2004 Jetta PD BEW rough cold start rumble-stutter at idle until warm

[Mawcus]

2004 Jetta PD BEW 5 speed 170k miles. Takes longer than it should when starting it cold. About twice as long as it should. Once running it stumbles and shudders (visible on tachometer). Runs really rough for several blocks but after a few minutes it smoothes out. This is a recent problem ive noticed in the last week or so. Seems weird because its summer and its starting the way it does when temps are way below freezing.

 

[curtludwig]

Watery fuel? Time for a new fuel filter?

My 2 TDIs start just fine until below zero, starting below freezing is no different than above except I have to wait for glow plugs...

 

[Mawcus]

Fuel filter should be good. Replaced it when i did in tank fuel pump last winter

 

[Jake_S]

Whats the mileage on the engine? Have you pulled the valve cover and checked the cam/lifter for wear?

Jake

 

[kiara]

IMO it's the leaking injectors - symptom was tied to cold days, cold engine. Once it warmed up all was good - for a while.

Only way to check the injectors, I believe, is to bench test them and new ones are not cheap. Good luck!

 

[Dimitri16V]

Check the cam first . Engine can't consume enough air till the worn lifters pump themselves
Injectors is the last thing you want to check

 

[Mawcus]

Cam is good. Have about 177k on car. Replaced cam at 150k with Frank06 stage II cam. Of course to complicate things I havent noticed stumbling in the last few days. Pretty mild weather up here. Low 60s in the mornings. Upper 70s low 80s during the day. Last few days after parking all day at the park n ride there was no stumbling on start up. See what it does tomorrow morning i guess. When i first noticed the problem it literally sounded like rocks were in the engine. It sounded the same as it has on the handful of winter days when we had single digit temps.

 

[Mawcus]

Well problem has been worse the last few days. Cranks longer than it should to start and runs real rough for several minutes. Started it cold yesterday and drove it after dark for the first time in awhile (lots of daylight up here in summer). Noticed the lights were flickering. A few months ago i had a flickering light problem that was solved by replacing wire/cable from the alternator to the battery. Flickering went away. Now the flickering is back but only flickers when engine is cold and stumbling. Seems to go away when its warmed up and running smooth. I guess I'll go check the voltage between the alternator and battery again. Not sure what else to check.

 

[Tdijarhead]

Check your alternator pulley, it might be seized. Causing your battery not to be fully charged, which of course could cause some longer than normal starts.

 

[Mawcus]

Alternator pulley should be good. Replaced it a few years ago but i guess I should check it again. Seems like it would be pretty obvious if the pulley was seized. Factory one was real noticeable when it went and it went downhill quick. Probably check the alternator itself. Kinda at a loss and haven't had time to poke around under the hood to figure more out. Its just driving me nuts starting it first thing on a 60 degree morning and it sounds like a tractor being starting on a sub zero temperature day with the lights flickering like crazy.