Results 1 to 13 of 13

Thread: Secondary Air Bypass

  1. #1
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport

    Secondary Air Bypass

    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?

  2. #2
    Join Date
    May 2017
    Location
    USA
    Posts
    159
    My Cars
    E90, E46
    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...

  3. #3
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    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.

  4. #4
    Join Date
    May 2017
    Location
    USA
    Posts
    159
    My Cars
    E90, E46
    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

  5. #5
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    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.

    - - - Updated - - -

    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.

  6. #6
    Join Date
    May 2017
    Location
    USA
    Posts
    159
    My Cars
    E90, E46
    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.

  7. #7
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    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.

  8. #8
    Join Date
    May 2017
    Location
    USA
    Posts
    159
    My Cars
    E90, E46
    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

  9. #9
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    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.

  10. #10
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    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..

  11. #11
    Join Date
    Dec 2016
    Location
    Texas
    Posts
    21
    My Cars
    2004 545i Sport
    Does anyone happen to know the hole/port diameter at each cylinder location? The ones that are reported to clog?

  12. #12
    Join Date
    Jan 2007
    Location
    .
    Posts
    7,708
    My Cars
    .
    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

  13. #13
    Join Date
    Jan 2016
    Location
    Ca
    Posts
    6,981
    My Cars
    2001 525it
    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.

Similar Threads

  1. Easy way to bypass Secondary air pump?
    By H2oiamwater in forum 1991 - 1999 (E36)
    Replies: 11
    Last Post: 05-15-2010, 01:37 PM
  2. secondary air flow system
    By cms in forum 1991 - 1999 (E36)
    Replies: 2
    Last Post: 03-06-2003, 01:50 AM
  3. PARTS help: I need a Secondary Air Pump and Check valve
    By J10B in forum General BMW and Automotive Discussion sponsored by Intercity Lines
    Replies: 0
    Last Post: 01-06-2003, 10:33 AM
  4. Secondary Air Injection Bank 1 Flow Too Low
    By Boston318ti in forum General BMW Mechanical Help sponsored by RM European Auto Parts
    Replies: 7
    Last Post: 08-21-2002, 04:20 PM
  5. Secondary Air Pump Replacement 328i
    By Ciaran Hanrahan in forum General BMW Mechanical Help sponsored by RM European Auto Parts
    Replies: 3
    Last Post: 04-15-2002, 06:34 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •