Problems with chugging and stalling 1976 280 Z

[Zed Head]

Script flip!

Take some more pictures of your motor, top drivers side would be nice, add them to your gallery. We can copy & paste from there. Pictures are priceless to us helping you, It's like a game of chess, figuring out problems. I'm not too good, tic tac doe is my game.

There are two engine pictures there now.  I see one potential problem right off the bat.  The wires to the battery.  Probably not the cause of the engine problem but they look bad.  I assume it's the negative terminal although I can't be sure.  That exposed junction probably would have shorted by now if it's the positive.  But usually it's the positive that corrodes like that.

 

The PCV hose from crankcase look unusual also but maybe that's the rerouting that Nissan retrofitted in 1977.  It looks like the original hose connection is plugged.  

 

The battery connection alone suggests that the engine has not been maintained at the highest level.  So there's hope that the cause of the problem is a simple one.

 

Isn't it tic-tac-doh!..? 

[FastWoman]

Pretty car!  FAIW, it's got a '77/'78 bumper and molding on the front -- probably wrecked at some point.  Then again, with cars these old, it would be unusual to find one that has never been wrecked.

 

The engine bay photo is pretty fuzzy, but there does seem to be an assortment of hose types, suggesting that replacements were only done when a leak or break was discovered.  I'd recommend replacing all of that junk with new.  It should cost all of $15.

 

The wiring repairs are also pretty amateurish.  There are probably some good youtube videos on making wire junctions -- small learning curve + a minimum of equipment -- not rocket science.  My usual approach is to crimp, fill with solder, and then insulate/seal with marine-grade heat-shrink tubing (which you can buy at Harbor Freight).  I'd remove all the nasty looking splice work and replace with new lengths of wire.  And depending on the condition of the electrical connectors, I'd replace those with new ones from ebay (search for "280Z injector connectors").  The 2-wire ones are readily available.  The 3-wire (throttle position sensor) is available from more modern vehicles in the wrecking yard (e.g. Volvos).  The large airflow meter connector is probably fine, and you would have a hard time finding a good replacement anyway.  And you should take a look at your fusible links (under clear plastic covers on the passenger inner fender).  They might be crusty and unreliable.  The covers are often gone, exposing the contents to moisture/corrosion.

 

You should pull off the battery cables, clean up the posts and connectors, clean the top of the battery, install felts, grease the cable clamps, and reinstall.  Heck, you could probably use new cables, judging from the corrosion.

 

All of this is detail work that you can do with a minimum of tools, knowledge, or strength.  You'll probably eliminate a few problems in the process, without even knowing you did it. 

[FastWoman]

Er... a bit of clarification...

 

Leave the fuel lines alone for now.  I'm simply talking about all the vacuum tubes/hoses.  Also, when you replace anything, whether it's a tubing or wire, do it one tube/hose/wire at a time, so that everything stays hooked up the same.  This assumes everything is hooked up correctly, which it might not be.  But you can find that sort of information in the downloadable factory service manual.

[Redwing]

Siteunseen

My tach apparently does not work. Or, when my friend started my battery he found 3 loose wires hanging in the lower left front side of the motor. Maybe one has something to do with the tach. He could not see where they go, so he left them. Thank goodness. Someone posted a link to the best fixes on 280's I think yesterday, or Wed. I was reading them. (Cannot find them again.) They are so technical and involved. Makes me fearful of anyone touching my Z. He works for Shaw carpeting, a mechanic on their trucks for 13 years. But working on a semi and a Z might be like Venus and Mars alike. He is willing to work on my Z, and now I am afraid to let him since I read all that. I met him when he stopped me in a perking lot, and asked if she was for sale. I get that every time I take her out. HA!

So, back to the tach, any ideas?

[Redwing]

Zed Head

I am sorry, I answered about the tach to Sightunseen. Please read it there. Sorry Sightunseen.

The battery is cleaned up. It was the negative pole. He also tightened the 2 loose wires on it.

[Redwing]

FastWoman

I read your information in your post #22, and appreciate your helping me. As I do read all info I can get my hands on. It will take me a bit to gather things and dig into this, but have faith, I will. I also will get better engine photos. Strange you mentioned the fuse able links. When I got the car, the one closest to the firewall was missing. I did a search for what it was, then got one off eBay. This was before I joined this group. I knew if one was there, the other one needed covered too.

You posted a link to StickyEFI, and it was good too. At the bottom of his text, he had another link to EFI and fuel.htm. All I can say is Wow. Very informative and technical. That for sure instilled the fear of a half way mechanic working on my Z. I do not know how I will get the difficult stuff done, but it will not be attempted by the wrong person.

Oh yes, I have suspected my Z was in an accident or more. Bondo under the LF wheelwell, and the hood slightly misalligned. So I am not surprised about the bumper.

Thank you for all you have shared with me.

[siteunseen]

Hey Redwing.  When I first got another 280 after 20 something years of driving other more expensive little cars with round headlights I read everything I could find.  I knew more about the "cars" than I did the one in my garage.   

 

I'm gonna guess this is the helpful tips you found, http://atlanticz.ca/index.php/tech-tips.html

He has a '77 280, lucky for me, and likes to take pictures, lucky for us all.  You should bookmark that link, I use it just about everyday.  It has a  EFI & FUEL sub topic. 

 

My 240Z had a black wire that was loose at the distributor.  When I hooked it up my tach came back to life.  It runs to the coil also.  Can't say for sure if was black with a white stripe or solid black, sorry, but that's probably your problem.  Look around the coil and the ballast resistor, driver's side fender.

 

[Redwing]

Zed Head

I am sorry, I answered about the tach to Sightunseen. Please read it there. Sorry Sightunseen.

The battery is cleaned up. It was the negative pole. He also tightened the 2 loose wires on it.

[Redwing]

Zed Head

I am sorry, I answered about the tach to Sightunseen. Please read it there. Sorry Sightunseen.

The battery is cleaned up. It was the negative pole. He also tightened the 2 loose wires on it.

[FastWoman]

Hey Jai,

 

I'm glad you're still with us!  Hang in there, and you'll eventually learn the motor.  Reading and re-reading the beginning of the EF section is the very quickest way to learn.  Good material!

 

Glad you have your battery posts cleaned up -- making progress.

 

The dead tachometer is an interesting observation.  This wouldn't be from a wire that's not hooked up at the coil or distributor.  The engine does run, usually, and for this to happen, the ECU (engine control module -- the "computer") has to get an ignition signal.  This is done with the exact same wire that feeds the tachometer -- a wire that branches somewhere under the dash, as I recall.

 

One possible reason for your tach not working is that the connection is dropped somewhere, but it wouldn't be at the coil.  Perhaps under the dash?  Another possible reason might be that the ignition is weak.  I've not heard of a weak ignition not triggering the tach, but you never know.  It would be interesting to know how long a spark your ignition can create.  If you can create a pretty long spark, and if your engine does run, the tach should also have all the signal it needs (assuming it is hooked up).

 

Can you photograph the wires that are hanging for us?

[Redwing]

Within this subject, someone and myself mentioned a large Whoosh when opening the fuel cap. Well, mine is so severe, that the other day it started with a loud Whistle then the Whoosh. I have been opening the cap slightly as someone suggested. But apparently this time the vacuum sealed it back.

Any ideas?

Thank you

[Redwing]

I do not know if I can photo where they are coming from. They dangle down from up in there somewhere.

My son has some small ramps I can use so I can slide under the car, to check if I can see what the connected end is attached to. I will try shortly and let you know.

Thank you