Where does this hose go?

[goody90q45]

I've been getting the EGR code lately so I took it out today to give it and the tube a good cleaning. With it removed I noticed this blanked off hose (vacuum tubing?) sticking out from underneath the plenum and capped off with a bolt.

I haven't gotten to experience the joy of removing the plenum yet so I don't know where it comes from or where it's going to. Does anyone recognize it and know where it should be connected to? Would this being capped off have anything to do with the EGR code I'm getting? Thanks in advance for all your help.

[elwesso]

Does your car have TCS?

[goody90q45]

Does your car have TCS?

No. She's a standard Q.

[elwesso]

It looks to me like it just loops around back in front of the black throttle things.

herse a diagram.

[goody90q45]

Thanks Wes. I'll check it out in the A.M.

[CrimsonQ]

same hose on my non tcs Q

[goody90q45]

same hose on my non tcs Q

I don't understand. It sounds like you are saying you've got the same blanked off hose on your Q? Is this a non-issue. Thanks.

[CrimsonQ]

edit:

i was looking at the other hose, not the clearly marked red arrow hose. sorry

[Jesda]

I had a few of those capped hoses on my Mazda MPV and 929s. Weirdest thing...

[redmanfx]

It's in allot of pics in the FSM and it's connected back into other hoses in every picture.

[goody90q45]

Upon further investigation, I've determined that the capped off hose shown in my picture is the hose from the EGR solenoid valve shown in the drawing below. It's the hose from the single-hosed end not the double-hosed end.

I had the throttle body off last week for cleaning and it had 4 hoses that fed into it- 2 on the left and two on the right, one of each size. With these four attached on reassembly I could not find a place for this capped off hose to attach. Having this hose disconnected and capped from the EGR solenoid would explain why the code gets thrown.

I've studied the schematic from the emissions section of the FSM but it's not to scale and doesn't really show the exact connection point under the plenum.

Does anyone know where this hose should connect at the plenum?

[Raxephon]

Maybe this will help.

[PopPop]

Upon further investigation, I've determined that the capped off hose shown in my picture is the hose from the EGR solenoid valve shown in the drawing below. It's the hose from the single-hosed end not the double-hosed end.

I had the throttle body off last week for cleaning and it had 4 hoses that fed into it- 2 on the left and two on the right, one of each size. With these four attached on reassembly I could not find a place for this capped off hose to attach. Having this hose disconnected and capped from the EGR solenoid would explain why the code gets thrown.

I've studied the schematic from the emissions section of the FSM but it's not to scale and doesn't really show the exact connection point under the plenum.

Does anyone know where this hose should connect at the plenum?

Mike this line runs to your EGRC=Solenoid Valve. On standard models it is around #5 & #7 area of cover and the hose is part number 22320HA and connects to the EGRC=Solenoid Valve number 14956V and then a single hose runs from there and splits into a Y and one goes to the EGR Valve and the the other runs to the EGRC BPT Valve!

[goody90q45]

Upon further investigation, I've determined that the capped off hose shown in my picture is the hose from the EGR solenoid valve shown in the drawing below. It's the hose from the single-hosed end not the double-hosed end.

I appreciate all your inputs but I am still having a hard time figuring out where this capped off hose should connect.

Wes- The hose you circled is already connected. It comes in from one of the metal tubes under the plenum and loops back around to the plenum throat behind the throttle body.

Anlasak- Thanks for the drawing but it just gave me a headache and made me dizzy. (LOL) I can't decipher it.

Redman- Hopefully the picture below will clear up any confusion I may have created.

Tyrone (PopPop)- The path you're describing is from the first looped hose on the right side of the EGR solenoid valve. The one I'm questionind is the single hose on the left side of the solenoid.

I've marked up the picture of the EGRC solenoid valve to better describe the problem. Here's what the pic is trying to show:

- The hose with the plugged end that I showed in the first picture in this thread leads back to the single hose side of the EGRC solenoid valve.

- The hose Tyrone described is the first looped hose on the other end of the EGRC solenoid valve. It goes to the EGR valve and EGRC-BPT valve and comes out from under the plenum betweeen FI #5 and #7.

My dilemma, and what I think is the reason for the ECU code, is that the solenoid is not getting any vacuum (?) signal since the hose is capped off.

In the end, I think I'm going to end up removing the throttle body (again) and unbolting the plenum (again) so I can lift it up a few inches and write down what all the hoses are connected to.

Any additional suggestions would be appreciated. Thanks.


Modified by goody94q45 at 5:32 AM 10/11/2008

[PopPop]

I've always done 90% of my work on 90-93 Q's and the EGR Sol. are located by where the hose that is plugged around #5&#7. Where yours are located over top of the cam positioning sensor are found on models with TCS in 90-93 and maybe 94 not sure about 94 like I said I know 90-93 very well. If 94 with TCS have the same system as the 90-93 vacuum wise then I would say that your car either had TCS or someone installed a TCS motor in your Q but left the EGR system the same and that is why your hose is blocked off. On standard Q's you have one solenoid over #1&#3 cylinder area and the second over the #5&#7 area with the plumming running along the left bank valve cover area. You have only 2 hoses that come from the right side of the throttlebody one is a coolant hose and the other is the vacuum line that runs to your EGR System. The Models with TCS vacuum system runs like the one in your illustration with the plumming running under the plenum and coming out around the areas of the TB and both solenoids are at the front as in the pic's. My Engine was an TCS version but I have one at the front where yours EGR Solenoid is and the other is at #5#7 are where your is plugged and then it goes from a single to a Y split.

[3Q Jay]

of course i can never find exactly the picture i'm looking for.....

this is from my plenum job in aug 2005. i believe your hose that is capped is this one?

[IMG][/IMG][IMG][/IMG]here's a different diagram.



again--the circled hose maybe?

of course i don't remember any more, but i'm thinking that the open end hose in my picture goes to the TB for ported EGR vac?

Tyrone- you are right, the 94 does have both solenoids up by the CAS--not like the 90-93 std.

[goody90q45]

Thanks Jay. That drawing looks like my 94 engine with both solenoids in the front of the engine. The other was for a 90-93. I'm still not sure where that hose goes so it looks like tomorrow I'm going to remove the throttle body and EGR and write down where all the hoses from the solenoids (EGR AND cannister) terminate. The EGR solenoid certainly needs a vacuum signal and its not getting it with a plugged off hose.

Another NICO member, Nistech (Scott) from Elk Grove, contacted me and we are going to get together for him to look at it. Scott's a tech at the local Nissan dealer and says he can figure it out in 5 minutes or less.

[goody90q45]

PROBLEM SOLVED!! I've been reading and troubleshooting this problem for about a year now and finally figured it out today.

I pulled off the throttle body this morning in order to trace the path of and pressure check all the vacuum lines in the EGR system. When I got to the line that sends the vacuum signal to the EGR solenoid (the one circled by Wes in the pic posted below and the same as the curved metal tubing below the plenum opening in Jay's pic posted above) I found that it would not hold a vacuum.

I followed this line under the plenum with an inspection mirror and found a piece of rubber tubing missing and in its place a long piece of capped off tubing inserted in its place (see the first pic in this thread), but not plugged into its spot in the rear of the throttle body.

As far as I can tell this "pirated" piece of tubing was put there to be plugged in before a smog check (every 2 years in CA) and then unplugged and capped off after the test rendering the EGR system inoperative. I'm glad I finally found the problem. I was getting tired of having the CEL come on (and stay on) every time I drove more than 20 minutes.

Thanks to everyone for your input. Y'all kept me going back to read and troubleshoot rather than breaking down and taking it to a shop. Special thanks to Scott (Nistech, moderator from the Nissan Online Mechanic board) who was going to meet up with me today to try and figure out the problem. Scott, I'll save your services for another time. I'm lucky to have you so close.

NICO comes through again and saves me some big bucks. Time to send another donation to the Hitman.

[3Q Jay]

awesome Mike--good to hear persistence paid off. people will do the darnedest things....good plug for NISTECH, too. He's helped answer several questions in the past for my daughter's alty.

[texasoil]

From the weirdness of the 'gordian knot' of hoses and pipes on top of the Q45 engine, I'd bet the guys that designed the 'system' never looked at the engine.I could be vastly simplified. There are multiple connections for manifold vacuum, multiple water temp sensors, etc.

[OwnerCS]

From the weirdness of the 'gordian knot' of hoses and pipes on top of the Q45 engine, I'd bet the guys that designed the 'system' never looked at the engine.I could be vastly simplified. There are multiple connections for manifold vacuum, multiple water temp sensors, etc.

When I first removed the plenum and looked at the hoses I thought -- this reminds me of the NYC subway system south of Canal Street. What bunch of layers of tubes -- HA!

Could this be an early automotive application of quantum vacuum engineering for propelling our space screws beyond the next planet?

I like Texasoil's gordian knot assessment the best.

I think I will be grouping the lines into some grouping of sub-assembly units when reinstalling the layers. I took dozens of picture during the removal process to guide me through the reassembly process.

Do we need a "Project Alexander" to cut the knot?

Is there any value in some type of vacuum tube organization manifold like the picture below?