I was thinking today about the problematic nature of the secondary air ports within the heads clogging on the N62 engine. I am convinced someone NEEDS to make a conversion kit that will replace the metal tube between the valve and the head, and plug the head. The new tube coming off the valve would be a simple flexible metal line say 1/2" in size that goes down and taps directly into the exhaust manifold like most cars.... done. You could simply tap into the original tube and attach the new flex line... possibly block the unused portion going to the head.
No? I think a kit like this would accomplish the same goal while completely eliminating the original design flaw.
What cha think?
It's not a bad idea but the biggest issue I see would be tapping into the exhaust cleanly. Ever try to weld a bung onto an exhaust? The metal is very thin and it's quite easy to blow holes in it instead of weld.
Also I don't see a need to block the head, instead just cap the metal tube and this will essentially do the same thing.
thats my thoughts atleast...
Right... I would use the original tube to still go inside the head, but block off the inside of the tube somehow, then tap into the tube about half way back to the valve for the new line. Im not sure how thin the manifold metal is, but I can always turn the power down fairly low on the welder. Any idea if the manifold tap location or distance from the cat will make any difference? In other words... would it be best to have it as close to the head as possible, or will it not matter? I would hate to have to drop the manifold in order to accomplish this task.
All the secondary air does is inject fresh air during the warm up phase which is detected by the O2 sensors.
as long as your upstream of the O2 sensors I don't foresee a problem but this is not a common practice so it's a guess.
I'm guessing you have secondary air issues? Clogged heads are not that common honestly...it's kind of a mass hysteria thing where a few people have had it and now it causes fear in everyone...
Most common is pumps dead or working but not blowing hard enough, secondary air valves sticking closed, programming issues with DME sensitivity, cheap plastic tubing under the intake breaking, electrical issues involving the pump circuit, vacuum issues. Before you go all banana sandwich I'd make sure that a clogged head is really your issue as again fairly uncommon. After 10,000 N62 engines I've seen dating back to like 05 I think I've seen maybe 1 or 2
Interesting!
Yes, I have had the "insufficient flow" codes for a few months now. I have verified the pump functions, but I haven't replaced the valves or pulled the intake to look at the tubing.... unless there is a better trick to test for leaks without pulling the intake? Also is there a way to check the valves?.. I dont think they are vacuum operated for some reason.
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Could you theoretically disconnect the hose up by the radiator and force air into it to verify the valves open? I would imagine it hard to know even then if they open.
I can't remember 100% but I don't think the N62 secondary valves have vacuum nipples.
try this in this order:
verify pump works
pull hose off and see how hard its blowing. It could just be making noise. It should have a pretty impressive force to it.
check the lines from the pump to the valves which requires intake removal
if you R&R the intake there is no reason not to replace the valves at that time.
if I had to guess I'd say you have a hose break or a stuck valve, again- Internet guess
if you had access to a scan tool that does activations you could activate the pump and put your hand over the exhaust and feel for air coming out the tail pipe
Last edited by SlackTube; 07-27-2017 at 08:11 PM.
Im a fairly good do-it-yourselfer, but I havent graduated to a good scan tool other then the worthless obd. I also have valve seals needing to be done which I plan on tackling myself. I know assumptions are not a good idea with these cars, but I figured the secondary ports to be clogged given the fubared valve seals.
Valve seals is a big job for the do-it-yourselfer but good luck!
valve seals are far more common then clogged secondary air passages
Meh... nothin to it. Think I've seen worse.
Any way to test the valves? This car only has 80k on the odometer and isn't exactly cooperating.
Ok, so I disconnected the pump hose at the connection by the vacuum pump on the PS head. I then started the car on a cold motor and the pump blows like crazy out of the disconnected hose. It is possible however to block off the air pressure with my hand, but again I am unsure just how much force its supposed to have. I then shut off the car and connected a 3/4" hose to the Y connector hose that leads to the valves and blew into the hose. From what I can tell, atleast one valve is def opening as air went through and it sounded like a diaphragm and not a leaking hose. I really think my hoses are fine..
Does anyone happen to know the hole/port diameter at each cylinder location? The ones that are reported to clog?
Sounds like it's time to bite the bullet. Remove the heads, remove the valves, drill out the passages (the carbon is hard as a rock, you'll need a drill bit), renew all the valve stem seals, and reassemble the engine.
I've done plenty.
ASE and BMW Master Certified Technician
Ther was somebody who modified the secondary air system in the e39 m5. What made his mod possible is because the pre cat oxygen sensors were in the down pllpes to he ran air pipes in to the down pipes, installed the valve to the air pump.. if the pre cat oxygen sensors were in the exhaust manifold right out side the heads then the mod would be a lot harder. The pre cat oxygen sensors are the measuring secondary air so since the passage ways are clogged the mixture coming out of the cold start engine is rich, the air pump leans it out when it is working correctly.
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