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Discussion Starter #1
Hi,

I have had an issue with my 2006 Touareg V6 3.0 while starting the engine after 1/2 days stopped.

The issue regards big difficults when the engine is starting by taking at least ~7 seconds to be started. Sometimes it doesn't even start and it needs to trigger the starter once more.

It seems that there is no fuel reaching the engine so it could be possible to be started.

After 1 or 2 engine starters, it can be possible to be started and when it starts running, there is no white smoke exausting.

After the first start when the engine is running if I stop it, there is no more issues on the next starting attempts and it runs imediatly.

Is there any clue on what it could be?

Thanks in advanced.

Joao Silva

Regards.
 

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Perhaps the reason there has been no response is that we have no way of knowing where in the world you are located. There is nothing in your identifier to indicate country or area. From the English in the text I assume you are NOT in North America.
How close to a large city (and which one) are you? Are there any dealers you can turn to? What did they say is wrong? I could refer you to a good independent mechanic near me but I bet he is NOT near you!
 

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Finish filling out your info. Don't need your exact location. Just something to pin down the general area.

It can be many things.

A scan of the system with VCDS would be helpful.

First guess would be camshaft position sensors.

If the crank position sensor fails fully, you get no start. If the crank position sensor fails intermittent, you get intermittent no starts.

If the camshaft sensors fail, you can still start but it will be an extended, long start sequence.

Most replacement parts are fine by anyone, but both the crank and cam sensors have been troublesome with cheap off brands. I would recommend only trusted sources.

Of course, it could be other things also.
 

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Discussion Starter #5
Thank you for your replies.

Sorry, my fault by missing a brief presentation.

I am from Portugal near Lisbon city.

Replying to some questions already posted, I already went to some mechanic which weren't able to identify the possible root cause for this to be happening.

The car was already connected to a VCDS system without reporting any faulty code.

What was mentioned from two different mechanics was that the cause could be pointed to the fuel missing the cylinders due to the pump system issue(?) as this only occurs if the car is stopped for a long period (at least 1+ day).

This might not be related with weather temperatures as this occurs with cold and hot temp.

Thanks.
 

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TLDR: You need better mechanics.

I am still 90% sure you will find your issue around the cam or crank sensor. It is a common failure part(s) that cause starting issues in these vehicles.

You need someone who understands the electronic start sequence, the sensors, and the electrical system of modern vehicles. Any mechanic that is versed in this should be able to find the cause. It would be a plus if the mechanic has some VAG experience, but that is not mandatory.

Basically you are looking for a mechanic that specializes in electrical system repairs.

You need air, fuel, and spark to start. Now, if all we are getting is an extended start, then that makes me think that the computer is using a fail safe (backup) starting sequence.

The cam and crank sensors can cause this. So, that is one possibility that we need to look at. It is aggravating that the cam and crank sensors often do NOT set a code in the Touareg.

The other thing that is aggravating is that they fail intermittently. So, they work when cold, but don't want to do a warm start. Or, they work when warm, but don't want to do a cold start. Or, the work when they want to and don't when they don't want to. Most times it is temp related, but not always.

The mechanic needs to start by using VCDS to log log the sensor inputs. If we see clean signals, then we move on. If we don't get clean signals, then we start looking at the sensors first then the wiring second.

It can be aggravating since the mechanic will need to observe and log these sensors while the vehicle is operating normally and will also need to observed and log these sensors when the vehicle is acting up.

The last thing to point out is that these sensors tend to

Later, If the sensors look good, it would not hurt to do a fuel system pressure test. You unhook the fuel line and put in a pressure gauge. You check pressure from both pumps. Then you unhook the line and do a volume test. You run each pump and collect the fuel it pumps. Each of the two pumps needs to put out a certain amount in 30 seconds.

clubtouareg.com/forums/f43/3-2-v6-2004-crank-no-start-no-rpm-or-crank-speed

Failed G28 (Engine Speed Sensor) means engine will not start (period...would need new sensor), G40 (Engine Camshaft (intake) Sensor) will still allow engine to run. BUT a failed G40 or G163 (exhaust cam position sensor) will require many turn overs as the ECU calculates timing from the G28 on the flywheel and this means the engine has to turn over and over and over for the marker to pass over the sensor twice. Also the engine would run crappy because the timing I believe is retarded and will remain in this position to keep the timing such that it can be calculated.

See pages 45 and 50 of the attached.

https://www.clubtouareg.com/forums/attachment.php?attachmentid=176650&d=1493076501
Don't forget in that above quote you could have a sensor that only fails when doing a warm start, or when doing a cold start.
 

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Discussion Starter #7
Thanks for your precise explanation.

My mechanical knowledge and skills are not so good. I will try to look further on that and look for a electric experienced mechanic.

I was just wondering if a crank sensor could lead for a long cranking often randomly instead of only when the engine is cold.

On my Touareg it happens quiet often if the car is stopped for a 2+ days.

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Yes, it can be a random problem, at first. It usually gets worse. Eventually it will lead to a total no start.

Most common is consistent failure of a hot restart.

Next common is random failure of cold restart.

Lest common is random failure of starts period. Hot or cold does not matter.

I can not guarantee that it is a sensor. However, the chances are high and the sensors need to be checked.
 

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Discussion Starter #9
This starting issue never happens when the motor was recently started.

Thanks for your help and guidance. I will try to find for a experienced mechanical and look the mentioned points.

Regards.
 

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Cold start

Hi,
I’m new to this site and not sure how to create my own chat,I hope you don’t mind that I jumped in on this one but I have roughly the same problem and haven’t got the foggiest what the issue is.
First thing in the morning my Touareg v6 3l tdi 56plate
Will crank over for 10-15secs then a huge cloud of blueish smoke with a strong smell of diesel.
I’ve had a full service on it less than 6 months ago, brand new batterie 2 months ago, new glow plugs, new fuel pump relays had it diagnosed but no faults.
But the problem still arises.
I hope somebody can help
Thanks
Dave
 

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Hi,

I have had an issue with my 2006 Touareg V6 3.0 while starting the engine after 1/2 days stopped.
The issue regards big difficults when the engine is starting by taking at least ~7 seconds to be started. Sometimes it doesn't even start and it needs to trigger the starter once more.

It seems that there is no fuel reaching the engine so it could be possible to be started.

After 1 or 2 engine starters, it can be possible to be started and when it starts running, there is no white smoke exausting.

After the first start when the engine is running if I stop it, there is no more issues on the next starting attempts and it runs imediatly.

Is there any clue on what it could be?

Thanks in advanced.

Joao Silva

Regards.

I had a similar issue that I posted about a year ago and never really found a good answer.

When I originally purchased my Treg I put it in storage for over a year and would go out to start it every once in a while, maybe every 2-4 wks. It would always crank for several seconds and sometimes I would have to stop cranking and try restarting and would eventually start. I believe it had to do with the vehicle sitting for so long and the fuel flowing back to the tank. I could always hear the fuel pump running as soon as I open the door, so I knew the pump was working.

Fast forward two years and now I drive it almost every day and do not have these issues anymore. I also use Lucas fuel injector cleaner every other tank, so I think that helps too. It could have been dirty injectors. Not really sure, but starts fine now.
It still runs rough for a few seconds every morning when I pull out of the garage and then clears up as soon as I drive away.
 

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Discussion Starter #13
Thanks for your response.

I have beed visiting some mechanical garages and got several feedback different opinions.

The most recent ones regards the fuel feed/return pipes and also the fuel filter holder.

Maybe I will look into this as it is not an expensive part.

Thanks.
 
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