77-Z

My son's '77 Z is FINALLY on the road after getting new injectors, cleaning gas tank, new plugs/wires/cap/rotor, setting timing. NOW I'm needing some guidance on getting the FUEL/AIR mixture settings correct. Is there an "order" to setting the adjustable screws? Also, how do I set them? (screw with spring on the top of the throttle body. screw on the lower side of the mass air-flow meter. any others?) As it is set now the car doesn't have much umph, even though I have good compression, am running NGK-5 spark plugs, etc. Just want to be sure I'm setting the items that I have control over. Thanks for any assistance. Mark Charlotte, NC

Well, I pulled the valve cover off, thinking I'd visually inspect the timing chain & valves...I found a TON of GUNK (sludge, dirt, goop, etc). I believe this car has sat for quite a while! I sprayed some PB Blaster onto the varnish and tried scraping the gunk away from the areas so I can carefully clean it up before doing further adjustment/inspection. (I'll be sure to change the oil before running the car again in case the sludge and junk drops into the oil pan). I also went to remove the EGR valve since it had a funky gasket on it...when I did I found the base of the EGR was cracked and the hole down to the exhaust manifold was full of rusted crud. I'm thinking I'll put a "block plate" over this? Anyhow, any other thoughts on cleaning up the area under the valve cover, adjusting valves, etc? Also, how do I know if my valve guides are any good? Is there a test or something to tell? Thanks again.

Thanks for the input so far... oz: yes, they're BOSCH plugs (I'll get the NGK as you suggest). Sorry for the pic resolution, I only have my phone camera. The plugs are black/carbon build-up but also were oily upon removal. johnnyO: I suspected "back pressure" also and cut off what I THOUGHT was a catalytic converter (ended up being a "resonator", which was not restricted.) I appreciate your input.

My son's '77 280Z is still on it's way to becoming a daily driver...long, slow process. First we tackled the fuel system (cleaned, sealed tank, new fuel pump, good pressure 40psi to rail, new injectors). Then we replaced all vacuum hoses, cleaned all electrical connections, etc. The car RUNS but there is no power. I thought maybe I had no COMPRESSION, but today I did a compression test and came out with what seems like good compression: (1=150, 2=155, 3=160, 4=150, 5=155, 6=150). The spark plugs were black with carbon and somewhat oily. When it does run it burns a bit of oil. If you have a suggestion I am all ears. Otherwise, I wondered how to: set the proper AIR/FUEL mixture on idle screw and on the throttle body screw? adjust the VALVES I'm attaching a pic of the sooty plugs in case that helps at all. I appreciate any help you can give. -------------------------------------------------

I have a '77 280Z and am replacing all the rotted/broken/missing vacuum lines, but having some confusion regarding a couple: * vacuum lines (2) on BPT( (backpressure transducer) valve? (one goes to EGR, where does the other go?) vacuum line (2) on THERMAL VACUUM VALVE? (two plastic vacuum lines on end of this were broken off and I don't know where the lines should go) It also seems that I'm missing some "one-way valves" (VDV?) that should be spliced into some of the vacuum lines...how important are these, where can I get them and where are they needed? Thanks for the help. Mark

I have a '77 280Z and am replacing all the rotted/broken/missing vacuum lines, but having some confusion regarding a couple: vacuum lines (2) on BPT? (one goes to EGR, where does the other go?) vacuum line (2) on THERMAL VACUUM VALVE? (two plastic vacuum lines on end of this were broken off and I don't know where the lines should go) It also seems that I'm missing some "one-way valves" that should be spliced into some of the vacuum lines...how important are these, where can I get them and where are they needed? Thanks for the help. Mark

The INTAKE BOOT (just after the air filter/just before the AFM) has a large crack in it - will that cause the continual "backfiring" at the AFM (air flow meter?)? If I start the car and then manually hold the pivot inside the AFM it runs smoother. ???

I got some great help posting about electrical problems I had, and now actually have the car running...just not very well or very long! Basically I need guidance to help get the car running somewhat decently so I can actually drive it and hopefully address the many other issues that will need fixed. Here's some background to set the stage: My 17-year-old son LOVES 280Zs, so when he was out of the country on a mission trip I located a 1977 280Z that had been sitting for a while and picked it up for $500. I actually started it up and carefully drove it home (about 30 miles) pumping the brakes the whole time and avoiding main roads. Needless to say that he was in a state of disbelief when he came home to find that he was the proud new owner of a Z!!! The problems began shortly thereafter -- I believe adding a full tank of gas loosened the crud and thus clogged the fuel pump. The pump seemed to get much louder before it stopped running, and after removing the pump and gas tank this was verified. I cleaned the tank, bypassed the fuel sock, added a clear filter between the tank and fuel pump, cleared all gas lines (feed & return) etc. I then discovered a wire had also fallen off the negative battery cable (see 2 red wires post in electrical) which was reconciled the other day. I finally got the car restarted, but it backfires horribly near the MAF? (up near the air cleaner/rubber boots). I know the car needs new vaccuum lines and probably some new wire connectors, but I would think I could get it running for more than a few seconds at this point...Any suggestions of WHERE I SHOULD BEGIN? Thanks! Mark (77-Z)

quick update...the "unattached red wire" WAS the problem and solved several issues: > fuel pump now has constant/proper current > fuel injectors now injecting fuel into cylinders > car actually STARTS! Other issues are now waiting to be tackled but fall under a different category (which I'll post and trust I find the same helpful info I got here) Thanks again! Mark (aka 77-Z) ---------------- '77 Datsun 280Z (son's project/dream car) '61 Ford Falcon (2nd project car) '65 Ford Mustang (wife's 40th bday present) '93 Mercury Villager (my boring work van)

Wal280Z, I appreciate your input to my dilemma - I rechecked the diagrams as well as my wiring and am SURE the other red wire DOES attach to the negative battery post! I happened to find more confirmation via some digital pix my daughter took when I gave this car to my son. Some of the pix showed me standing next to the engine compartment and there WAS a wire attached to the negative battery post when I bought the car (which must have fallen off about the time the car stopped running). My son (Clay, 17 years old today) is the one I bought the car for and we hope to fix the wiring issue asap. I'll post and let you know how it goes. THANKS AGAIN for everyone's help in getting my son's dream car back on the road! Mark ------------------------- The two red wires that I believe you are referring to supply the positive and negative supply from the battery to the FI control unit. The Positive has a fusible link and the negative does not. If I recall correctly, the connectors are (originally) keyed so that the polarity cannot be switched. There is a picture in this thread that shows off my maxi-fuse upgrade, but it does show the battery connection with the two red wires you refer to. The negative is in the foreground, positive (fusible link shown) is beyond. If you need another picture (without the fusible link covering up the connections) let me know. *edit* Both wires *should* go to the FI control unit only - but confirm with the diagram for that.

Thanks for the input... Walter , I found the FSM at the site you posted - it is a great help! =Enigma=, thanks for the guidance on the wiring & attached pix -- I traced both red wires from the battery area to the driver's side fender where they disappear at the base of the firewall. Do they split different ways at this point or tie into the main wiring harness and go through the firewall? I have yet to unwrap the two red wires or any of the harness - not sure the best way to unwrap/rewrap? sblake01, this wiring diagram is awesome and will also help track down the wires - thanks! I'll be sure to repost when I trace the wires and reattach any missing ground. One other question - are "fusible links" available at any chain auto stores or via web only? Thanks again! 77-Z

My son and I are working on a 1977 280Z and are stumped with some electrical issues (surprise!) The primary issue I need help with right now is know where to hook one of the 2 red wires that come out of the wiring harness near the battery. One of the wires has a male connector, which hooks to the positive battery terminal via a fusible link. The other red wire has a female connector but does not connect to anything... I read somewhere that this probably connects to the negative battery terminal, however there are no wires coming from that area. ??? This is a new project car and it's possible a wire is missing or fell off in transit. Any help is greatly appreciated. 77-Z