You mentioned fuel and I don't wan to muddy things up but you might consider a bottle of fuel treatment in case you got some water in the last fill up.  With the help you already have, you should be able to get this sorted. Just keep trying what they ask and feed the results back.

 

Sorry ERR

 

 

72 body and block, everything else 71, Tokico springs, Illumina, R180 CLSD, 83 close ratio, 3.90 gears, Ztherapy SUs, BRE 15X7 Libre wheels and BRE front spoi

2 hours ago, madkaw said:

Just watched the vids and my money is still on ignition. That ignition coil looks like the original . I was go to fuel last . The fact that it happened kind of all the sudden, I would think ignition. 

It may very well be the original coil.... the car is very very stock and original. One family, 2 owners (passed from father to son).

I'll get a look at it this weekend or sooner and let you know what I find.

4 hours ago, jonathanrussell said:

It worries me a bit that the prior mechanic wrote that they leaned the mixture. There really isn't a way to do that without screwing with the AFM which causes all sorts of other problems. Hopefully he did nothing. 

 

The lean mixture notes concern me as well.... I reviewed the recent (10 years) worth of service records and those notes were on the last bit of work performed before smog and sale to me. Sounds a bit suspect.

Best to get this sorted out now. I understand that a properly maintained FI system is pretty much bulletproof, so I'd rather get this straightened out first.

The idle air bypass screw is under the rubber plug on the side of the AFM.  It is used to lean out the idle mixture by letting air past the AFM vane.  In later years Nissan put a solid cap over that screw so it couldn't be adjusted.  But 1976 still made it easy.  It's a fairly easy and common adjustment for idle.  Not sure I'd read too much in to it for your year.

Didn't realize that the car was not driveable.  You said that it smoked, and died, but it seemed like it was repeatable after eventually restarting.  Now you say it's "not running!"?  Anyway, good luck and don't expect a miracle cure.  You'll probably have to check a lot of things that check out just fine before you get to the one that isn't.

 

"The car has not been running much at all for 2.5 months, I drove it a whopping total of 4 times....... mostly neighborhood drives less than 10-15 miles aside from the 75 miles drive home after initially purchasing it.

I have not had a chance to beat on it, I would like to really drive it.... BUT IT'S NOT RUNNING!"

18 minutes ago, Zed Head said:

Didn't realize that the car was not driveable.  You said that it smoked, and died, but it seemed like it was repeatable after eventually restarting.  Now you say it's "not running!"?  Anyway, good luck and don't expect a miracle cure.  You'll probably have to check a lot of things that check out just fine before you get to the one that isn't. 

Well if you call a car that starts, idles roughly, then dies, and will not start again drive-able... then yes it is drive-able.

I wouldn't take this car out on the street because it will die, not start and then I'd have to try and push it up the hill of my driveway back into the garage. In my book, that is not drive-able.... and therefore not running. (meaning NOT SUITABLE FOR ROAD DRIVING).

Quote

Anyway, good luck and don't expect a miracle cure.  You'll probably have to check a lot of things that check out just fine before you get to the one that isn't.

Never asked for, nor expected a 'miracle cure'. I do expect to have to run through the FI system diagnostics. Thanks for your input ZedHed, I'll take it into consideration and let you know when I got it all sorted out!

Edited March 19, 20196 yr by mbz

On 3/17/2019 at 1:43 PM, mbz said:

Bought the car in late Jan. 2019, car passed emissions test and it started and drove fine until 2 weeks ago when problem first occurred.

Engine runs very rough for about 1-3 minutes at high RPM when gas pedal is pressed, and exhaust kicks out white-ish / light gray fumes.

When gas pedal is released, engine dies, car will not idle.

Try to start again and engine cranks but will not start.

Let it sit for 1-2 hours and it will start again, same as above.

Only responding to what you wrote.  Good luck.  

13 minutes ago, Zed Head said:

Only responding to what you wrote.  Good luck.  

Thank you ZH!

another thing to read up on in the FSM is the EGR (not sure what years and what model had it), any way study up on that as well, it can cause a lot of issues with rough idle esp when the engine is cold. I don't think it would be a rich run problem, but often times there is one problem masking another. Just work you list, check them off, and then study the EGR and test it if you still have idle issues when done with the list. Just did not want to forget that one. Deleting it is often done, but I would not recommend that, I have heard CA is very on top of illegal modifications. Besides IHMO a working EGR is not a performance robbing system anyway, if anything can help from what I have read.

16 hours ago, Patcon said:

You mentioned fuel and I don't wan to muddy things up but you might consider a bottle of fuel treatment in case you got some water in the last fill up.  With the help you already have, you should be able to get this sorted. Just keep trying what they ask and feed the results back.

It was a while back when Jai's car Redwing had these similar symptoms, twice, and after checking and following excellent advice from these members it turned out that bad gas (water in fuel) was the problem.  I too have recently experienced bad gas after fill up and now I know it's not that uncommon an occurrence.  A simple and inexpensive elimination of that possibility would be like Patcon suggested.  Instead of draining the tank to check, a bottle of Heet from the auto parts store or a 16oz bottle of 90% Isopropyl Alcohol in the gas tank will disperse any water in there allowing it to burn out.  It should't affect any other diagnosis. I'll add that in both of Jai's and my problems,  It was the pruchase of Ethanol free gas from pumps at gas stations.  Fingers crossed! 

OK here are the photos of the new spark plugs.

I have to get to work, so please review photos and let me know your questions and/or comments, I will review & respond later this evening.

THANK YOU ALL!

I APPRECIATE THE HELP & INPUT VERY MUCH! ?

(ps: MadKaw - I did a quick visual inspection of the outside of the distributor cap and saw no cracks, will do a more thorough inspection when time allows).

if that was just a short time run, seems too rich. Those insulators should come out nearly white. I suspect an  overly rich condition.

I recommend the FPR test (pressure engine off, pressure eng on, gas leak from vacuum line, then the Temp Sensor Test, then the CSV (make sure its not leaking for firing, prob warm enough that it should not).

OK so I got a chance to do a quick test of taking the oil cap off while idling.

Engine runs better WITHOUT the oil cap on, then goes back to rough idle when oil cap is replaced. (see video)

Also, with the oil cap off, the car starts and runs just fine. I repeated this 3 times consistently to be sure. (no video of this)

I'm thinking at this point that I really need to focus on the Fuel Pressure Regulator as ZedHed and DaveWM indicated, however I am still planning on checking the distributor cap, spark quality, spark cables and ignition coil as well because the engine runs rough at higher RPMs (2000-3000 range).

One last item of note; after sitting in the garage doing nothing for 24+ hours, the vehicle has a faint gas smell. I mention this because I am wondering if this may be a slow fuel pressure leak related to a failed FPR...?

Please take a look at the video below and advise of your comments.

I truly appreciate of all the help from the group.... thank you!