1976 280z engine runs rough then dies, will not idle.

[Mark Maras]

 Rev the engine to above 2000 RPMs and check the voltage again. It should rise to 14 + volts.

[mbz]

Dave WM, here it is:

Fuel Pressure with fuel return line disconnected and Engine Running: 41.5 psi

So just short of taking the FPR out and testing it, this is most likely a failed FPR....? (like 99% chance)?

If so, I'm thinking I'll just order one and swap it out and see if that fixes the issue.

Is the FPR something that would take some time to fail and would cause the engine to run rich and gradually increase fuel pressure until the FPR ultimately fails?

[Dave WM]

and that is with the pressure gauge connected between the fuel pump and the fuel rail.

do one more test with the starter disabled (solinoid wire pulled off), key to start (so engine off but pump runs) this time disconnect the cold start valve connector so it cant fire. Get a reading while the key is in the START posistion. You need to read it while the key is held in start while the pump is actually running. It will drop the instant you release the key. you want the pressure while the pump is running.

I just want to see that odd ball low reading one more time.

Edited March 31, 2019 by Dave WM

[Dave WM]

sorry my bad, the gauge is between the fuel FILTER and the pressure rail. or just take a pic of the setup

Edited March 31, 2019 by Dave WM

[mbz]

Hi Dave WM,

Yes the fuel pressure gauge is inline right after the fuel filter going into the fuel rail. (easier access)

OK so I just disabled starter, disconnected electrical to CSV, and held the key to the START position.

The fuel pressure gauge reads 43.5 psi

Edited March 31, 2019 by mbz

[Dave WM]

ok that ties it, new FPR time IMHO.

[mbz]

OK thank you.

I'll order one today and install when next available opportunity to work on car.

Purchasing question / advice solicitation: Buy the $50 FPR from Rock Auto or spend $30 more and get one from O'Reily with a lifetime warranty?

Or any other purchasing suggestions / recommendations?

[mbz]

2 hours ago, Mark Maras said:

Rev the engine to above 2000 RPMs and check the voltage again. It should rise to 14 + volts.

Will do once I get the FPR swapped out and engine idles and rev's better.

Trying to get the excess fuel pressure under control first.

[Dave WM]

hard to say, obviously an OE would be best but maybe harder to source. I would go cheap, bosch if you can find one, but who knows prob all made in the same factory now. dont really think the life time stuff is worth it.

Edited March 31, 2019 by Dave WM

[mbz]

Just now, Dave WM said:

prob all made in the same factory now.

Fo' sho!

The lifetime warranty from O'Reily is tempting for $30 bux more.... how often do these FPRs fail?

[Dave WM]

2 minutes ago, mbz said:

Fo' sho!

The lifetime warranty from O'Reily is tempting for $30 bux more.... how often do these FPRs fail?

mine looks Orig, so 46 years so far.

just triple check the form, there are two types one with 3 outlets and one with 2 (later models IIRC).

[Dave WM]

I suspect the failure mode prob has to do with rust/dry rot of long term non use.