06 jetta tdi wont start when cold, glow plugs cycle normal, and no smoke.

I have a mkV that runs great 48-52mpg but some times it will not start unless I crank on it for a long period of time, generally when the engine block has cooled below 32 deg. but not always. What is weird is that it usually starts immediately after venting the bleeder on the fuel filter. Last year it had a lift pump replaced.

It seems like a lack of fuel problem, and the MIL is not on.

I am a Ford diesel mechanic but have no clue how these TDI diesels create fuel psi and inject, so there for I am lost when it comes to 05 and later TDI stuff.

I love the car to death but I am close to filling the inter-cooler up with diesel and letting the B*&!@ run away until it melts down and post the video on youtube.

It has unitized injectors. Fuel pump in tank, tandem/fuel pump on rear of cylinder head and each fuel injector has its own high pressure pump built into it.

If you would like help, you need to supply us with more information. Like, mileage, last fuel filter change, is the lift pump running, is there fuel pressure to the filter housing, is the ASV open?

All I can say is before they would replace my lift pump( intermittent hard start in cold weather) the VW representative wanted all lines to be checked for air leaks, at the time the car was under warrantee. But since my dealers service manager thinks diagonostic is a last resort and at the time the car was under warrantee they decided to replace the lift pump instead which as it turns out would have been the most likely culprit from what i have read on this site.

Suction leaks in the fuel system can cause low horse power, fuel starvation problems, and pump cavitation. We usually find them by pressurizing the fuel lines with air and hit them with soapy water mixture.

Ive read on here the tandem pump can be suspect for leak back in the fuel system and might need changing or some have installed a check valve with success.

Good luck.

thanks guys, the jetta has 90k on it and has no loss of power.

Are you getting and CELs?
What is the tachometer doing during the periods of long no start? Is it registering RPM?
It it is not registering RPM at the no start, does it register about 2 to 4 seconds after starting?
Is your battery in good condition?

Two questions:

1) When you vented the bleeder on the fuel filter, did fuel or air come out?

2) Where do you suggest I start looking for a P1408 code on a 2004 Freestar?

on the freestar 80-90% of the time the EGR system is working properly but the DPFE sensor does not register that there is any exhaust flow. it is a small square box with a 2 or three pin connector and two vacuum lines leading into the EGR tube that comes out of the exh manifold.

To check egr flow apply vacuum up to the EGR valve, and if the engine begins to run like crap you have good egr flow and the DPFE sensor is not reading the flow.

-- small amounts of fuel comes out, I do this with the key in off position.

--I feel like there is something in the engine control module keeping the fuel injection from turning on, like an engine cxl. mechanism. All other things check out to me (can this happen ????) It does not have a remote start.

When it's cold is the only time this happens?

What about if it starts easily, can you shut it down then try again to see if it starts hard? LOL! I'm not sure where I'm going with this, but I'm just throwing things out there, some of which should be thrown out with the trash, surely.

I guess I'm trying to figure out how to differentiate between an electrical problem and a fuel problem. Someone mentioned watching the tach during starting and that is a good idea since there have been more and more of the CKP being reported going out.

CXL=cancel??

Look for a PM.

If your not cranking fast enough it won't inject fuel. Try charging the battery or use the boost setting.

had a similar problem....

remove the lid of the fuel filter housing in the engine bay

remove fuel filter and CHUCK

remove dirty fuel in filter filter housing

THOROUGHLY clean filter housing and filter housing lid

replace with new clean OEM filter either from dealer or a mann hummel filter

recharge filter housing with fuel by unscrewing bleed screw and cycling ignition a few times

try this and see if this work.

second thing to check, and quite possibly replace would be ALL of the rubber fuel lines in the engine bay for any nicks/cuts/breaks/tears/breaches where they could be letting air in and replace these immediately

good luck

PM Sent.