1977 Datsun 280Z

[Willisf]

My wife has a 1977 Datsun 280Z. We've had some issues with it in the past.... Replacing parts here and there. It runs.....but not as well as it should. Here's the problem.... When we go to give it gas, it sputters and seems to be missing to a degree. Also wants to stall when giving it gas ..... All this while going down the street, not just revving it up when parked. We've replaced the plugs, checked the spark plug wires, ran a compression test, vacuum hoses checked..... Even checked the injectors.... New gas and all. We are about at wits end on this..... I'm sure it is a simple fix. I'm not wanting to take it to a dealership...most of the techs here don't seem to know much about a straight 6 with fuel injection. Any insight would be great. Seems to running a tad rich.

Thanks in advance!

[Sailor]

Of course i can't say anything for sure from a distance. If the spark plugs work and give a decent spark (easy to check) and the fuel runs ok then i would go and check the ignition timing and fuel filter.

280Z is a beauty. The older the better imho.

[Willisf]

Glad ya like the car....she is very nice and a looker too!

I'm thinking it's a fuel issue too..... The fuel lines was cleaned by my son in his shop class.... But don't think they checked the fuel filter. Guess we can check the timing too.

[Euclid440]

Check for water in the gas, old cars that sit, especially without full tanks are notorious for commendation build up in the tank.

If it has been sitting drain the tank (and check your fuel filter(s) or by pass the injection and fill a container with some gas from the fuel pump to look for water. A defective or torn diaphragm in the fuel pump may be the cause.

Sta Bil in the tank is cheap insurance.

[Willisf]

Gas tank was completely emptied.
We put sea foam in the tank......
I'm thinking it's a fuel filter problem...... Heading over a friend's place to check it more in detail.
Knows more about cars than I do.
So many variables in what could be wrong.

[AntiqueHoosier]

Try 4oz of Marvel Mystery Oil next time you put 10 gal of fuel in the Z.

[MikeB52]

77, nice ride..
Should be carbureted, not injected fir its age. Fuel filter, good place to start.
Timing, vacuum advance, leaks in intake manifold, carb itself for proper idle jet setting.
Wish I was closer, loved the old Datsun's. Also see if your friend can check the throttle for correct operation at WOT. vac advance and extra fuel squirts went hand in hand on those. Replace the air filter with the fuel filter first step.
Let us know the results..
Cheers and good luck.

[Sailor]

By all means i'm not a remote healer but i've worked with mc, car, truck and ship engines and techniques for almost all my life. As long as there's not electrical brain it's usually only logic to solve the problem. Although not always. And even with modern engines EDB reader or engine control hard/software will tells a lot.
I've met some unbelievable problems, specially with Italian and French cars or motorcycles.

Condensated water in the tank surely causes problems but they occur through the whole rpm range. If the engine runs ok with the idle rpm's and the problems occur only when giving your car some pedal. Then the problem is something that depends on what happens when giving your engine more rpm.
In such situation your engine wants more gas, air and the ignition system needs to follow the demand of the rising rpm. Something that works ok with idle rpm but not when situation changes.

I do not believe that putting some miracle liquid to your tank solves the basic problem but that is just me. Cleaning the carburetor, changing the fuel & air filter, cheking the distributor systems and 99% of all possible causes will go eliminated.

[Euclid440]

When you drained the tank, did a lot of debris come out?

The Sea Foam, also may have also knocked some stuff loose.

Sounds like the fuel system may be contaminated. Start with a large see-through after-market fuel filter. It does not take much to clog the injectors.

Good looking car, don't see many now days... They were rocket ships.

Also check you fuel pressure from the pump.

[Utopian]

77, nice ride..
Should be carbureted, not injected fir its age.

Despite the era, they were fuel injected.