Car refuses to start after piston replacement

I think there's 2 fuel pumps

snowwy66 said:

I think there's 2 fuel pumps

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Yep, the first one in the tank is low fuel pressure pump. It delivers the fuel to the high pressure pump that is on the engine and is driven by the intake camshaft. It seems to be working fine and it is delivering fuel. When plugged on OBD it shows pressure of around 550 psi. In the manual it says anything over 300 is good. So thinking that the second "high pressure pump" is faulty I replaced it. But, still the same fault code.
Thanks for your reply

If the primary fuel pump isn't working. The secondary pump will also struggle.

snowwy66 said:

If the primary fuel pump isn't working. The secondary pump will also struggle.

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It is working, delivering fuel. Before doing the pistons replacement the car started fine every time even though it had low compression on cylinder 1 and was misfiring.

Low fuel rail could be an injector stuck open.

andrevskig said:

It is working, delivering fuel. Before doing the pistons replacement the car started fine every time even though it had low compression on cylinder 1 and was misfiring.

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It may be delivering fuel. But is it enough fuel?

What's the primary pressure reading?

Is fuel getting into the cylinders if you pull out a plug or two? Is any one of them exceptionally wet (#1)?

snowwy66 said:

It may be delivering fuel. But is it enough fuel?

What's the primary pressure reading?

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550 psi according to OBD which is whiting specs according to the manual. Anything over 300 is good

jblackburn said:

Is fuel getting into the cylinders if you pull out a plug or two? Is any one of them exceptionally wet (#1)?

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None of them looked too wet

Did you plug in the rail pressure sensor?

JSM1284 said:

Did you plug in the rail pressure sensor?

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Yes. I even unplugged it to check what happens and got a warning on the dash straight away. I'm about to replace the sensor anyway tomorrow just in case that is the problem. Also checked the camshaft and it is fine. Even replaced the camshaft follower for the high pressure pump just in case. But it is all the same.
Now I'm thinking maybe the timing needs to be reprogrammed through the ECM. Clutching at straws here I know, but who knows anything is possible with later model cars. Engine is turning over fine and I'm fairly positive I set the timing chain right. Even got hold of the full factory manual(all 13500 pages of it, pdf) and still can't figure out what I'm missing. I'm no expert by any means, just a weekend mechanic, but it never crossed my mind that I will have this problem when I put the engine together.

An engine needs three things: fuel, spark, and compression. You can usually dribble fuel into the intake to check that. Spark may be a bit tricky - perhaps leave the coils and plugs on top of the engine while cranking - but you need to way to ground the plugs. A compression test isn't that hard, and a quick way to verify valve timing.

I know it's been a while, but anyone reading this, it was the front Fuel feed pipe. The check valve was stuck.
She runs happy now