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VW MKIV-A4 TDIs (VE and PD) This is a general discussion about A4/MkIV Jetta (99.5-~2005), Golf(99.5-2006), and New Beetle(98-2006). Both VE and PD engines are covered here.

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Old January 31st, 2012, 03:31   #1
Join Date: Jan 2012
Location: Knoxville
Default 2002 Beetle TDI Hard Starting in Cold Weather


I am new here............but I have down some reading and searching on your site for this issue.

This beetle happens to be my mothers and I have been driving it around to get a better handle on what the issue really is.

Day 1 (morning):
26 degrees out, turn the key glow plug light only on for about 2 seconds. I cycled it twice more and tried to start the engine. All I got was some stumbling and once I pushed the pedal down about 3/4 the way down, it lit right off.

Day 1 (evening):
45 degrees out, turn the key on and still the glow plug light is on about 2 seconds. I cycle it twice more and try to start the engine. This time no stumbling and it didn't even try to hit. I pushed the pedal most of the way down and it started stumbling and lit right off.

When I got home that night, I unpluged the engine coolant sensor and tried the glow plugs like I read on your site. This time the glow plug light was on a least 15 seconds.

Day 2 (morning):
35 degrees out, turn the key on and still the glow plug light is on about 2 seconds, started fine after I pushed the pedal most of the way down.

I should add that the engine starts fine after it has been run even a short time........which leads me toward the glow plug issue. Also, the battery and crank speed seem to be fine. I done some full throttle runs up hills to test degrading power (fuel restrictions, filter, etc.) but everything seems good.

I also read that retarded injection pump timing could be the reason for the hard starts in the cold.

At this point, I am thinking that replacing a $8.99 coolant sensor would be a cheap gamble unless you guys can point me in another direction.

Any ideas?

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Old January 31st, 2012, 04:16   #2
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Join Date: Sep 2005
Location: Ohio USA
Fuel Economy: mid-upper 40's city upper 50's - low 60's Highway

I also drive a 2002 NB and I seldom have any problems. You should not need to have your foot on the accelerator. Do you have the heater fan, head lamps etc on? Have you checked the glow plugs?
Joe Meehan
2002 NB Silver Ohio BAA HUM
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Old January 31st, 2012, 04:19   #3
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Join Date: Dec 2001
Location: St Louis

Sounds like a loss of pump prime. I'd inspect the pump itself for any signs of fuel leakage (wetness). It is not a coolant temp sensor or glow system problem most likely.

See my FS thread:

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Old January 31st, 2012, 21:06   #4
Join Date: Jan 2012
Location: Knoxville

I had all the electronics off except the radio. The glow plugs and harness are fairly new.

When it does start......no plume of smoke or rough idling.

Checked all fuel hoses, lines, and filter..........no leaks

It seems as though its not getting fuel till it lights off.

What would keep it from fueling on start up
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Old February 1st, 2012, 05:03   #5
Join Date: Oct 2011
Location: WS,NC

This sounds like our beetle. I was starting to think that maybe my oil was too heavy. I use a FrostHeater regularly and it's still slow to start. I also have the EGR stuff removed, so I'm sure it's not clogged.

Last edited by CycleStar; February 6th, 2012 at 08:32.
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Old February 6th, 2012, 08:27   #6
Join Date: Jan 2012
Location: Knoxville

I went ahead and replaced the coolant sensor and waiting on a cold morning to see if the glow plugs cycle.

I personally think that something is keeping it from getting fuel on startup.

Do 2002 Beetle TDI have a in tank lift pump? If see, I was thinking I could remove a line from the filter and check flow with the key on.

You have to pump or keep the pedal down in order for it to start cold and parked overnight or if you have parked it a little while. If you shut it off and make a stop then crank up...........all is well.

It really acts like it is loosing fuel prime............. but doesn't have the rough idling stumbling issues after it starts.

Any Ideas?
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Old February 18th, 2012, 02:15   #7
Join Date: Sep 2009
Location: Snohomish, WA
Default hard start

Your hard start does possibly sound like a lack of fuel problem. As others have said, you shouldn't have to even have your foot on the accelerator if everything is working right. The fuel injection pump has a governor (which keeps your engine from overspeeding) but it also puts the engine at full fuel for starting (at low RPMs). The fuel injection pump may be misadjusted or the governor not working properly. The fact that you don't put out any partially burned fuel (smoke) until the car starts also supports the idea that you are not getting adequate fuel.

Another possibility is that you have an air ingress into your fuel lines. My 2001 Jetta has a clear fuel line going into the fuel injection pump. Maybe yours does, too. If so, you can check to see if there's some air in the line. Check this while the engine is running, especially right after starting. My Jetta had air but I moved hoses and clamps and fixed it. Air causes the most problems when the vehicle sits a good while because it congregates at a high point in the fuel system and can cause a "plug" which has to be "pushed through" or "filled" when you start the car. That can cause the injection pump to deliver inadequate fuel to the cylinders when cranking after sitting a while.

Just my two cents worth--maybe it's not worth two cents.

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Old February 18th, 2012, 16:19   #8
Curious Chris
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Join Date: Jun 2001
Location: Indianapolis, IN
Fuel Economy: 47/42/38

Have you checked the injection timing? Late last fall I had quite a few members stop over at my house to have their timing adjusted. With retarded timing the car will start in ok in warm weather and then poorly or not at all in cold weather.

The engine does not get any fuel until the starter spins the engine at IIRC 350rpm.

The 2002 does not have a lift pump the injection pump sucks the fuel in which is why air leaks can cause problematic starts. I added a lift pump to my car for top end performance but it also provides very nice cold starts; oh my injection timing is in the upper half of the injection timing graph as I own Hex-Com VCDS.
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