[Aturek]

I have a 2005 V6 that struggles to start whenever temps get cold. Last winter it was only when temps got to around the zero mark but tonight when temps got to 35 degrees (for the first time this fall season), the Treg wouldn't start unless I gave it gas as I cranked it over. If I let off the gas after it started, the RMPS dip and it kills. Once I am able to get it into drive and zip around a mile, the engine warms up and it starts and idles as normal.

Has anyone experienced this or know where to start?! any help appreciated. Hoping to get time to scan for codes tomorrow or Monday.

 

[Gnits]

If it's a TDI, then there could be problems with your glow plugs, and if it's a gasser, then with the spark plugs or coils. Your EGR valve also could have gotten stuck open, which could choke out the engine at idle. Did you read fault codes? If you didn't yet, do so now.

 

[Aturek]

Here are the fault codes:
16485 - Mass Airflow sensor
16452 - Throttle position correlation
17819 - Secondary air injection system, Bank 2: insufficient flow
16395 - Camshaft A (intake) Retard set point not reached.

Any thoughts?

 

[Gnits]

You obviously have a problem with your MAF sensor. The insufficient flow code and some of the other faults could be also the result of that, because some of these are calculated/adjusted based on the MAF sensor data.

I'd check the MAF sensor and its wiring. Live data monitoring should enable you to identify a definitely bad MAF sensor, which then you'd need to replace. Then check whether there are any codes remaining. If you're already at it would be also worth checking the intake path for leaks and the working of the throttle body.

The last code could indicate a timing problem, but let's see first what the previous suggestions are bringing, and whether they make the codes disappear.

 

[johnk]

While not necessarily the hard start issuer, I'd worry about the cam retard code. My 04 had that and was failed cam chain tensioner. I caught it just in time.

 

[WolverineFW]

Also...you can get MAF sensor cleaner at any auto parts store....the OP may want to try that before anything else.

You obviously have a problem with your MAF sensor. The insufficient flow code and some of the other faults could be also the result of that, because some of these are calculated/adjusted based on the MAF sensor data.

I'd check the MAF sensor and its wiring. Live data monitoring should enable you to identify a definitely bad MAF sensor, which then you'd need to replace. Then check whether there are any codes remaining. If you're already at it would be also worth checking the intake path for leaks and the working of the throttle body.

The last code could indicate a timing problem, but let's see first what the previous suggestions are bringing, and whether they make the codes disappear.

Sent from my SM-G965W using Tapatalk

 

[Gnits]

Also...you can get MAF sensor cleaner at any auto parts store....the OP may want to try that before anything else.

Those do not ever work on the modern hot film sensors, like those used in Touaregs. Actually, they can't even touch the actual sensor film to begin with, because that's hidden deep in the plastic housing. One can try, but I wouldn't put much hope into that working even if the sensor has been confirmed being the culprit.

 

[Aturek]

While not necessarily the hard start issuer, I'd worry about the cam retard code. My 04 had that and was failed cam chain tensioner. I caught it just in time.

How was it fixing that? invasive and expensive?

 

[redbarron55]

Cam chain drive bits are on the rear of the engine and most require expensive engine removal to get to.
I wonder if this is correct and how much it cost to do.
If I were to gain access to the cam chains then I would be tempted to change all of the associated parts at one time.

 

[johnk]

How was it fixing that? invasive and expensive?

On 4.2 V8 engine doesn't have to come out. Bank 1 tensioner is at rear. Someone did it without removing timing belt and cams, but my tech pulled cams. V6 may be different. Cost was around $1300.

 

[Aturek]

Well, I changed the Mass Air Flow Sensor and nothing has changed other than the check engine light went off. However, it still didn’t want to start tonight unless I encouraged it with the gas pedal.

any other ideas??

 

[mpls]

Can you please tell us what engine you have? That will be helpful.

 

[gazaflash]

Could be the cold start valve. (If its a gas). This valve is only used when cold. Introduces an additional circuit to fuel the engine. When the engine warms up, the valve is switched off.
Please update your engine, year, where in the world you are. It helps other people to know where you are and what you have so the diagnoses will be closer to your setup.

Aturek
When the engine is warm, does it start and idle as normal?

 

[Aturek]

Can you please tell us what engine you have? That will be helpful.

V6 gas

 

[Aturek]

V6 gas

2005 V6 gas. live in Wisconsin. once it runs for a few blocks it runs fine.

I did not know it had a cold start valve. that's a new one for me. Have you changed it before? hard to get too?

 

[gazaflash]

Aturek,
Every fuel injection engine has a cold start valve. I haven’t changed it on the Touareg but have on other cars. I’ll try and dig up some info

 

[Aturek]

Aturek,
Every fuel injection engine has a cold start valve. I haven’t changed it on the Touareg but have on other cars. I’ll try and dig up some info

That'd be awesome, Thanks!

 

[TurboABA]

There's more to this story...... you're not revealing all pertinent details.
Have you addressed all the issues in post #3?

 

[Aturek]

@TurboABA

let me know what you want to know.

MAF sensor: Changed and still didnt want to start.
Intake path - Checked for leaks and couldn't find much. One of the hard plastic hoses have a small crack in the vacuum line but Im pretty sure I have it sealed up now.
Plan on checking the throttle body tonight: they are expsensive so want to be sure that is the culprit before buying a new one. what's the best way to know this has something wrong with it?
Timing chain tensioner: I don't even know how to check that - Leaving that as my last option.

 

[TurboABA]

@TurboABA

let me know what you want to know.

Are all 4 of those DTC codes gone?