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Vauxhall Astra 1.7 CDTi Z17DTL - Fuel rail pressure fault (waveforms) - Fixed #

Posted by Mark Robins on September 6, 2011, 5:16 pm

Year of Manufacture *: 2003
Engine Size and Code *: 1700.cc Z17DTL
( Optional ) Scanner Used: Autocom
( Optional) Fault Codes: Low rail pressure

Hi Chaps

Have this vehicle with rail pressure problem
Rail pressure low at cranking (won’t start), tow start engine idles OK, but cuts out under high loads.
Leak-back tested injectors (OK)
Carry out hydraulic integrity test. Disconnected crank sensor, cam sensor and IMV, cranked engine still low pressure: 700mv at pressure sensor.
Tried separate fuel supply.

New pump complete with new IMV and priming pump fitted same results!
No external leaks.
Is there any kind of pressure relief valve fitted to the rail?

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 6:40 pm, in reply to "Vauxhall Astra CDTI Fuel pressure blues"
Mark Carter

Hi Mark,

Two questions;

1) What system is fitted to the vehicle?

2) Exactly how did you carry out the high pressure test on the pump?

Regards Mark

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 7:28 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"

Hi Mark,

The fuel system is Bosch EDC 15 C7 Common rail. IMV control no pressure reg.

I carried out the pressure test using the non-intrusive "Frank Massey method"
Take out all fuel consumers i.e. the injectors by disconnecting the cam and crank sensors and then the injectors for good measure.
Disconnect the IMV this defaults to full flow hence pressure, crank engine and scope fuel pressure sensor voltage (it got up to 700mv). It should go to max pressure 4v+

Mark Robins

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 8:21 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Robins

Hmmm, just been reading my Common rail diagnostics notes from James Dillon's course; and it turns out there is a pressure release valve in the rail set to 1500 bar on some systems, so my next task is to remove the rail. Will report my findings.

Mark.

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 9:19 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"

Two things;

1) are you sure the IMV works as you think on that model? (there are two types of Bosch IMV, standard and special)

2) are you sure that the system is not duel point control?

The pressure limiter is easy to check, just remove the return pipe and see if there is any flow present.

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 10:11 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"

Hi Mark,
First I didn't know there were two types, but when I remove the connector to the IMV with the engine idling the fuel pressure momentarily rises before the engine cut's out. If you mean by dual point that it has both pressure regulation and inlet volume control then I am sure that it has only IMV control. The rail is pretty difficult to see on this model (tucked right at the back of the engine) but the pressure regulator is big enough to see if it was there, also my wiring diagram shows no pressure regulator fitted. I also checked a known good car (owned by one of my mechs) and the duty cycle falls in-line with what I scoped; the less "on time" the higher the pressure. I cant see no return pipe although had a quick look on Ebay and the pictures for this model does seem to have one.

Thanks for the input will post my findings when I have removed the rail.

Mark Robins

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 6, 2011, 11:24 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Carter

Fair play, you should be able to test the limiting valve without removing the rail.

The pipe from the rail should feed into the normal return line.

Have you got the Delphi sealed rail kit?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by dave harney <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on September 7, 2011, 8:30 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"

Hope this is useful
Regards
Dave

You can trim a sheeps wool many times, but you can only fleece it once !

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by dave harney <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT2603' width='330' height='300' border=0 style='border:none;'> on September 7, 2011, 8:36 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Dave Harney

and.......

You can trim a sheeps wool many times, but you can only fleece it once !

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on September 7, 2011, 8:46 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Robins

Thanks Dave, cant see any over-pressure relief valve on the rail in those diagrams hmmmm. and Mark, no I don't have the closed rail kit unfortunately.

Cheers gent's

Mark Robins.

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 7, 2011, 1:29 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"

The fuel limiting valve is screwed in the end of the rail and may not be shown in the schematic.

With all due respect, you have checked the supply line and the pumps ability to draw fuel?

Mark

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1448' width='330' height='300' border=0 style='border:none;'> on September 8, 2011, 7:44 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Robins

Yes, checked with seperate supply, also new high pressure pump came with new priming pump (mechanical). Correct me if I'm wrong but doesn't the limiting valve only come into play with a sudden loss of pressure i.e. cracking open an injector pipe?

Cheers,

Mark Robins.

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 8, 2011, 9:32 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Carter

You have mail

Modern cars, Its all wizardry and witchcraft

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Ed Kaps <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT5536' width='330' height='300' border=0 style='border:none;'> on September 8, 2011, 6:10 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Edward Kaps

Yes Mark(R)
You are quite right, flow limiting valves are an available option from Bosch to the VMs for fitting in the injector pipe to shut off fuel in the event of a sudden increase in flow through them.Quite expensive,so most don't bother, relying instead on 'dual point control' or single point with a pressure relief valve in the rail, as Mark(C) mentions,you would be aware of that leaking from the pipe.
Ed Kaps

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Robins on September 9, 2011, 7:59 am, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Message modified by board administrator September 16, 2011, 9:15 am

Thanks guy's for the info, We're presently just finishing replacing the cyl head on a Vauxhall Vivaro 1.9 CDTI, this gave me the chance to examine the rail, and sure enough this is single point control and has the relief valve and pipe fitted so I'm got some confidence that this may be the problem on the Astra, hopefully we will be getting it back in today and get the rail off.

Keep you informed.

P.S. Mark C have not received any e-mail so far.

Mark Robins.

Re: Vauxhall Astra CDTI Fuel pressure blues

Posted by Mark Carter <iframe src='https://members.boardhost.com/ukautotalk8/info/user=UKAT1428' width='330' height='300' border=0 style='border:none;'> on September 9, 2011, 12:48 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Mark Carter

Sorry, I meant PM

Mark

Modern cars, Its all wizardry and witchcraft

Fixed #

Posted by Mark Robins on September 14, 2011, 11:01 pm, in reply to "Re: Vauxhall Astra CDTI Fuel pressure blues"
Message modified by board administrator September 16, 2011, 9:15 am

Hi Gent's
Finally removed the rail and sure enough there's a relief valve fitted with a pipe connected to the return.
customer supplied a second hand rail

which we fitted and rail pressure is back to normal.

Thanks again for all the input/info, hope my experience's with this will help somebody else.

Mark Robins.

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