fuel pressure regulator

[George]

Checking earth continuity and I have nothing for the fuel pressure regulator. Is this correct or should I start stripping the loom

[George]

Anyone? Im really lost with it. I have 5v at the rail sensor. Thamks

[cully]

the FPR is bolted to the pump which is bolted to the block which should be earthed via the gearbox-chassis-battery negative terminal

[pro_steve]

The fuel pressure regualtor uses a pulse width modulated wave so you won't be able to see much except check the live. The earth is what is modulated through the pin on the ECU as in this diagram. This helped a guy with a similar problem not long ago, turned out the relay was faulty IIRC.

http://www.hdi-tuning.co.uk/downloads/edc15c2pinout.jpg

[George]

That checks out ok then. Guess thats another 306 going to car haven.

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Cheers but im absolutely lost when I look at diagrams like that

[pro_steve]

Why don't you try another FPR (or give it a proper clean)?

What is your problem?

Is the lift pump priming when you turn the ignition to two clicks?

[George]

Have put another for in. Lift pump primes engine turns over but won't fire. Drove 40miles fine next day it struggled to start when to shop and from then on it won't start. Brand new fully charged battery, 7v at injectors with ignition on, 5v at frps with ignition on.

[pro_steve]

There's also a setting where you need 120 bar at the fuel pressure sensor to fire the injectors.
If you're not getting enough fuel pressure it can be the pump (quite likely), regulator (very likely, but you've changed that), or the fuel pressure sensor (I've not seen many of these go wrong).

Can you attach a volt meter to the output pin and ground pin of the fuel pressure sensor whilst cranking? Through a rough calculation you should see about 0.36 volts?

Or easier connect PP2000 and log the pressure whilst cranking. Where are you based, I'm in Bristol if you need any help.

[Poodle]

I thought it needed closer to 280bar to fire the injectors on start-up..? Also, injectors have been known to cause fuel pressure issues, although thats probably about as common as the frps failing.

[George]

Im near hull so a fair way away. I will have a look tomorrow. Someone said clamp fuel return line. I tried this and it just sprayed fuel from the leak off pipes

[Poodle]

I should think they meant the fpr return line off the pump.

[George]

Ahhhh ok I'll try that

[pro_steve]

Poodle, 280 bar is the idle fuel pressure setting so that's what you'll see with the engine stopped but ignition on. For the ECU to send a pulse to open the injector though you need a minimum of 120 bar at the fuel rail. The injectors can cause fuel pressure to drop, but only usually at full load, I think this is because the seals kind of give way and the fuel pressure drops really suddenly.

[Poodle]

Ah fairy snuff, cheers. Somethings gone amiss in that first sentence, fairly certain you won't see 280bat with engine off.

New injectors solved my cutting out issues btw, I just didn't realise at the time thanks to my enthusiastic attacks on roundabouts.