The picture is worth a thousand words.  Barb fitting appears to be 1/8 NPT ?  Please correct me if I am mistaken.  Also I know the FPR stands for the fuel pressure regulator, but not sure about the CSV designation.  I will certainly need to do some more homework on the plumbing.  The original FPR on the 78 has 3 barbs.  I believe 1 is the vacuum and the others were the in and out lines.  I may have it all wrong in my head.  That happens quite often.  Thanks for any additional clarification and help, John-Lugoff, SC.

I believe CSV is Cold Start Valve

CSV is the cold start valve, on my rail it is fed from a dedicated port on the fuel rail.  you are correct on the 78 fpr, mine is mounted on the firewall with injector hose from the output of the rail.  The other side goes to the fuel return line.

Thanks for the info on CSV.  Should have figured that one out for myself.  My mental image of the CSV is on the other end of the intake.  I guess it really does not matter which end supplies the fuel to the CSV.  Looking forward to this modification project and sourcing the aluminum fuel rail material, good quality barbed fittings, and the challenge of the drilling and tapping.  Suggestions welcomed, John-Lugoff, SC.

Just tried to fire my 280 for the fist time. Sitting 12 years plus. Replaced pump OE, injectors, all rubber lines. Pressure gauge. Cleaned and or replaced everything feasible that looked worn and or deteriorated. I had the tank cleaned and lined. Have not installed the tank as of yet. Want to restore the rear suspension first allowing more room to work. I tried to crank the engine using two fuel cans. Supply and return. The results were it fired and quit over and over again but would not run. This is what I found after trying to crank the motor.

36 psi holding for two or three minutes then dropping down considerably after a few minutes. 

The return can had a lot of fuel in it. Almost as if it was bypassed directly back to the tank.

Have decent spark coming from the original coil. Rotor and cap look ok. Could be the original wires.

Does it sound like the FPR is stuck in the open position. Everything on the vehicle is original. I’ve owed it since 1984.

any help would be much appreciated 

 

 

 

7 minutes ago, Yarb said:

Just tried to fire my 280 for the fist time.

What year is it?  Not all 280Z's are the same.

You might do better to start your own thread instead of piggybacking on old ones.

Sorry, new to the site. I can go back and start a new thread. It,s a 78 

Sounds like it's starting on cold start valve gas, but the injectors aren't opening to keep it running.

Might also be the oil pressure switch or alternator.  Try removing the oil pump sensor connector.  This will cause the fuel pump to run when the key is on so watch your cans.  The pummp will stay on so you'll know if it's a supply problem or something else.

How long does it run for during each start attempt?

Won’t run more than 4 or 5 seconds and it’s not smooth. Are you talking about the oil pressure switch they mention in the FSM?

Yes, the switch and sensor are combined in one unit.  Just pop off the plug at the round sensor/switch on the side of the engine block..  Turn the key on and the pump should start running.  It's a good test of the fuel pump control system.

During this procedure will the fuel normally bypass the regulator and go to my return tank? On Initial turnover I’m getting 36psi and after it sits for a few minutes it drops down to 10lbs static. Meanwhile I’ve sent a lot of fuel to the return tank.

Try clamping the return hose off. Needle nose Vise Grips with rubber hoses on them work for me.

Don't completely close it off, work up a little at a time.

Edited November 3, 20195 yr by siteunseen