2006 Jetta BRM PD While starting stumbles

Hi all, am traveling and Jetta engine at start up has been stumbling when hot, takes extra second or two to start. When cold fires right up. Put new battery in no diverence. Has 111K on it. Acks like a loose connection on starter, and the stumbling has been getting worse. I fear I won't make it back to Vancouver, Wa. am in Louisiana now, soon to be in Texas on I-10 West. Any help much appreciated, I did read a post that said get a new battery, but that didn't help. Thanks

Check it for codes. Is the Check Engine Light on?

No check engine light, havn't checked for any codes am traveling I suppose I could have a auto parts check for me, thanks for quick response Not sure if I should put message in Mk5 forum

I there is no Check Engine Light then there are probably not any important codes. What do you mean by "Stumbling"? Are you saying it cranks slow or starts stumbling once it starts?

after it starts it runs fine, while cranking it cranks ruff, like stumbling

You might want to check the Torsion Value of the cam. You will need VCDS to do it.

What would the torsion value on the cam have to do with this? Please explain, thanks

There are some well qualified Guru's, who are also members here, in Texas. May want to look at the Trusted Mechanics by State stickie at the top of this 101 section.

My PD also stumbles if i set the torsion value at more than 3.5
It is more noticeable on cold mornings. It doesnt stall but you can feel the stumbles from the driver seat, about one per 10 seconds.

Readjusted torsion to 0.5 and no more stumbles

ride0169 said:

What would the torsion value on the cam have to do with this? Please explain, thanks

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Putting it simple:

The torsion value is the relative position of the cam to the crank. This affects the timing adjustment for mainly the fuel. This is because the pd cam actuates the injectors.

The pd engine is very sensible for this. A few degrees of difference cause different things which are well documented in this site.

Adjustment is not difficult but you need vcds.

Ok thanks but mine runs fine after it starts. It's just while cranking the starter it stumbles for a second or so. So would the torsion value on the cam make it stumble while starting?

Also could be a failing cam or crank position sensor

This sounds awfully familiar to my sisters BRM Mk5. But the difference is, it happens to her car when it's -20 and colder. When it's "stumbling" it's on the verge of running and the engine is turning over fast enough for the tachometer to read the revs, something like 300, correct?

Yes but mine only cranks for about 2-3 seconds then starts and runs fine. When cold fires right up. Only does this stumbling when hot. Like PGM said maybe crank position sensor

PGM thanks that maybe on it's way out, is there a way to test the crank position sensor? Is it a easy removal and install? I'll have to find out where by the crank it's located. I'm is Washington state it's raining and cold and no garage, can't wait to look into this. Appreciate the tip thanks

I'm not aware of any way to test it besides a replacing it.

It's located on the block right next to the oil filter housing

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There is also a cam position sensor on the PDs

I similar issues and replaced both the cam and crank sensor. I replaced them at the same time so I'm not sure which one actually solved it

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The crank position sensor for the 06 Jetta BRM is part of the rear main seal and is anything but easy to replace. You would have to pull the tranny. The cam position sensor will not stop an engine from running, but may make it hard to start.

If you have access to a VCDS, and there are several around the state, I would check the torsion value, idle compensation. There are some issues with the wiring. For example, if your torsion value is '0' and moving the cam timing makes no difference, you have a bad cam position sensor. I doubt it, as it starts easily cold. There can be hot start issues related to the fuel temp sensor.

The crank sensor is more likely. The plug for the crank sensor is difficult to remove. It is about even with the bottom of the oil filter housing and goes into a hole toward the rear main seal. With the engine running, check to see if there is any movement of the wire that will cause the engine to 'hiccup'.

There are some known grounding issues with the wiring. That can also be a problem. Whenever there are gremlins, I check the grounding acorn nuts by the ECU and under and around the battery. We clean the corrsion and apply an anti-corrosion grease. Once done, that sometimes eliminates 'weird problems'.

Good luck. If you get in a bind, there are several ppl we know in TX and OK