What would be the symptoms of a bad Fuel Pressure Regulator?

Sidicer

Hello everyone, after full head restoration and more expensive timing chain kit my car still overfueles and stutters.
Also backfires like a machine gun no matter at what RPMS gas was let off.

I think that it could be a bad Lambda (1st O2 Sensor), a bad Fuel pressure regulator or cucked injectors.
So I wonder how do our Z22SE Engines react to faulty/broken/stuck Fuel pressure regulators?

Thank you

IDI_AMIN

Is it possible that you never done the timing correctly?

How did it run before you done this work?

Sidicer

IDI AMIN said:
Is it possible that you never done the timing correctly?

How did it run before you done this work?

Got it with timing chain damage, got ir replaced badly at a shit shop (stripped gears, chain put on randomly, intake cam was rotated by two teeth out of timing), now I got the timing chain done correctly, at a good shop with way better parts. 80% of the problems I had are gone, the car finally drives like a car should.. But some problems still remain, like smoke when you slam gas, jerking/stuttering from time to time, loud backfire's and flames)

IDI_AMIN

Sidicer said:
smoke when you slam gas, jerking/stuttering from time to time, loud backfire's and flames)

I think smoke when you slam gas could be related to piston rings or valve stem seals. The colour of the smoke lets you know which it relates to.

But with a proper engine rebuild you should not have that problem.

Stuttering can be related to air leaks. timing could be done incorrectly, which could explain the backfiring.
Also it could be related to the ignition side like coil pack and spark plugs

If the fuel pressure regulator was broken/ or faulty, I don't think the car would start, As it needs fuel to run.

This is a method for testing functionality and also cleaning fuel injectors.

https://www.youtube.com/watch?v=rUUgR94drxg

Sidicer

IDI AMIN said:

But with a proper engine rebuild you should not have that problem.
Stuttering can be related to air leaks. timing could be done incorrectly, which could explain the backfiring.
Also it could be related to the ignition side like coil pack and spark plugs

I forgot to mention that my car doesn't have the secondary O2 sensor and ECU always reads "0mV Rich" every moment, from Idle to Redline. So I want to fix exhaust leaks before first o2 sensor and by a new secondary (4pin) O2 sensor and put it with a fake cat and then we'll see what happens.

Smoke only smells like unburnt fuel, no oil smell at all. Even if you redline it and then try to stutter it - it only pops and blackish/whiteish smoke comes out smelling like gasoline.

IDI_AMIN

https://www.motortakaful.com/en/blog-detail?blog-title=Blue,%20White,%20Grey%20And%20Black%20Smoke%20What%20Do%20They%20Mean

IDI_AMIN

https://carfromjapan.com/article/car-maintenance/black-smoke-from-exhaust/