!!!!!!Hard cold start 04 BEW Jetta !!!!!!

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
I have a 2004 Jetta Tdi Last year it started fine in subzero temperatures. This year it started having trouble starting in anything below 5 deg c so I changed the gloplugs with original 7v ones, checked and confirmed they were working, it didn’t help.

Installed a zero start inline coolant heater between oil cooler and coolant tempurature sensor housing, after a few hours of being plugged in it usually started fine. However recently no matter how long it remains plugged in she will not start. The gloplugs don’t stay on long so I cycle the ignition on and off x10 and it usually starts.

I checked the codes with a BlueDriver and she threw a P0726 code after long crank. During the crank the rpm’s jump from 0-500 initially then lay at 0 for remainder. (Rpm gauge works fine when running)

Even after a half hour + of her running and up to tempurature when shut of she will not turn back on sometimes.

The ECM and gloplugs recall was NOT performed due to the nearest dealer is 10 hours away.
Timing belt, fuel filter and intercooler all changed recently.

What is causing this?????? Could it be the crank shaft speed sensor or the wiring to it?
 
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Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
If the car will not restart after half hour, then there is an issue outstanding which has nothing to do with the GPs.

In your other thread, you used the term "frostheater". Here you are using "zerostart"

This leads me to thinking that your hose routing may not be providing the convection you need for the engine block to warm.

Are you able to:
1) take a picture and post up here in the thread of the heater installation
2) scan the car after an hour (or more - just track the amount of time) of it being plugged in and heating, and post up the engine coolant temperature. Also (at the same time) take a temperature reading of the engine - an IR thermometer works best, but a hand on the block also works here. If the coolant is 50 deg c, the engine block should be quite warm if the coolant is circulating.
 

mrowens33

Veteran Member
Joined
Aug 29, 2012
Location
Brookfield
TDI
2004 Jetta sedan slushbox, 2004 Jetta wagon manual( my Noble Steed)
I'm no pro but your glow plugs might need to have the Ecu updated to work properly. I was having similar issues when it would first start. I changes to the same glow plugs you did, had a stage 1.5 tune with glow plug update done. It's been starting way better insingle didits ever since. You could probably get the dealer to flash your Ecu for less than a tune
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Windex and mrowens33 have it covered.
Outside chance maybe the in-tank pump is getting weak.
That code seems strange, don't know that I've ever seen that on a '04.
 

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
Windex this is the heater I have installed

the bottom nozzle is connected to the oil cooler outlet and the top nozzle goes to the coolant temperature sensor housing. Its installed on the same level as the oil cooler, the heated coolant convects up to the coolant temperature sensor housing.

cannot get picture of installation because the engine bay is too congested and unable to get full image.
 
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joep1234

Veteran Member
Joined
Jan 2, 2014
Location
NC
TDI
former '04 Beetle TDI, now 2x '15 Audi Q5 TDI's, 2007 Dodge Ram 4x4 6.7
If your tach isn't reading while it is cranking, you may have a bad crank sensor. Also have you changed the coolant temp sensor? If it is not reading correct, your ECM will get the wrong information to make it run while cold and not control your GP circuit like it should. You need to get a green top one if it needs to be changed.
 

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
I have not changed the the temperature sensor, gauge reads about 35 deg after the coolant heater is plugged in for about a hour or so at -6 deg C outside temp.
The rpm jumps from 0 to 500 then goes to 0 and stays there until the engine finally starts, then it reads fine.
Below is the code it threw after prolonged cranking, cleared the code, doesn’t come back until the next long crank time.
http://https://www.dropbox.com/s/dqw7pe9b7u9o2jm/Photo%202018-01-19%2C%209%2009%2044%20PM.png?dl=0
 

Wilkins

Veteran Member
Joined
Aug 19, 2005
Location
British Columbia
TDI
05 Jetta Wagon 5sp, 10 Sportwagen 6MT
I think your hard start cold and almost no start could be different issues. I’d check the wiring to the crank sensor. The sensor is down low on the front side of the block near the flywheel and wiring runs to a connector which iirc is attached to the vacuum reservoir. They are not well protected and if chafed that could be it.

I can’t check ‘my’ Mk IV at the moment but it sounds to me as if the coolant heater is installed properly, and at -10 C the car should start without any trouble without the heater anyway. The GP light should come on for 10-15 seconds and if it does not my first thought is that the ECU Is not reading temperature properly, as joep said, Unless I am mistaken the Mk IV engine temperature sensor is a weird one though, it has two outputs, one for the gauge and one for the engine management. Only way to check it is working right is with a VCDS Or equivalent while the engine is running/cold. To make it more complicated there is a 3rd temp sensor which reads intake air. I don’t know which one controls the GPS but I think it is coolant.

Glowplugs - the PD went through two recalls for glowplugs so it is important to ensure you have the right ones installed. The first recall installed plugs which would not start the car below about -12C, the second one fixed the problem with an additional controller in place. There are at least three different GP’s depending on which recall or no recall. The originals or the 2nd recall GPs work fine as long as they match the recall level. I’ve started after a 3 day soak at -30C without the block heater plugged in.
 

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
Last year I would park the car at the airport for 3 weeks while I travelled away for work. Never had an issue starting it then even when temperatures would drop to -20 with the original glow plugs, 7v.

I removed the GPS and connected them to the harness while grounding the threaded section to the block. They all glowed for about 10 seconds at -8 deg C with the engine cold.

Thanks for the replies, I’ll check the wiring for the speed sensor.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
I have not changed the the temperature sensor, gauge reads about 35 deg after the coolant heater is plugged in for about a hour or so at -6 deg C outside temp.
Yes, but is the block warm?

I worked on a self-install zerostart car once where it would heat the coolant in the hose and little else. The CTS is not necessarily accurate for the temperature of the block...
 

JB05

Top Post Dawg
Joined
Oct 20, 2005
Location
Il.USA
TDI
Golf,2005,anthracite blue
P0726 is one of the DTC's that came up after long cranking in frigid weather. The codes never came back after I deleted them with my Ultra Gauge. The problem was indeed the fragile cable on the crankshaft position sensor which I had disrupted recently when I changed the t-stat. I have the new sensor, but have yet to change it. Topside looks like quite a challenge on the BEW.
 

Bluecharm

Member
Joined
Sep 28, 2017
Location
NEWFOUNDLAND
TDI
2004 BEW Jetta
Ok so it’s been some time since I have replied to this thread but I have an update. Ordered a new CP sensor and tried to get the old one out but the electrical connection was tough so just as a try I sprayed it with penetrating fluid. I also added cetane boost to the tank and left it for the next day. Tried to start in -13 deg C the next morning and it fired right up. Been starting in cold weather ever since. Not sure if was the fuel additive or the penetrating fluid on the connector that helped but so far so good.
 
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