1977 280Z Miss firing after engine is warm.
 

Good evening everyone,
I have acquired a 1977 280Z with L28E. I have worked out couple of electrical kinks to the point that the car will now start and idle.

The first 30 seconds of it running are flawless and then you can hear as if it stops firing on cylinders 1 and 2, when both plugs removed it makes no difference to idle. When I take it for a drive it sometimes runs smooth but will lose cylinders when under load.

Things I have done.

• Fuel Pump
• Fuel Filter
• Converted fusible links to fuse box
• new ignition wires
• new distributor cap
• new ignition coil

Things that help the idle and miss fire, timing advanced as far as it goes and AFM fingered to make the car run rich.


I need some more suggestions, because I am running out of ideas.

Thank you

Have you tried cleaning your injectors?

I figure that one is ruled out since the car does run excellent on 6 cylinders while its cold for those 30 seconds, it does the same thing with the cold start valve unplugged.

Runs all nice and smooth with acceleration, then as if it hits a certain temp and it loses power and miss fires.

Things expand when warm. If you've got a constricted line or orifice, the gunk could clog things up after it gets bigger. Running some fuel injector cleaner through probably wouldn't hurt.

Have you checked for spark on the missing cylinders? If it's there, you probably have a fuel problem.

BTW, I'm no expert on FI motors, just know some of the basics.

found the problem. Fuel feed line from tank was aerating the fuel.

any one know if its worth getting this tank torn apart or just get a generic racing fuel cell tank?

Impressive. :icon_super: Kind of makes sense with your symptoms.

How did you figure that one out?

Well i noticed that when the fuel pump would shut off the tank would gurgle. I googled it and others are having problems with internal tank hose deteriorating and aerating the fuel.