plastic around the flap is broken off. Just waiting for some warmer temps to pull it apart, as my garage is full of old furniture and construction waste.
oh ok gotcha… yea that pin can do alot of damage to the valves… ive also seen bad maf cause it to back fire into the intake before never seen a manifold explode tho
You know this would be a excellent moment for me to say yet again that you and bmws just do not mix well, but unfortunately this is not that uncommon on this car. Theres quite a bit that can cause intake backfires and i cant just list them all here, only some serious diag may pull something up clear cut especially if the car was running fine only moments prior to this.
I will recommend that you do have the injevtors tested, and have a leakdown test performed on the motor. Two common issues for manifold backfires are puddled fuel and burnt valves. While the first would be difficult in this setup with the manifold design its not out of the question. If the fuel preignighted before the valve closed or th valve was not fuly seated youd end up exactly where you are now in most cases. Definitely look at the backside of the intake valves, you may see some telltale signs.
Be certain te ports are clear before running comp or ld tests on the motor.
The DISA actuator probably broke when the thing went poof, but that system is failure prone anyway and its recommended to rplace or retrofit the actuator every 70-80k or so. Those actuators are bout 2-250 online but there were kits to “beef them up” a bit so to say.
Thanks Adam! I just got it apart and the entire CCV system was frozen solid. Do you think this could have pressurized the system causing the failure? It’s my wife’s car and she drives it on numerous short trips. I asked her, and she doesn’t let it warm up to operating temperature, even after a short trip in the cold. Here’s a couple of pics of the CCV. I just replaced this this summer. The vehicle just hit 100k miles, we’ve had it for 6 years.
Geez man, I’ll bet the oil is a mess too. They do sell titanium/aluminun DISA valve pin Kits, but I gather the DISA just plain exploded.
On a side note, I’m glad you checked the P/N on that manifold because I swore it was from a 330. Upon further review of my memory, I realized the replacement motor that went into the car I got the manifold from had the complete intake manifold with DISA for the 330 motor. The only part that I had to swap was that vacuum equalizer bit because it cracked up during shipping and not the entire manifold… thus causing me to think the manifold was a 330! It is an M54 mani though, so you’re golden!
Keep posting pics of the carnage, I’m really interested to see what else was going on to cause this type of failure!
It’s possible there was a lot of carbon build up on the valves causing a piss poor seal and that in combination with a leaking injector/clogged ccv popped the manifold. I wouldn’t say the engine is junk, but it was certainly put through some shit. At the very least a seafoam treatment is in order. If you get a chance, look into the intake ports to check the top of the valves.
A clogged ccv wont cuse that kind of explosion directly, but may lead to to th issue yes. I still dont think thats the root cause. If the ccv plugs you can low seals and ive heard potentially pop the valve cover, but not the manifold.
Disa failure wouldnt cause it either. When they fail completely the motor usually eats the disa actuator parts and is dead.
Carbon buildup is a likely contributor. As i mention before and was stated by others, if a valve hung open on a firing cycle…borrow or renta leakdown tester if you dont have one. Thats a test i would certainly do before anything else.
Heyt least your getting proficeint at working on these cars now!
I really appreciate your help , Adam! I’m going to wait for a warm day to go through it, my garage is full of old furniture and construction waste from my house. I just got the other intake manifold swapped onto it. I replaced anything and everything intake related. So far, it seems to run smoother, but it never had an SES light before. I can notice a considerable difference in the vehicle. My wife wants a new/newer vehicle anyhow. We’ve had it for 6 years. We may just trade it on a CPO Porsche Cayenne/BMW X5, as my wife likes (wants) both of those vehicles.
