What’s this hose for

magpies79

Yeah that’s pretty much how mine sounds but I’d say worse and a lot more higher in rev sound would if this part was to fail would it effect it while driving to because you can almost hear it still when driving like hunting?

I’ll try have a look at that pipe when she gets back but it’s dark by the time she gets back so might be tricky to see.

i have looked at a new SCV lowest price I can find is £210 for genuine one as a lot have mentioned putting on a cheap one ends up failing a few months later.

Goudy

It'll run rough throughout it's range.
You'll get poor mpg, low power and poor acceleration.
It's just at idle, you'll notice more the rpms hunt.

I seem to think from 2010 it's a Denso fuel system.
If it is the one I think you can turn it 180 degree and see if it runs better before buying one.

If you can find the Denso part number or even the VX/Opel part number, try searching that rather than just for the part/car.

I think this engine and fuel system went in a lot of different GM cars, like Chevrolet's  



 

magpies79

Yeah might give that a go see how it goes is it just secured by 2 bolts think it’s to the bad of engine on the side isn’t it 

https://vauxhallpartsdirect.co.uk/product/vauxhall-astra-2010-2015-fuel-pressure-regulator/

I’ve emailed them to double check 

is it possible to run the car without it plugged in and to see if there’s no hunting on idle which you’d think would mean it’s definitely the SCV

tedted

they are not easy to get at and normally do them from underneath.\you should get it on a scanner and look at live data

magpies79

Yeah need to get one I’ve only a basic one my mate has a opcom one but he’s away
is the SCV valve at bottom or top at the back i thought it was at the top on the side but starting to doubt that now your saying best to go underneath lol

Goudy

magpies79 said:

https://vauxhallpartsdirect.co.uk/product/vauxhall-astra-2010-2015-fuel-pressure-regulator/

It's a Denso valve.
VX Part numbers 55582723, 98114309 and 98114311
Opel part numbers 819143, 819173
Denso part number is 294200-0460

It was also fitted to a Mazda RFY313SM0, RFY313SM0A
And Isuzu 8981143090.

I'm not sure unplugging SCV is going to give a definitive result.
It's either going to be closed or open once unplugged, so at best there's a 50% chance it's going to be wrong or right, though I would gather the value operates in between fully open and fully closed.

You could do with knowing what the rail pressure should be at idle, then scanning the rail pressure to see what is actually is. This will tell you if the rail pressure is off.
I'm not too up to speed with later gen common rails, but I would think around 3000psi (20,000+ kpa) or so at idle to around 20,000 psi or more(138,000+ kpa) under high load, but don't take my word for that, check.

But there's more to just this valve that could cause an issue like this with rail pressure (if that's what it is)
It could be drawing in air into the fuel system somewhere, that will cause the rpms to bounce and hunt.
Have you done anything just before the problem arose, like change the fuel filter?
That's usually the first point of call when it comes to air leaking into the fuel system. 

A duff or weak injector would also cause a similar issue.
It would stutter and hunt, be down on power and that injector is spilling off too much fuel, reducing the rail pressure.
You'd need a leak off test which measures what each injector is returning. The very least they should all be returning an even amount between them.

There's also a rail pressure relief valve at the end of the rail, if that is crudded up, it might leak off pressure back to the pump, but you'd get a low pressure at crank it is would be difficult to start.


If you are going to try and turn the SCV,( it's free and reasonable place to start knowing they fail) I believe the hp pump is between the engine and firewall and is tricky to access.
Some manage from above, some from below.
It's on the back of the pump so one screw is up above the valve and the other below the valve, hence the above and below.

There are only two socket cap (allen) bolts holding it in, so you might have some luck from above with an allen socket on a 3/8 or 1/4 inch ratchet with an extension bar. 
A magnet might help in case you drop the bolts.

magpies79

Yeah never had any issues on start up has always started first time and had the issue with this car for a long time but was only every slightly surging sometimes hardly noticeable.

yeah I’m going try with the SVC first take it off and turn it 180 as well it cost nothing and take it from there could do with a good code reader myself but seems a lot of the good ones can get a little pricey.

Goudy

magpies79 said:

yeah I’m going try with the SVC first take it off and turn it 180 as well it cost nothing and take it from there 

Just bare in mind that this isn't a definitive test.
The engine may still hunt and bounce if you turn the valve and it's totally knackered.

Just going off what I've read, these SCV's do tend to get worse over time before they appear to fail completely at some point. The turning trick might not make a difference if it's the valve or not.


As for code reading and data logging.
In the past I've bought expensive software packages that are manufacturer specific, various leads and connectors and they are all stored on a cupboard with various old laptops.

These days I manage to get by with a full (paid) version of the Torque Pro app and a smartphone.
I've also helped a few owners out with Toyota Hybrids and find Dr. Prius fairly useful (ish).
They only cost a few quid but you need to find a suitable ODB2 dongle for them to work, again often only a few quid.

Problem most face is once to have access to the data, it's knowing what it all means.
The obvious could be staring you in the face but if you don't know, you don't know!

magpies79

Sorry been a busy one and not had time to get round to it yet I was able to speak with my sister in-laws friend his dad is a mechanic he said I could pop it round on Tuesday and he will hook it up and see what faults its showing hopefully shed some more light on it 

magpies79

So had it hook up to a computer today and these are the only fault codes showing so feel like this doesn’t really help me much with regards to the surging and erratic rev counter 

top 2 codes I think are on there from when I started the car without the maf sensor plug in as they are coming up as history faults so faults that are no longer there?

the bottom one is glow plugs but he said unless the car is having trouble starting can’t see that being the issue unless maybe all glow plugs are on the way out and said that could cause problems.

car starts first time always has in the 5 years I’ve had it