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no backpressure on bpt valve
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ionmachiman
User
Jul 6, 2009, 5:41 AM
Post #1 of 8
(6669 views)
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no backpressure on bpt valve
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Hi
car:nissan altima 93, 208000km, 2.4 l, automatic (the guy with the air conditioning  )
the egr system doesn't work
now, if i blow a little in the backpressure hose of the bpt valve then the system works
(as i increase the rpm the egr valve moves)
from the engine nothing comes out for that hose (as i understood backpressure reference from the exaust)
probably it is clogged somewhere; this hose, that connects the bottom of the bpt valve, goes to a pipe that is comming out from a piece with a rusty appearence, placed on the engine, and having 2 other pipes, one larger;
now how can i unclog my pipe? i put in some stuff for rusty bolts-nuts, and tried to blow it in with a pump, just to push the liquid a little;
is there a valve or something?
how can i unclog it?
ty
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ionmachiman
User
Jul 6, 2009, 7:24 AM
Post #2 of 8
(6663 views)
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Re: no backpressure on bpt valve
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apparently it worked and it's unclogged; now the egr system works;
i'l have to check it more often;
last time i unclogged, 2 years ago, 1 month after i passed the aircare;
i did have very high nox (???) but passed 5% under max limit; befor the aircare i changed everything: oxigen sensor, catalitic convertor, air filter gas filter, distributor cap and rotor, cylinder pressure was very good; but i didn't check the egr.
i thought that the way my car was handled brought such an result; can you pass with egr not working???
what is the piece that provides the backpressure for bpt valve and have that pinhole, so i can change it and forget about it for a while?
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ionmachiman
User
Jul 6, 2009, 9:32 AM
Post #3 of 8
(6657 views)
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Re: no backpressure on bpt valve
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i checked it again, and now doesn't work, no pressure for backpressure port;
probably there is something that clogs the pipe (actually there are only 2 pipes in the thing, not 3 as i thought before)
is it hard to take that piece out? looks like i need 2 flarenut wrenches; the small one i have it but for the large pipe
i don't have it and i can try use a regular wrench; that thing is rusty and probably the threads are clogged with rust
should i try it? are there behind some hidden springs, or pop-up things?
ty
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ionmachiman
User
Jul 6, 2009, 9:51 AM
Post #4 of 8
(6656 views)
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Re: no backpressure on bpt valve
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i found a picture on internet
the thing is called egr passage
i attach the picture; in it, the pipe out, to plug the hose going to bpt, is cut, but you can easily see the place
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ionmachiman
User
Jul 6, 2009, 10:15 AM
Post #5 of 8
(6654 views)
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Re: no backpressure on bpt valve
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i found from other postings that the casting of egr passage breaks very easily; also the big pipe breaks easily (???)
because of the rust build up ;
how can i open the nuts without breaking anything?
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ionmachiman
User
Jul 6, 2009, 12:21 PM
Post #6 of 8
(6650 views)
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Re: no backpressure on bpt valve
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i checked again, it worked; now i checked the backpressure and it was about 1 psi;
i put in some more cleaners (wrench cleaner and carb cleaner); then try it again didn't work ;
now with backpressure 1 psi didn't work;???if i blow the backpressure hose the egr system works;
???
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Sidom
Veteran
/ Moderator
Jul 6, 2009, 3:47 PM
Post #7 of 8
(6642 views)
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Re: no backpressure on bpt valve
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I'm a little confused here so I just add a little bit ...
Those nuts are easy to break.... The best thing you can do is to soak them down with PB blaster penatrating oil. The stuff works wonders. I'm not sure how you are check your EGR valve but the car needs to be running & then apply vacuum to the egr valve & the engine should run rough or even die.
If the egr system isn't working this could cause to much nox. The egr system is used to cool the combustion camber, an over heating combustion chamber produces higher levels of nox....
HTH
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ionmachiman
User
Jul 7, 2009, 2:47 AM
Post #8 of 8
(6630 views)
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Re: no backpressure on bpt valve
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can you please tell me, how much should be the pressure in the backpressure port of the bpt valve?
(nissan altima 93 2.4l)
lets say that the casting breaks together with the pipes;
if i have to wait for parts better order them all;
there is the large pipe, the small one, and the egr passage-casting;
is that all?
maybe there is a hole in the engine and a connection with the casting, and i'll need something more?
ty
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