Help car hard to start when cold

slow02tdi

Well-known member
Joined
Jul 21, 2006
I read through the glow plug 101 thread and tested my glow plugs and they all seem fine. I checked the fuses on top of the battery and they are all good. Are there any other fuses located anywhere else? I don't want to jump to conclusions and just say it is the harness. I'd appreciate any help. It is a 2002 Jetta 5 speed.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
Do a "search" here. There are tons of hard start when cold threads, some of them currently. Lots of reading and suggestions.
Look at the clear fuel line just after the fuel filter. Anything more than a single bubble less than an inch long in there?? If so how about whenits running? Any little stream of air bubbles going thry there? Shouldn't be. The "T" fitting on top of the fuel filter is a common air leak.

Battery?? They need to spin really good to start, not just "turn over" like a gas engine. An OEM type amp hr battery is needed.
Starter?? Mine drags a bit and may need rebuilding before this winter.

Coolant temp sensor may be faulty and not allowing the ECU to actually turn on GPs, although this time of year you shouldn't need them yet anyways. Unplug the CTS and see if cold start is better. The CTS failure is common.
 

slow02tdi

Well-known member
Joined
Jul 21, 2006
I have done searches but like you said there are tons of threads and it gets frustruating looking through them and not finding the info you need. The car has a new battery in it The car starts fine rest of the day once it is warmed up but in the morning I have to crank on it 15 to 30 secs for it to start. Is it possible that it is bleeding air through the night? I just assumed it was a glow plug issue but I will check that t-fitting. Thanks very much for your input and any more ideas would be great. Thanks--Daniel
 

slow02tdi

Well-known member
Joined
Jul 21, 2006
Oh by the way I live in Texas so it's about 70 deg in the morning, It is not exactly cold outside. if that helps.
 

RT1

Veteran Member
Joined
Apr 14, 2006
Location
Central New Jersey
TDI
2005 Golf 1.9 TDI w/tiptronic 09A
Reads like your fuel supply looses it's prime over night from an air leak. If it's not the "T" fitting check the hoses and clamps. It must be tiny leak if
you are able to operate through the day. When's the last time you changed the fuel filter? The one hard start situation I had was after I loaded up fuel at an out of the way mom and pop station. It ran fine for the rest of my run but next morning it took three tries to fire it up. I didn't want to think it was the filter (seeing as I had only 3K miles on it) but I changed it out and the hard start went away.
 

2004STARWARSTDI

Top Post Dawg
Joined
Oct 19, 2004
Location
LAKELAND, FL
TDI
2004 Platinum Gray GLS Jetta / 2006 Silver Jetta with DSG
Hard start in AM

slow02tdi said:
The car starts fine rest of the day once it is warmed up but in the morning I have to crank on it 15 to 30 secs for it to start. Is it possible that it is bleeding air through the night? I just assumed it was a glow plug issue but I will check that t-fitting. Thanks very much for your input and any more ideas would be great. Thanks--Daniel
First thing in AM have someone try to start vehicle while you look at clear fuel line to IP. Is there a lot of air bubbles? If so then you have an air leak somewhere.
 

jettawreck

Top Post Dawg
Joined
Aug 2, 2004
Location
Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
slow02tdi said:
I have done searches but like you said there are tons of threads and it gets frustruating looking through them and not finding the info you need. The car has a new battery in it The car starts fine rest of the day once it is warmed up but in the morning I have to crank on it 15 to 30 secs for it to start. Is it possible that it is bleeding air through the night? I just assumed it was a glow plug issue but I will check that t-fitting. Thanks very much for your input and any more ideas would be great. Thanks--Daniel
Yes, search turns up a lot of sometimes non-relevant info. Good knowledge base, though.
Very possible its leaking down. As others stated, check "T" fitting and/or all connections fuel line related. May be even an IP seal. Check for bubble in morning before start and after its running.
Given your location/temp GPs really should not be an issue, and if they weren't working you would probably have a CEL on.
 

slow02tdi

Well-known member
Joined
Jul 21, 2006
i had somebody start it while i watched the clear fuel line, and there wasnt a whole lot of bubbles in it. After it started there were a few small ones but not excessive. The filter has about 10,000 miles on it.
 
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