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-   -   2005 D3 3.0 TDI Lazy start solved - please read! (http://forum.a8parts.co.uk/showthread.php?t=13499)

h20wes 10th October 2017 03:27 PM

2005 D3 3.0 TDI Lazy start solved - please read!
 
Hello

I am new to the forum, I have a lovely 137K silver 3.0TDI facelift sport. It is awesome, but it always has had lazy start issues when hot, it used to be intermittent and I never really worried, but recently got worse. I bought a brand new bosch silver battery, which didn't really do the trick. So bought a proper new starter and fitted, no different. Then realised the battery wasn't being charged by the alternator to any great extent. So bought a new alternator.....no change.
I then realised that the voltage was dropping from 14.2v at the alternator to only 13.2 at the battery. After stripping out most the engine bay and under wheel arch covers, I realised that the point where the battery lead and the engine loom meets is a small box in the inner footwell of the drivers side (cover just pulls off) this was mega hot and the voltage was only 13.3v here. I unbolted the big terminal which is crimped from the factory. The engine harness side was loose and flimsy.
I then built a mega aluminium cage around it to protect the pdeals and carpet then heated it up with a monster blow torch and fed about 2metres of soldier into it to strenghten the connection.
Bolted it all up and presto! perfect starting and perfect battery charging.
The loom was at fault,to replace (which i contemplated) would take some serious hours (6 I reckon) and the part number is 4E0971224J but its the connection at the end! save yourself some money lads and check this first before you start chucking parts on like me!

Johnmed 10th October 2017 04:05 PM

Interesting. Not a problem I’ve otherwise heard of on the D3.

What a shame you had to replace things that weren’t at fault. I had a similar issue on an old 320i about 15 years ago. Would only start when the engine was earthed to the body with a secondary lead. Indy told me about it and I cleaned the earth strap and tightened it up, all was well in the world.

Either way, great result in the end for your car.

Norretal 11th October 2017 08:24 AM

What an impressive first post, Mr h20wes, most people start off on here asking for help or trying to sell something +++

Get on the introductions sections and tell us more about your car, and photos are an absolute necessity ;)

M-A8 11th October 2017 08:30 AM

Very very interesting, thank you for sharing it with us +++
Glad it's all sorted now.

Replacing this wire shouldn't by that hard. If you use a metal cable tie and tie engine bay end/eye (old cable) to cabin end/eye (new cable) you should be able fairly easy to pull the new cable in. That's my assumption from memory when I looked there last time months ago.

IT 11th October 2017 10:18 AM

Welcome,

Good result in the end....

I've moved the post to D3 engine bays to help people find it in future for reference +++

North2007 6th February 2018 10:53 AM

Quote:

Originally Posted by h20wes (Post 133571)
Hello

I am new to the forum, I have a lovely 137K silver 3.0TDI facelift sport. It is awesome, but it always has had lazy start issues when hot, it used to be intermittent and I never really worried, but recently got worse. I bought a brand new bosch silver battery, which didn't really do the trick. So bought a proper new starter and fitted, no different. Then realised the battery wasn't being charged by the alternator to any great extent. So bought a new alternator.....no change.
I then realised that the voltage was dropping from 14.2v at the alternator to only 13.2 at the battery. After stripping out most the engine bay and under wheel arch covers, I realised that the point where the battery lead and the engine loom meets is a small box in the inner footwell of the drivers side (cover just pulls off) this was mega hot and the voltage was only 13.3v here. I unbolted the big terminal which is crimped from the factory. The engine harness side was loose and flimsy.
I then built a mega aluminium cage around it to protect the pdeals and carpet then heated it up with a monster blow torch and fed about 2metres of soldier into it to strenghten the connection.
Bolted it all up and presto! perfect starting and perfect battery charging.
The loom was at fault,to replace (which i contemplated) would take some serious hours (6 I reckon) and the part number is 4E0971224J but its the connection at the end! save yourself some money lads and check this first before you start chucking parts on like me!

Great first post Wes thanks

peiiider 3rd March 2018 12:19 PM

1 Attachment(s)
Took a look at this connection in my own car today, as I have started suspecting some charging problems in addition to unexplained current draw.. Have a reported batt voltage during driving of 13,2-13,7V according to VCDS, but the measured current keeps jumping up and down between +10 and -5A. That the current into the battery would be negative during driving sounds strange to me..

Anyway, I opened the box and this looks like it has been hot, with the too small heat shrink and the «mark» on the lid at the same point. Think I will try the soldering method myself and see if anything improves.


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