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Discussion Starter #1
Im having slow starts about 10 seconds cold and 5 or 6 hot on my 99.5 tdi jetta. It started after i changed my fuel filter ( i cranked the motor quite a bit til it started about 10 mins. Letting the starter rest every 10 seconds for 30 seconds).

Ive done some testing. And the car starts up with the coolant tem sensor unplugged. So i replaced it with the one from napa and this did nothing.


I also unplugged it and unplugged the glow plug harness and it fired right up. Which leads me to believe theres a fuel pressure problem at start up wheb the sensor is plugged in .


Is there a way to test this in vcds.
Is it possible that my starter is not spinning fast enough
Is there a way to raise start up pressure or ammt in vcds?

Thanks for any help
 

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Post moved to vcds section.

Unplugging the glow plug harness lets it start up right away? Any codes after you cleared the ones caused by unplugging stuff?

If battery is good it's most likely not a starter problem.
 

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Discussion Starter #3
correct it cranks for 8 -10 seconds cold before starting and 5-6 warm or hot.

if i unplug the coolant temp sensor it starts instantally i'd be supprised if its more than half a second.

i also unplugged the coolant temp sensor and unplugged the glow plug harness and cold and hot and it starts right up

this leads me to believe it has something to do with fuel at start up not glow plugs being on or off.

the new coolant temp sensor i got from napa is a bit different than the old one. the old one had a point on it but the new one is completly flat. they told me it is for the 1.9 tdi tho.

is it the right one? the temp in vcds is accurate.
 

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Discussion Starter #4
and no there are no codes other than the ones caused by unplugging the coolant temp sensor and the one for unplugging the harness. even if i crank the car with the sensor plugged in it doesnt throw a code.
 

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napa is good but they aren't always right.
they try to give me the wrong fuel filter every time I go in there lol
but they're good people. in my town anyway
 

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I thought if you unplug the coolant temp sender that forces the glow plugs to work?

I'm having the same thought as stroud2010 if it was ok before you changed the fuel filter and it isn't afterwards then I would examine the fuel filter again to make sure its sealed correctly. Was it a genuine filter? ;)
 

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Discussion Starter #8
Yes. And i put the old one back in and it still takes awhile to start.


The glow plugs cant work if their harness is unplugged ;)
 

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The glow plugs cant work if their harness is unplugged ;)
I didn't say unplug the glow plug harness did I, only the coolant temp sender?

I'm just saying what Chitty has said on here.
 

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Discussion Starter #10
I know. But I unplugged the gp harness just to test if the motor needed the gp's to start. But it doesent. It just needs the coolant temp sensor unplugged
 
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