Hi, welcome back to jA....few questions...
~Rip
oops... my typo. Yes, it is a 630Ci.
The only thing remaining is the EGR valve, but none of the plumbing leading to the valve is left. The three electric valves (blue, red and white) are all gone, as is the piping from the exhaust manifold. The Air Pump is gone, and all the plumbing that goes along with it. I think the reactors are also gone, but it's tough to see what is missing when you don't know what was there in the first place.
There is a port at the back end of the rear manifold. It was plugged, but exhaust was leaking from there. I fashioned a plug from some brass fittings that I had in the house. There also seems to be a leak at the exhaust manifold/exhaust pipe interface. I changed the exhaust system from the manifold back some time ago. It was difficult to get leverage to tighten this interface, and I feel it needs to be tightened some more. Is it too dangerous to use an air impact wrench to tighten these bolts? I don't want to risk snapping off the stud.
I would tighten any exhaust bolts/nuts by hand...if they are rusted/corroded spray them down in WD-40 and let it sit overnight. They may break regardless...often they need to be changed out. Any exhaust leaks will not affect the engine performance. Too answer your first question, removing the emmisions components themselves doesn't affect performance, but if the ports are not plugged off properly at the engine intake, this can cause a problem (vacuum leak). Your second question refering to the procedure used to remove the components, is bascially they were jsut bolted off and everything plugged. If the EGR is still in place, it has to be plugged off properly, other wise manifold vacuum can leak from there. Try spraying carb cleaner around the areas where parts were removed on the intake, while the engine is running. Try to keep from spraying at Ignition parts, to keep from starting a fire. If the engine idle changes when you spray a certain area, this entail a vacuum leak exists there. I'd pay close attention to the EGR valve and ports, but also check the rest of the intake manifold and vacuum hoses. In any cases, this sounds like a vacuum leak concern, wether it be related to the removal of the parts, or not...if no vaccum leaks are found I would check the compression of the engine, and the valves for adjustment.
We're almost there. Do you know the procedure of how the reactors were disconnected and the communications with the exhaust system were plugged? This is very important to the exhaust leak part of my question.
Also, the nuts securing the pipe to the manifold are copper. Should I still refrain from using the air wrench on these? It is nearly impossible to get any kind of leverage under the car. If I were on a lift it would be different, I think... but I"m not.
You can try an air impact, but be carefull, give it small spurts and still use WD-40..you can get new copper lock nuts inexpensively...they're better new. Can you explain what you describe as reactors?
See #1 in the diagram below:
Those are part of the exhaust manifold...so if they're missing (unless fabricated, removed and welded) I would assume they used a manifold from a grey market model...I just don't see why anyone would go through the trouble of removing them completely...
Therein lies the problem. The reactors are gone and it feels (since I cannot actually visualize the sides of the manifold) like there are stubs there. I wanted to know how folks have removed these in the past, using the existing manifolds (which it seems that they have done)
I see, than they must have just cut them off with a torch...and welded the holes shut. Are there exhaust leaks there?
Well...there regardless of wethere they are on there or not, it will not affect the engine performance, the worst would be an exhaust leak thay may not be repairable without removing the manifold and welding it with trial and error. Now can you elaborate on " and the communications with the exhaust system were plugged?"
It won't affect performance of the engine, unless the EGR- to- the intake port leaks...so if the exhaust side isn't plugged well..than under load when the EGR is supposed to be open, it would suck in air, causing a performance issue...but if the vacuum supply to the EGR has also been disconnected/removed...than it can't affect anything. Other than that, the Air Injection system cannot affect performance in anyway, for emmisions reasons the air is injected to the exhaust to provide more oxygen for the catalyst to react to Nox (Nitrous Oxides)...other than that, it has no use.
I'd like to focus on the exhaust issue. The vacuum leak issue will hopefully be solved when I change all the gaskets on the air tubes and I change the vacuum limiter. All the other hoses are new. I also have to check the vacuum connection to the charcoal filter. That may be another source of vacuum leak. I know the EGR is not leaking, I've checked that already.
The exhaust leak is where I need to focus, because it is annoying to constantly smell the exhaust in the interior. It's the exhaust manifold, particularly the removal of the emissions controls. It is there that I need the help.
Than the best solution would be to locate the leaking areas by having an assistant plug the exhaust at the tailpipe with a thick balled up towel, while the engine is running. Never hold the towel against the tailpipe longer than 10 seconds at a time. The pressure will cause the leak to become worse up front, than you can pinpoint each area, I would mark them with tire chaulk or equivalent. Than the manifold can be removed and taken to a shop where it can be welded over.
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BMW Factory Training, ASE Master Techinician, Advanced engine performance.