help...random hard start 2006 jetta tdi

cptdi

Well-known member
Joined
Feb 28, 2005
Location
ottawa canada
TDI
06 jetta tdi shadow blue
I've had random hard starts (summer/winter) since the car had 40000km on it. The dealership replaced fuel pump at 40000km in the tank. This winter I've had 3 times where it takes about 5 minutes of cranking (on and off) untill car fires up. Last night I fired her up...been sitting in a garage for a week and it started and ran no problem, today..wife goes to take the car and no start, I get home and crank it for about 5 min (on and off) until it finally started to kick and then fire up...what is going on? Anybody have any ideas? Car now has 107000 km's on it and has always had oil changed at dealer and serviced there....dual mass flywheel was replaced 7000 km ago but I don't think the 2 are related. Car kinda chuggs when cold too.
 

cptdi

Well-known member
Joined
Feb 28, 2005
Location
ottawa canada
TDI
06 jetta tdi shadow blue
update..have it narrowed down but no idea why it's doing what it is. Car can sit for 1 week and start no problem..if I start the car and run it for less than a minute and shut it down..2hours later it won't start easily. Got it started last night after about 4-5 minutes of cranking..let it run in driveway for 45 minutes and put it back in garage..this morning I reached in and turned the key..fired up right away and I turned it off...2 hours later I leave to go for a rip to the store and it starts after 3 cycles of cranking..it can sit for a week now and will fire up right away..I just don't get it..what am I missing? Obviously fuel is not leaking back because it will start a week from now no problem but after a quick fire up and shut down she will not easily start again next time.
 

TDI-Geek

Well-known member
Joined
May 28, 2007
Location
Ohio
TDI
1.9 Jetta TDI
I have a 2006 with this same issue, Started last year and they replaced the fuel relay. No problem for 10 months then hard/no start again. Just got it back from the dealer and they replaced the lift pump. So far no problems but as you know it is an intermittent problem. I was also told that the fuel relay has been upgraded for some reason so that is where i'm going if it acts up again.
 

Sweeps

Veteran Member
Joined
Jul 24, 2005
Location
Orillia, Ontario, Canada
TDI
None currently. MK4/5/6 Jetta's in the past.
Have a look at the wiring harness under the air box.

I had two severed wires that go to the Crank Position Sensor / Engine Speed Sensor or whatever its proper name is.

I had similar issues, but not quite the same, then it got worse and the car wouldn't start at all. (Plus I got check engine light / no tach / oil light etc)

I'll put money that you have chafed / worn wires in the loom. Have a local guru have a look, if that's the issue, they'll most likely be able to repair it.

Now my car had 280,000km on it, but you could have the issue with so few miles on the car.
 
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