MK4 TDI glow plug issue

[Grey_Smoke]

This summer I bought a 2001 mk4 TDI to replace the gutless wonder.  At the time the glow plugs were not working so I replaced them with Beckarnlies (spell?), which was all Lordco had, I thought that this had fixed the problem because when I removed the old ones whey where completely shot.  But it's has just gotten cold (-4-5ºC) in the last week and the car is not starting well when cold.  to me it seems like the glow plugs are not firing, or not firing for long enough. 

it is throwing code P0380 Glow plug / Heater Circuit A

I'm running Shell Rotella 5W-30 full synthetic oil
The engine temp sensor went in September so I replaced it with a green one. 
I have checked the glow plugs with a multimeter and they seem to be good. 
I have checked the fuses on top of the battery and they are good. 
I have disconnected the eng. temp sensor and checked the glow plug bus bar and it was getting 11.8 v. at all the plug connectors. 

I'm at a loss as to what the problem would be.  Any help would be appreciated

I can get access to a VAG-COM if I need to. 

Grey_Smoke. 

[CRSMP5]

those harnesses fail at the glowplugs..

[Grey_Smoke]

I tested the Harness but pushing my multimeter probe into the glow plug socket, which would have contacted the end of the probe with the back of the socket, which would be up stream from the glow plug connection point, is there any way to clean the harness before I replace it? the Guy at Lordco suggested Fluid Film, but I didn't tell him that it was for an electrical connection and on the can it says that it's an electrical insulator. 

[cyrus #1]

What do you mean by not starting well?  Is there smoke?  Is it misfiring?  Is it turning over slowly?

[Grey_Smoke]

When the temp drops below 0* C it turns over really slowly, and the colder the engine the slower it turns over. Even when the engine is relatively warm, as in running in the last couple hours, it turns over slower than it should.

[8v-of-fury!]

Not a glow plug issue.

I can start my m-TDI below 0* C with out my glow plugs even hooked up on me engine. It isn't the happiest camper for a few seconds but it smoothes out quickly.

[CRSMP5]

mine starts different on a 70*f day vs a 20*f day.. so listen to what you want... but it will tak fw xtra revolutions to fire when they do not work..... som epeopl ewould pipe dream you into thinking their junk starts the same...

1 glow plug out is all it takes.. just makes it slower to start... will it start.. yep.. vs a old idi..

id remke the harness.. and see what happens..

[8v-of-fury!]

Starts different? Yes.

Struggles? No.

Pipe dream? Angelina Jolie and a 67 Stang? Where.

It may very well have a dead gp.. causing that starting issue? Noway.

[cyrus #1]

I would suspect a weak battery.  Checking voltage during cranking will tell a lot. Faulty glow plugs won't cause it to turn over slowly. 

[8v-of-fury!]

I would suspect a weak battery.  Checking voltage during cranking will tell a lot. Faulty glow plugs won't cause it to turn over slowly. 

Thank-you. Weak battery, weak starter, bad connections or wires with high resistance.

[Grey_Smoke]

ok, I sprayed some electrical contact cleaner into the harness and then coated the contacts in dielectric grease.  this morning it seemed to start a bit better, but not much.  The starter could be an issue, it's some times not disengaged immediately after the car starts since I got it. 

[ricosuave]

My bet is on the battery - went through the same issue about a week ago

Changed my battery and all is well.

Maybe take it in and have it load tested?

[Grey_Smoke]

Checked it with a specific gravity tester and it tested good, I will be testing it with a load meter tonight.

We checked the voltage during cranking and it dropped to 9.7 V. Both times we tested it.

[ricosuave]

yeah, I think it dropping that low is trouble.

I seem to recall mine dropping to 11.2V and having issues

[cyrus #1]

9.7v is too low to turn over properly.  Make sure you get the proper battery as well.  It should be a group 94 R with at least an 80 Ah rating.  I got my last one at Wal-mart and it has worked out well so far.