Odd power loss on occasion........

[70z4fun 4]

Greetings all,

So, a quick overview. I have a series one 240z, which is basically stock. It does have a updated coil, but still runs points and stock fuel pump.

I have had this car for over 40 years, and it has been reliable over the years. I don't drive it as much as I should, but over the last few years, it has had the periodic power loss, then dies. It "feels" electrical, or like when half a bank of cylinders goes out on a newer car, just losses power then it just dies. 

I can restart it after a few minutes, but have had no luck fixing the issue. When it first happened, I changed the points & plugs, then it happened again, and I replaced the condenser. Ran fine for the next few hundred miles, then acted up again. Checked the carbs, switched the coil. Ran fine again for awhile, then it happened again. Changed the fuel filter and  pump, Filter looks clean and always use ethanol free fuel.  Well that was it's own episode, after 40 miles, it died, and was not pumping fuel ( bad fuel pump) and replaced it with the old one, and it started back up, ran fine for another few hundred miles, then on my way to work yesterday, it did it again. Got it started, got to work. Ran fine going home.

So, looking for solution. I am thinking I should rebuild the carbs, maybe it's the spark plug wires?  Maybe the fuel pump?

Just guessing at this point. I can't make it happen on demand, and it does not do it when I get it started. I thought maybe it is starving for gas, but it always restarts. So, looking for some other suggestions that I am not thinking about.  Car runs great when it's running,  so not sure what would cause it the loss of power. IF it was a newer car, I would think computer issues...... but it's a 1970 240z...........

Any thoughts are greatly appreciated.

Enjoy

Edited October 26, 2020 by 70z4fun

[Zed Head 2,194]

Sounds a lot like loose crud clogging the inlet line screen in the fuel tank.  The crud gets sucked on to the screen and clogs it then floats free when the engine dies.  You might drain the tank and see what you find.

Edited October 26, 2020 by Zed Head

[siteunseen 3,416 5 Vehicles]

12 hours ago, 70z4fun said:

Greetings all,

So, a quick overview. I have a series one 240z, which is basically stock. It does have a updated coil, but still runs points and stock fuel pump.

I have had this car for over 40 years, and it has been reliable over the years. I don't drive it as much as I should, but over the last few years, it has had the periodic power loss, then dies. It "feels" electrical, or like when half a bank of cylinders goes out on a newer car, just losses power then it just dies. 

I can restart it after a few minutes, but have had no luck fixing the issue. When it first happened, I changed the points & plugs, then it happened again, and I replaced the condenser. Ran fine for the next few hundred miles, then acted up again. Checked the carbs, switched the coil. Ran fine again for awhile, then it happened again. Changed the fuel filter and  pump, Filter looks clean and always use ethanol free fuel.  Well that was it's own episode, after 40 miles, it died, and was not pumping fuel ( bad fuel pump) and replaced it with the old one, and it started back up, ran fine for another few hundred miles, then on my way to work yesterday, it did it again. Got it started, got to work. Ran fine going home.

So, looking for solution. I am thinking I should rebuild the carbs, maybe it's the spark plug wires?  Maybe the fuel pump?

Just guessing at this point. I can't make it happen on demand, and it does not do it when I get it started. I thought maybe it is starving for gas, but it always restarts. So, looking for some other suggestions that I am not thinking about.  Car runs great when it's running,  so not sure what would cause it the loss of power. IF it was a newer car, I would think computer issues...... but it's a 1970 240z...........

Any thoughts are greatly appreciated.

Enjoy

I agree with Zed Head with sporadic running on an older car.

I can share my experience with a cruddy fuel tank on a 240 I bought that had been sitting for a long time. When mine died out I could pull the suction side hose off the fuel filter and blow back through it until I heard bubbling noises in the tank. Reconnect the hose and go like hell trying to get back home. It wasn't rust as it didn't stick to a magnet, just cruddy fuel. I had to drop the tank and clean it then I coated it with Red-Kote tank liner. has been fine for 4 years now? Try that, maybe it'll help you get closer to figuring it out.

After acid cleaning...

After Red-Kote...

[70z4fun 4]

Thanks  for the feedback, 
Interesting thought. I didn't  think about the fuel tank since the fuel filter looks clean and it has fuel in it. But I am not  in the engine compartment when it happens 😉

Is there a way to look inside the tank without removing it and see anything useful?

I also was not aware there was a screen at the tank end. I have never yanked the tank since I have it, but alway "think" I am in good shape since I use ethanol free fuel.

I would think if I am going to pull the tank, I should plan on doing the sender and hoses. I did do the evaporation hoses many years ago.

 

[240260280 2,151 1 Vehicles]

Next time it dies, check immediately for spark to rule out ignition.

Method 1.

Coast with foot off clutch and see if rpms are up or at zero

 

Method 2

Just open hood, pull hv wire from the centre of the distributor cap and place its end close to a threaded bolt at the top of the strut tower.

Crank the engine and watch for a spark to jump. 

(You may need a small screw driver to push up into the end of the HV wire and place ~ 1/4" away from the bolt for the spark to jump)

 

You can also easily put a filter near the tank

http://atlanticz.ca/zclub/techtips/fuel/g3filter/index.htm

Edited October 27, 2020 by 240260280

[Mark Maras 1,105]

Good advice above. You could also carry a can of starting fluid with you. When the engine dies, give it a shot and see if it starts.