Touareg 3.0 v6tdi wont start

[silverado25001]

Hello everyone , this is my first post and am hoping for some expert help. I have a 06 touareg 3.0 tdi and after changing the fuel filter the car started and ran for about 5 seconds and i havent been able to get it to go since .
I did prime the filter canister with vcds and have been attempting many techniques to remove what I hope is an airlock for the last 7 days .
I understand that common rail diesels are supposed to self bleed , but I have cranked this thing for ever with no luck.
Are there any expert diesel mechanics who can advice me on a method that works to remove air from this particular fuel system , I am at the end of the road and worried that I may have a HPFP failure .
Thankyou to anyone who can help.

Regards Silverado25001

[Umai Naa!!]

These have two electric pumps, if I'm not mistaken. One in the engine bay on the passenger's side of the firewall, and the other is obviously in the tank.

Might be worth testing these to see if they work. The fuses for them are in the plenum at the base of the left side of the front windscreen. It'll be fuses 13 and 14, from memory.

Also check the live data with VCDS, and see if you can pull up an engine speed reading while cranking. Must be above 280rpm to fire up. If it's below 280rpm, check battery voltage while cranking. Could be on it's way out. If you can't get a reading at all, look at G28 engine speed sensor. Have seen a few of these die, and not throw codes.

[silverado25001]

Thanks Umai Naa!! have checked fuses and relays in plenum , I have limited my cranking to fully charged batteries , will check live data for cranking speed . Yep the weird thing is I am not getting any codes. So if G28 has failed will that cause ecu not to signal injectors to fire ?
Thankyou for some new information.
Regards Silverado25001

[Umai Naa!!]

Yeah, pretty much. If the ECU doesn't know what the crankshaft is doing, it won't fire the injectors.

[silverado25001]

Yeah, pretty much. If the ECU doesn't know what the crankshaft is doing, it won't fire the injectors.

Thanks mate will have a look at G28

[Transporter]

Hello everyone , this is my first post and am hoping for some expert help. I have a 06 touareg 3.0 tdi and after changing the fuel filter the car started and ran for about 5 seconds and i havent been able to get it to go since .
I did prime the filter canister with vcds and have been attempting many techniques to remove what I hope is an airlock for the last 7 days .
I understand that common rail diesels are supposed to self bleed , but I have cranked this thing for ever with no luck.
Are there any expert diesel mechanics who can advice me on a method that works to remove air from this particular fuel system , I am at the end of the road and worried that I may have a HPFP failure .
Thankyou to anyone who can help.

Regards Silverado25001

Make sure that the filter canister is sealing and it's not sucking the air in. It's rare that the component would die just at the moment you're changing the fuel filter, don't you think? But, then again I don't know what else have you done to your Touareg. Some maintenance tasks are better left to the mechanics. The under the bonnet of the V6 Touareg, should be the indicator of it. :)

[Jmac]

That 100% sounds like air. Air and diesel , don't mix if you have done the VCDS prime I suggest you do it several times, even with Golfs especially with the Bluemotion it takes atleast 2 ECU primes. If you have done that then it must like Transporter suggest be getting air in. It was ok before the fuel filter was changed therefore introduced fault
Good luck

[silverado25001]

Thanks jmac , do you have any ideas how to purge air from the system , I have had feed and return lines off trying and probably introduced more air .
Regards Silverado25001

[Umai Naa!!]

System closed, and prime it through VCDS.

It'll just cycle the fuel through the lines and back to the tank.

[silverado25001]

System closed, and prime it through VCDS.

It'll just cycle the fuel through the lines and back to the tank.

Thanks mate I am going to try exactly that .

Best regards

Silverado25001

[Transporter]

Circled in red is the bleeding screw. Turn the ignition on for 3-5 second then off, open the bleeding screw let the air escape and close it, repeat several times. The engine should start now, unless the Orings at the filter canister don't seal.

http://www.vwwatercooled.com.au/forums/images/imported/2014/03/7uvuvupa-1.jpg

Sent from my GT-I9505

[silverado25001]

Thanks transporter, I was under the impression that screw was there to gain access to the bottom of the canister for syringing out water , however I did try using it as a bleed but can't get any air to flow from it . Did you mean ign on for 3-5 secs and open screw at same time to bleed any air then off and close screw and repeat.

[Transporter]

You can try that, but as long as you filled up the filter canister with the diesel and there is no air leak anywhere, turning the ignition on and off few times should be all that's needed to start the engine.

Did you use new Orings?

[Snail Style]

Crack the injector lines off at the injectors one by one until fuel is clearly coming out. Usually once you have done a few of them the vehicle will start and self-bleed itself. That screw is as you said, a water trap screw.

The other way to do it is to run the program through with a scan tool.

If you were in Melbourne I'd be happy to give you a hand, but your not so good luck. :)

[silverado25001]

Crack the injector lines off at the injectors one by one until fuel is clearly coming out. Usually once you have done a few of them the vehicle will start and self-bleed itself. That screw is as you said, a water trap screw.

The other way to do it is to run the program through with a scan tool.

If you were in Melbourne I'd be happy to give you a hand, but your not so good luck. :)

Thanks Snail Style do you mean crack them and crank engine until fuel comes out , because I tried that and ran electric pumps and cant get any flow .

[Umai Naa!!]

Do not crack the lines on a common rail diesel.

Big no-no.

[Snail Style]

Theres no problem doing that, I've done it many times. The fuel lines do not need to be replaced once loosened anymore. The other possibility is your high pressure pump has killed itself, it was abit of a common thing for them to fail.

Really needs to get to a mechanic so they can ensure it's been bled correctly and start testing fuel pressures ect.

[Umai Naa!!]

High rail pressure is the reason why you dont crack the lines on a CR diesel.

[MHAuto]

Theres no problem doing that, I've done it many times. The fuel lines do not need to be replaced once loosened anymore. The other possibility is your high pressure pump has killed itself, it was abit of a common thing for them to fail.

Really needs to get to a mechanic so they can ensure it's been bled correctly and start testing fuel pressures ect.

Are you seriously telling him to crack open high pressure lines on common rail system? Are you trying to kill someone? Do you know what type of pressure your dealing with?

What are your qualifications to give this type of advice?
Send it to a proffesional before someone gets hurt or killed!!

[Transporter]

agree, the pressure in the CR injector fuel line can cut your finger of or even worst.

It can easily happen that spray out from the line could pierce your skin. Here is something that the DIYs don't discuss in the forums;
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2532970/

In my early days at work (early 80s), my workmate was testing the diesel injector that had an opening pressure of 160bar (fraction of today's CR injector), one of the 5 holes at the injector tip was not spraying well, so he touched it with his finger. The stream pierced deeply his finger, he ended up in surgery and was out of work for more than 2weeks.

[Snail Style]

I've seen the photos, and heard all the stories. But a line which is cracked prior to starting up will not come spraying out with 1600bar of pressure. The rail aims to hold 300bar of pressure at idle and cranking via the fuel regulation valve n276 on the end of the rail. If the injector is cracked prior to cranking(ie. to bleed the system) a trickle of fuel will come out whilst cranking, or most likely air bubbles in his case. The amount of fuel in the rail is not all that much, so the slightlest leak will drop that pressure right off.

I'm no expert but it's always worked for me in my day-to-day. I did also mention it really needs to get to a mechanic so it can be tested properly. :P Internet diagnosis seems to have failed to this point.

[99_FGT]

I note there is an if there. If the injector is cracked.
I'm glad I don't work with you...

[Jmac]

I've seen the photos, and heard all the stories. But a line which is cracked prior to starting up will not come spraying out with 1600bar of pressure. The rail aims to hold 300bar of pressure at idle and cranking via the fuel regulation valve n276 on the end of the rail. If the injector is cracked prior to cranking(ie. to bleed the system) a trickle of fuel will come out whilst cranking, or most likely air bubbles in his case. The amount of fuel in the rail is not all that much, so the slightlest leak will drop that pressure right off.

I'm no expert but it's always worked for me in my day-to-day. I did also mention it really needs to get to a mechanic so it can be tested properly. :P Internet diagnosis seems to have failed to this point.

Mate, cant agree more, that's why I don't post so much now, too many experts and you are right someone will get hurt or worse, I been around it for moons and cant stress enough how careful you have to be. The fault has been introduced here , it was fine before the filter, so really needs to be bled and tested properly, not poking and hoping.
To the OP hope you get a successful result.
Cheers
Jmac

[Transporter]

+1
also, it would be good to know where the OP bought that fuel filter, is the genuine VAG from the dealer or Genuine ebay?

[silverado25001]

+1
also, it would be good to know where the OP bought that fuel filter, is the genuine VAG from the dealer or Genuine ebay?
For your information the filter was a genuine vag part from the local dealer.

[Transporter]

For your information the filter was a genuine vag part from the local dealer.

So, I take it, as it still refuses to start. :(

[silverado25001]

Yep no start , have removed the HPFP and taken it to some diesel injection specialists to be tested . Haven't had a diagnosis from them yet.

[Jmac]

Oh dear as far as that. As it was fine before the service, seriously would have been running the lift pump either via ECU, or power up probe or worst case low pressure air line in fuel tank to push up the fuel. You get air in it you chase the tail.
Jmac

[The One]

Oh dear as far as that. As it was fine before the service, seriously would have been running the lift pump either via ECU, or power up probe or worst case low pressure air line in fuel tank to push up the fuel. You get air in it you chase the tail.
Jmac

Exactly. Like everyone keeps saying it needs to be bled!

[silverado25001]

To everyone who has posted their advice and ideas I thank you all for the encouragement. Well I finally got the engine running yesterday afternoon after reinstalling the HPFP.
The strange thing here is that when I cranked the engine in the past to try to bleed the return line from the HPFP with electric pumps running all I ever got from the pump was a trickle , this time I observed a good flow in my clear hose with lots of air apparent. Replaced return line to filter after purging most of the air , ran both elect pumps via a relay bypass for about 5 minutes ( The same way I have done previously ), replaced relays and proceeded to crank engine .
After 4 cranks of about 10 second duration with no warning engine started and ran smoothly. ( Felt like winning the lottery ).
So after reinstalling the HPFP the bleeding process was simple and as described by many, so having the HPFP tested by the diesel injection specialists seems to have cleared some kind of blockage or other problem with the pump.
So it was air in the system as expected and I can confirm the engine will self bleed and return air back to the tank if elect and HPFP pumps are working correctly.

Silverado25001

[Transporter]

That's a good result.
Lets do it again. :grin:

Just kidding of course. :)