Problems with chugging and stalling 1976 280 Z

[Redwing]

Hi all,

A newbie here who first posted in wrong area. So here we go again.

I was blessed to have bought a Super Car, a 1971 240Z, when they first came out. At that time there was a 6 months wait, and no choice of color. Tho, luck was with me, and I was presented with one they called Mexican Orange. I drove her for 256,000 miles, trouble free. I've wanted to have that glory again for many years.

Three months ago I was fortunate enough to have my dream come true, a 1976 Red 280Z came into my life. Love that car! But she has some problems, as we all do when we age.

The (1) problem seems to happen mostly when the weather is warmer. Usually the first 30 min. are fine. Altho, twice it has happened in the cool morning, when first started. Suddenly she chugs, gasps, and dies. Occasionally I manage to keep her running. But no amount of effort will restart her. I have found tho, usually after about 15 minutes, she will start and run fine until turned off. Then the cycle resumes. But not all the time, sometimes she will be fine and run perfect after the first episode. Also, there is the time this never happens, and she runs fine from the first minute. But as the weather is heating up, I suspect there will be zero of those days.

I have a mechanic here, but he is not a Z car specific one, and I do not have a lot of confidence in him. He did replace the rack and pinion due to almost no steering at 0-5 mph. But now (2) that is getting harder, going back toward the beginning. His thought is that the head gasket might be needing to be replaced, due to the #6 spark plug being dripped on by the heater hose. Is that extreme? He cleaned and tightened that twice, and finally replaced the hose. The plug still is being fouled up.

There is more I need advice about, but I will end with these (2) for now.

I am asking for your easiest and least expensive fixes. I do have some working knowledge about my car, my Dad taught me with my '71, and can do some of the easy repairs. And I am 72, on social security, I'm sure you know how far that goes.

So Thanks for letting me be here to learn more about my car. I promise to be less wordy next time.

[SteveJ]

From my reply on the other thread:

 

Just reading that there might be a leaking head gasket, my suggestion would be to try to see if there is an old Z enthusiast living nearby (Z clubs are great resources for finding someone.) who could take a look at it. The coolant should be inspected, as well as spark plugs, fuel pressure, compression, etc., etc. 

[siteunseen]

I may have stepped out of line starting a thread for you, sorry.

 

Here it is, http://www.classiczcars.com/topic/51639-redwing-nice-young-woman-needs-our-help/

Good info already on there, we're jumping at the chance to help. 

[Redwing]

GA Thank you so much.

[SteveJ]

If you live in Georgia, send me a PM with your location. I may know people close to you.

[siteunseen]

Two tricks for the forum it took me forever to figure out. First helpful tip is click on the time and date under the last user to reply. That'll send you to the end without having to scroll through all the other replies. You probably know this already but it took me 2 years as this is my only forum participation. 2nd thing is click on VIEW NEW CONTENT, about 3/4s to the right up top.

Hope it helps.

.

[Redwing]

Another thing I should mention perhaps.

Again only noticed in warm weather, the console by my leg gets quite warm. Way too warm to be comfortable.

I do not know if maybe it is part of my main problem, but thought I would mention it.

Also, on eBay there is a Z for sale that has been signed on the hood interior Mr. K.!!!

That should make it real valuable.

[siteunseen]

It could be a stopped up exhaust not flowing properly, causing the hotter tunnel.  Not too sure how to test that though.  Mine pushes a fair amount of air out the rear tailpipe, not a whole lot but you can feel it blowing.

[FastWoman]

I'm going to make a few guesses:

 

The hot tunnel:  Perhaps your engine is running lean.  This can be due to a variety of things.  In a 1976, I think the more likely problem would be vacuum leaks.  If the vacuum tubing is in bad shape (which it usually is on any old car), the best/easiest thing to do would be to replace it all.  You can get new tubing at your local auto parts store.  Next, very carefully check the accordian-shaped boot connecting the airflow meter with the throttle body.  It may have splits in it, which would result in un-metered air.  Lastly, buy a cup of Yotastic yogurt, enjoy the contents, wash out the cup, and do the now famous "yogurt cup test" on your intake, first described this way:
 

 

I pulled off the AFM and plugged the AFM-to-throttle boot with a yogurt cup. I pulled off the vacuum booster line to the brakes and attached a hose to blow through. I pressurized the intake with nothing but moderate lung power, held the pressure with my mouth, and got a feel for how long it took for the pressure to leak away. I then pulled the little HVAC vacuum control line (adjacent to the power brake vacuum line) and repeated the test. I found that the pressure took maybe 5 times as long to dissipate with the HVAC line in place than with it open and blowing air. Pulling that one little vacuum line is not particularly consequential to the fuel/air mix, and any vacuum leaks that might exist (but probably don't) would be far less consequential than that. The small amount of pressure dissipation I could feel was probably the result of air leaking around valves, rings, etc. -- i.e. the air leakage through the entire engine. I highly recommend this method for satisfying yourself as to whether your intake is tight. It's quite quick and easy to perform.

 

 

For a 1996, I think you would have to pull off a different vacuum hose, perhaps the one going to the fuel pressure regulator.  I think you might find that you have a leak between your intake manifold and cylinder head, especially around cylinders 1 and 6.  This is a common problem, and the fix is to pull and replace the manifolds (i.e. with a new gasket).  That's somewhat labor intensive, of course, so let's hope you don't have that problem.

 

 

The problem with your car dying in hot weather is likely due to your ignition module or your fuel pump overheating.  Once they cool down, everything is OK again.  The fix is to replace them.  When your engine dies, coast with it in gear, and watch the tachometer.  Does it still show a reading, or is it at zero?  If it reads zero, you've probably got a bad ignition module.  Another test:  Buy a can of starter fluid.  When your car dies, pull off a small vacuum hose, spray some starter fluid into the intake manifold, replace the hose, and try starting the engine.  Does it fire for a second or two?  If so, the problem is more likely fuel related, and your ignition is probably OK.  And your dad probably showed you the trick about checking for spark:  Pull a spark plug wire, perch it very close to a piece of bare metal, crank the engine, and check whether a spark is jumping between the wire and the metal.  (You might need to extend the spark plug wire's conductive path a bit by inserting a paperclip.)  Check these things immediately after the engine dies, and let us know what you find.  We'll help you from there.

[Redwing]

My battery died overnight. I did not leave anything turned on. My friend came to jump start her, alas no good. He discovered a screw that is attached to the negative pole, was loose. It has 2 small wires being held in place, I don't know where they go.

My question is.... any chance that this loose screw could connect and disconnect (whatever), as I drove along, causing my instant loss of power?

Wish I were more knowledgeable about these 2 wires.

Thanks

[Zed Head]

Probably a ground wire and the condenser body.  

 

Don't let any well-meaning person start tweaking and adjusting things to try and get it to start.  If it ran well before, and now you just have a no-start problem, the solution is probably a simple one, like an ignition module, or bad battery.

 

A picture of the wires and your engine bay would help a lot.  And keeping everything in one thread.  This thread, for example, doesn't have the description of the car dying and not starting.  But the other thread does.

[siteunseen]

Probably a ground wire and the condenser body.  

 

Don't let any well-meaning person start tweaking and adjusting things to try and get it to start.  If it ran well before, and now you just have a no-start problem, the solution is probably a simple one, like an ignition module, or bad battery.

 

A picture of the wires and your engine bay would help a lot.  And keeping everything in one thread.  This thread, for example, doesn't have the description of the car dying and not starting.  But the other thread does.

The two threads are my fault.  Mike hasn't seen my request to merge them, I guess.

 

I agree with Zed Head, don't let your well meaning buddies fix the simple stuff, it does more harm than good in my experiences.

 

Take off the valve cover and take some pictures, other thread  , remove the plugs and take a picture of those as well.  But like Fastwoman says pulling the dipstick is the easiest thing to do at this point.