04 golf hard starting after harness and glow plugs

e_v_a_n · Nov 8, 2018

Hey all
So yes, I searched. Still can't figure it out...
Car starts hard when cold (freezing and below), takes maybe 10 seconds of cranking after key left in on position until glow plug light goes out. Kind of stumbles to idle.
I replaced both harness and glow plugs. P0671 to p0674 codes thrown. Once it starts, it runs well.
What else can I check?

k_pt · Nov 9, 2018

Were the codes clear and the same codes come again? Do you know your compression values?

JETaah · Nov 9, 2018

What is the brand and part number of the glow plugs you replaced the old ones with?

Tdijarhead · Nov 9, 2018

I think there was a recall/reflash of the ecu on 2004's, has that ever been done? Something about 5v vs 7v glow plugs.

How does your cam look?

How old is your starter?

Hussman · Nov 9, 2018

I know on my old BEW I had to cycle the glow plugs at least 2-3 times if its under 0 degrees fahrenheit. Mine started -25 quite a few times, but it wasn't liking it. I now have an ALH and have noticed the glow plug light stays on much longer than my BEW did.

Good luck,

Hussman

k_pt · Nov 9, 2018

You can change the glow plug time with VCDS. Also ALHs usually have higher compression values, which help ignite diesel easier.

JETaah · Nov 9, 2018

k_pt said:
You can change the glow plug time with VCDS. Also ALHs usually have higher compression values, which help ignite diesel easier.

Not on a 2004 BEW engine without tuner intervention.

k_pt · Nov 9, 2018

JETaah said:
Not on a 2004 BEW engine without tuner intervention.

Correct, I was assuming that could have been done on Hussmans ALH.

e_v_a_n · Nov 9, 2018

I'll have to check the brand and part for glow plugs replaced..
The ECU reflash is a good question! Thank you for that, I'll check with the dealer
Thanks all for your input

BobnOH · Nov 9, 2018

Yes, you need to know what plug goes in your engine, your car may or may not have been modified to use a different voltage plug. Would have been a hardware (plugs) and software (ECU) modification. Harness, relay remained unchanged as far as I know.
Sounds like you're all over that stuff, once sorted out we can move on to the other things.

e_v_a_n · Nov 18, 2018

Just wanted to update this (I hate it when people fix things then don't share the results)
After some investigating it turns out the ecu was flashed for 7v glow plugs. I bought some new ones, and now it starts great in these cold MN mornings

k_pt · Nov 19, 2018

Great!

04 golf hard starting after harness and glow plugs

e_v_a_n

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k_pt

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JETaah

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Tdijarhead

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Hussman

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JETaah

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k_pt

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e_v_a_n

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BobnOH

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e_v_a_n

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