Vacuum Lines

sparkyjohnmarky

Forum User
Hi All,

I have registered with the forum, after purchasing a 1987 300zx. I received the vehicle last week and on closer inspection the vehicle has been really pulled apart. The fuel & vacuum lines have been discarded, the cruise control disconnected and the airbox is also missing. I bought the car as a project, with the hope of completing the restoration within a year. I have consulted the service manual I have, but it is for a US model, which is very different from mine. The US model has a number of emission control parts which are not present in my vehicle, so the vacuum layout is somewhat different. Can anyone advise me how to re-instate the vacuum control with a diagram. Also The vacuum tank near the header tank only has 2 nipples on it and it appears to need 4, does this item require replacing? Any help you could give me would be gratefully appreciated.

Many Thanks
 

sparkyjohnmarky

Forum User
Hi,

Thank you for your reply. I have the the service manual from this website, it is very insightful, but its for the U.S. model which has all the emission control features. Because the previous owner of this vehicle has removed so much under the bonnet I am unsure of what should be present. In the vehicles current state the following, are missing but listed in the above manual. I therefore do not know whether they should be present.

Carbon canister
Air induction Valve + solenoid
Egr + Solenoid

I wondered if there were some z31 owners on the forum, that could confirm whether these items should be attached to my vehicle, which is a normally aspirated 3.0l auto transmission.
 

sparkyjohnmarky

Forum User
Hi all,

I have attached the photos of the Vacuum lines. I have annotated the line where the connection is unknown to me as "unknown". I would appreciate it if anyone on here with a z31 could clarify these connections for me.

Regards
 

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Mr.F

Inactive
Picture 1 - on a UK car the two lines marked unknown are left open at each end of the four line rail.
UK cars don't have a carbon cannister.
The others - I'd have to look at another car to remind myself!
 

sparkyjohnmarky

Forum User
Thanks Mr F, That is a great help. Your answer completes the 2 unknowns in picture 2 as well, these are the other ends of the 2 lines you say are left open in pic 1. Its just the last one in pic 3 next to the auto trans vacuum.

Thanks again
 

Mr.F

Inactive
Do you have a servo pipe connected to your brake servo booster? Looks about the right size and position. Should be a one way valve in that pipe also.
 

sparkyjohnmarky

Forum User
Hi, Mr F,

Been working on the car today, the brake servo is connected to the side of the plenum. I have looked at some vacuum diagrams online and perhaps it connects to the vacuum tank?

This raises another question I have possibly figured out the connections at the vacuum tank, bottom center goes to heater cock, middle left goes to the connection we discussed above maybe, top middle goes to cruise control and middle right goes to the heater motor? I am unable to find any access through the bulkhead of the car.

Thanks again I appreciate the help you have given me.
 

Mr.F

Inactive
The heater controls require a vacuum source inside the car, so there must be a line through the bulkhead. I believe it originates from a central connector on the vacuum tank. There are numerous and complex vacuum lines under the dash!
If you have an original manual, pages HA-3 and HA-5 will be helpful.
The vacuum line to the heater cock is tiny and easily damaged / often perished- critical for good heater operation!
 

sparkyjohnmarky

Forum User
Hi,

I have with your kind assistance now sorted the lines, except for the heater controls. I will have to take the lower section of the dashboard off and see where the line from the vacuum tank originates, as there is no evidence of it in the engine bay. HA-3 and HA5 are very helpful, so there must be a tee connection under the dash with a vacuum tube missing. I have replaced all the lines with silicone tube, so should last longer than the original stuff.

Thanks again
 
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