I'm a little stumped atm. My Z will start and run roughly for a little bit then eventually fall flat on its face and not restart.

I pulled the fuel line and it sprayed everywhere (this is after sitting for like 2 days!) but when I put the tester in line it built to about 15 PSI and was very very slow to build.

Now I would say bad fuel pump but heres where I think the issue is. I can hear bubbling in my fuel filter. Like the tank is nearly empty. But I know theres 5 gallons of new gas in the tank so where in the system can it be pulling in air but still getting fuel? Without leaking on the ground!

 

Have you checked your fuel pressure regulator?

 

Yeah the FPR doesn't leak and holds a vacuum.

 

Doesn't leak as in you've done a leak down test to see if it holds pressure for a few hours?

Could be rust in the fuel tank... Have you replaced the fuel filter? Can you test the pressure before the filter?

 

I didn't bother trying to hold vacuum pressure on the FPR for a few hours. but the pressure that came from the line after sitting a day was pretty strong. Shot fuel everywhere.

Fuel tank is clean. I drained it and washed it. And I just put a new fuel filter and engine bay fuel lines. So I never bother testing the pressure before the fuel filter sense its brand new. I put it on after i cleaned the tank.

 

Fuel pressure... not vacuum. Does it hold fuel pressure for several hours?

15psi is not "strong".

I'd say it's the fuel pressure reg. Have you checked voltage at the fuel pump? Is it 12V+ all the time?

 

Alright alright. That still doesn't answer my question as to where air is getting into the system BEFORE the fuel filter.

I'll cap the line and test the pressure from the pump itself.

 

Check the pickup tube in the tank. If it has pinholes, it could be letting air in.

 

Eh, I was afraid of that one TBH.... I REALLY hope their ok. I dont feel like dropping the tank to find out....

 

Ok its not the FPR. And the fuel pump looks fine after I cleaned it. but still not getting hardly any pressure.

Gonna try filling the tank over the level of the pickup lines and see if that fixes the issue. Then I know I need a new tank.

 

Yup. Sure enough added enough to cover the lines inside the tank it starts up and runs just fine. Dropped the tank and cleaned it out then looked inside and found rust to the degree it ate through the pickup line at its highest point....

I'm not sure how to fix that....

 

Search around at Classiczcars.com. That's where I learned about the issue with the pickup lines. You might have to find someone to fab a new pickup line for you.

 

If I could get back out to SLC theres 2 78 280Zs out there. I just dont have time to get out there... Ugh

 

Well $80 I have a spotless working fuel tank!

Now Im running so damn rich it kills the engine....