Long cranking

[RichLV]

Isn't there a check valve at the pump end of the system designed to keep pressure on after shut down? That would cause a leak down too if it was leaking or missing.

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Its a part of the pump then, since I couldn't find it as a separate part.

Check if injector's are good

I think if they would be bad, I'd feel it when driving it. It wouldn't run as good as it does. Only the long crank is the issue.

[UrS4boy]

Anatomy of two 091G (OE) style fuel pumps (VDO and Bosch)

Isn't there a check valve at the pump end of the system designed to keep pressure on after shut down? That would cause a leak down too if it was leaking or missing.

Correct.

Anatomy of two 091G (OE) style fuel pumps (VDO and Bosch):

http://forums.quattroworld.com/s4s6/msgs/179948.phtml

[Majorcina]

Check if injector's are good

[Kieron20V]

Isn't there a check valve at the pump end of the system designed to keep pressure on after shut down? That would cause a leak down too if it was leaking or missing.

Sent from my Nexus 6P using Tapatalk

[RichLV]

If you take off the case for fuel pump relay, you can manually turn it on, so before you start it, get some pressure up, and see if that helps the start, if so, you found your problem.

Stuck open injector would cause blue smoke on start up

Thanks, good thought. I'll give it a try.

[hunker7]

Black

Mine was blue

[UrS4boy]

Stuck open injector would cause blue smoke on start up

Black

[hunker7]

Since the FPR isn't expensive, maybe just get a new one altogether? Because it sure sounds like the rail pressure drops after standing. Or it's an injector stuck open, but in that case I would get a lambda correction code.

If you take off the case for fuel pump relay, you can manually turn it on, so before you start it, get some pressure up, and see if that helps the start, if so, you found your problem.

Stuck open injector would cause blue smoke on start up

[RichLV]

Since the FPR isn't expensive, maybe just get a new one altogether? Because it sure sounds like the rail pressure drops after standing. Or it's an injector stuck open, but in that case I would get a lambda correction code.

[hunker7]

When you crank, and it wants to start, but doesn't. Don't know how to call it in other words.

Oh I know what you mean, mine does that too. When it does start the first time, it's usually when she's cold, when she warms up, she takes a while to come to life.

[RichLV]

What do you mean by bubbles?

When you crank, and it wants to start, but doesn't. Don't know how to call it in other words.

[hunker7]

What do you mean by bubbles?

[RichLV]

Mine does the same. Sometimes it'll start on half a turn, sometimes it takes two three or more to get her started. My pressure regulator is pretty new, and I get the same problem. Also, I would expect it to not run correctly if FPR isn't doing it's job properly.

It was doing it randomly some time ago, but now after a night of standing I have to crank it fairly long in the morning. And it bubbles too.

[hunker7]

Mine does the same. Sometimes it'll start on half a turn, sometimes it takes two three or more to get her started. My pressure regulator is pretty new, and I get the same problem. Also, I would expect it to not run correctly if FPR isn't doing it's job properly.

[RichLV]

Hey folks.

I've recently assembled my precious and have run into strange starting issues. After being shut down for some time, it takes pretty long time to crank the car before it starts. Also while cranking it bubbles a bit and after that starts and runs without any issue. I have a strong impression that it's the Fuel Pressure regulator, because once started, I can shut it down and start it again with half turn of the key. Seems like it doesn't hold the pressure in the fuel rail after shut down. No other issues have surfaced, it runs fine on boost, no misfires, no erratic running whatsoever.

Thing is, I've changed the fuel rail during the rebuild, since mine had the mountings cut off for some reason. I haven't hooked up the fuel pressure gauge yet, don't have any available right now.

I'm thinking maybe get a new regulator altogether. I have two choices:
1)Bosch 0 280 160 575
2)Pieburg 7.22017.50.0
They aren't too expensive. The Bosch one costs marginally more.

Engine - AAN.

Any advice appreciated.