ramsesosirus Posted October 13, 2008 Share #1 Posted October 13, 2008 Just bought a 76 280Z which will be my daily driver for a year or so. Not perfect, but I have the same feeling as when I bought my 87 Monte SS, really excited! There are two main issues I am concerned about right now... 1. Car runs rich, ie blackish smoke from exhaust. It is fuel injection. I put new plugs in (NGK) and new fuel filter (purolator). Can someone lead me in the direction to fix this problem? Gas is too expensive to waste! I was thinking along the lines of a sensor or the coil, etc.. 2. Heater/ defrost doesn't work. It blows air, not hot though. Defrost selector won't work, never blows air out windsheld vents, just vents. I am thinking heater core, maybe the heat door is stuck closed, and for the defrost I don't know. It will get COLD here so it is pretty much a necessity. The two vacuum lines from the firewall by battery are broken and I can't find any open ports or diagrams. I am 99% sure these are the two vac lines from the heater/AC control. Where did these connect to? Thanks a lot, I am looking forward to working on my Z! I also have an 87 Monte SS that I have partially restored all by myself, which I am very proud of, so I am pretty mechanically able and willing to get dirty to fix em. Link to comment Share on other sites More sharing options...
sblake01 Posted October 13, 2008 Share #2 Posted October 13, 2008 Likely the richness is caused by the temperature sensor. Could be leaky injectors or a problem with the thermotime switch/cold start valve however. Here's a link to the full 1976 280Z factory service manual. If you don't already have one, most, if not all, of the troubleshooting info you'll need is in it.http://www.xenons30.com/files/FSM/76_datsun_280z.zip Link to comment Share on other sites More sharing options...
ramsesosirus Posted October 13, 2008 Author Share #3 Posted October 13, 2008 Thanks man, yeah I downloaded that manual online but didn't realize it has a troubleshooting section. The cold start thing is a good place to start. You seem to be the Datsun guru around here! Love that truck you got too.Thanks Any ideas on the heater? Link to comment Share on other sites More sharing options...
Arne Posted October 13, 2008 Share #4 Posted October 13, 2008 I think the heater control valve is vacuum controlled on a 280Z, as is the the doors that diverts airflow to the defrosters. So fixing the vacuum lines may fix both heater issues. I would hope the manual you downloaded has info on that as well, as I don't know much about the 280Z system past this. Good luck! Link to comment Share on other sites More sharing options...
Sailor Bob Posted October 13, 2008 Share #5 Posted October 13, 2008 (edited) I agree, pretty well all the trouble I have experienced with my 280 heater controls have been related to the vacum lines - if nothing else that is the best place to start. Once you replace those lines you should take a good look at the remainig ones right back to the manifold, because even a small crack will fool up the entire system. The last time I had trouble it was a crack by a tight bend near the accumulator tank - I had to disconnect all the joints and inspect them to locate the problem. Probably just as well to replace all those lines and connections - 30 year old rubber it's going to fail eventually (probably sooner than later). Edited October 13, 2008 by Sailor Bob Link to comment Share on other sites More sharing options...
sblake01 Posted October 13, 2008 Share #6 Posted October 13, 2008 Thanks man, yeah I downloaded that manual online but didn't realize it has a troubleshooting section. The cold start thing is a good place to start. You seem to be the Datsun guru around here! Love that truck you got too.Thanks Any ideas on the heater?No problem. Thanks for the comment on the truck. As far as being a 'Datsun guru', thanks for that too, but,....well I know the things I've come across and solved on my own cars but there are others here how know far more than I do. Link to comment Share on other sites More sharing options...
Arne Posted October 13, 2008 Share #7 Posted October 13, 2008 ...I know the things I've come across and solved on my own cars but there are others here how know far more than I do.I think that describes most - if not all - of us... Link to comment Share on other sites More sharing options...
ramsesosirus Posted October 14, 2008 Author Share #8 Posted October 14, 2008 Sailor Bobso those 2 lines from the firewall connect to somewhere in the manifold?? LIke I said there doesn't appear to be any open ports and the manual I downloaded doesnt seem to help with the vac lines; Could you take a look under your hood and see where they go? The lines are not cracked, but they stop right above the manifold. Can I just put a Tee in there somewhere; will any vacuum source work???THanks Link to comment Share on other sites More sharing options...
sblake01 Posted October 14, 2008 Share #9 Posted October 14, 2008 (edited) Check out pages AC-6 through AC-13 in the Air Conditioning section of the manual. Alco page AC-62. The vacuum source is the barb on the intake manifold just in front of the EGR valve and brake booster hose connector. Edited October 14, 2008 by sblake01 Link to comment Share on other sites More sharing options...
ramsesosirus Posted October 14, 2008 Author Share #10 Posted October 14, 2008 (edited) Ok this barb is where the hose for the fast idle valve is attatched, can I run a tee from this to all 3 lines and get the required pressure?? I checked the manual, there should be 2 vac hoses from the heater control in the engine bay, right?? but only one barb/port? Edited October 14, 2008 by 280ZSS Link to comment Share on other sites More sharing options...
sblake01 Posted October 14, 2008 Share #11 Posted October 14, 2008 My car has aftermarket air so it isn't set up that way but looking at the diagram, it looks to me like there is only one line connected to the manifold. The others appear to be connected to the magnet valves which, in a round about way, draw from that one manifold connection. Link to comment Share on other sites More sharing options...
Sailor Bob Posted October 14, 2008 Share #12 Posted October 14, 2008 I can only work by memory right now - I am on a ship about three hundred miles offshore. I have a good memory but it's very short. I will check to see if I have any pictures. There are lots of guys here with 280s - I expect someone can post a couple of pictures. Link to comment Share on other sites More sharing options...
Yarb
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