2.0 tdi 140 slow crank/start in cold? (Video inside)

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master83

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Hi!

I feel like my newly bought A3 is a little slow to start when it is been sitting over night for example, and I was wondering what your thoughts are on the video below.

It has a fairly new (and expensive) battery (1 year old).

It´s got four new glow plugs as all of them were faulty when I bought it (took 1 minute of cranking to start before)

I feel like there should be more "omph" when cranking - as it feels slow and takes about 8 cranks to start.



Thanks
 
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Although the battery is only 1 year old it could still be faulty. It needs testing to be 100% sure that it is okay.

You need to check the terminals on the battery are fitted correctly (seated properly) and that they are tight. Also check the connections to the starter motor and the engine/battery earth points
 
Seems to me that the battery is struggling judging by how the lights on the dials go out during cranking. Connect your battery to another car battery with the car running and then crank yours, if the cranking is quicker and lights don't go out then it points towards battery issue.
 
Ok I´ve been doing some diagnosis now trying to figure out this slow cranking during cold starts.

First of all I have had the battery tested by a garage, and they told me it is 100% OK. They also checked the connection to the starter motor and found nothing wrong.

Also no fault codes in VCDS related to the engine. All four glow plugs are new and working.

The battery is about 1 year old and the inspection light on the battery is green (see picture). Specs for the battery is Sunnak SB740, 74 Ah, 680 A. I have charged the battery for a full 3 days with the biggest C-tek battery charger, and it reports the battery as being fully charged.

However, it is still slow cranking when cold. This is a VCDS log of a cold start with a 100% charged battery:
,Time, Engine RPM
,4.03, 0,,,,,,
,4.34, 0,,,,,,
,4.65, 79,,,,,,
,4.97, 119,,,,,,
,5.28, 114,,,,,,
,5.59, 122,,,,,,
,5.90, 125,,,,,,
,6.22, 127,,,,,,
,6.53, 127,,,,,,
,6.84, 128,,,,,,
,7.15, 130,,,,,,
,7.46, 130,,,,,,
,7.78, 134,,,,,,
,8.09, 137,,,,,,
,8.40, 133,,,,,,
,8.71, 154,,,,,,
,9.02, 139,,,,,,
,9.33, 182,,,,,,
,9.65, 493,,,,,,
,9.96, 705,,,,,,
,10.27, 432,,,,,,
,10.58, 535,,,,,,
,10.90, 652,,,,,,
,11.21, 347,,,,,,
,11.52, 0,,,,,,
,11.83, 0,,,,,,

As you see, it actually failed to start this time. It started, but died right away. Started on the second attempt.

Then, after driving it for 10-15 minutes (coolant temp at about 55C) i logged this start:
,Time, Engine RPM
,3.12, 0,,,,,,
,3.43, 0,,,,,,
,3.74, 58,,,,,,
,4.06, 336,,,,,,
,4.36, 1113,,,,,,
,4.68, 1112,,,,,,
,4.99, 1014,,,,,,
,5.30, 926,,,,,,
,5.62, 850,,,,,,
,5.92, 827,,,,,,
,6.24, 803,,,,,,

Then it started right away.


Would you say it´s time for a new starter??

Thanks
 

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Mate the only thing i would say about the battery charger is its not big enough, (on their website CTEK XS 0.8 Car Battery Charger - the smartest battery chargers in the world!) it will charge up a 32Ah battery, but will only condition larger ones (your 74Ah one), maybe the battery is fit but not fully charged, just a thought.

mines even slower to start, a 170, but my battery is a bit too small i think 61Ah/540A, so an Varta E44 is on its way

Regards

Robbie
 
Hi. I have one of the biggest C-teks, not the smallest one :) So it supports well over 100 Ah´s
 
Oh OK, read it but looked at the link and it was a small one ;), apologies, hope you get it sorted

Robbie
 
I think the starter may be the problem mate if connections and battery are fine
 
would a struggling starter motor cause the dash lights to go out like that though?

i currently have the slow crank issue when hot (its booked in the garage on 7th january) but my battery tests fine and i have no dash light fade when starting
 
T8DPR said:
would a struggling starter motor cause the dash lights to go out like that though?

i currently have the slow crank issue when hot (its booked in the garage on 7th january) but my battery tests fine and i have no dash light fade when starting
Click to expand...

Definitely starter motor !
 
Can anyone confirm that the ECU needs at least 150 rpms during cranking for it to add fuel? As you can see on my cold start, it doesn´t fire until it reaches 150+ rpms.

Btw: Ordering a new starter tomorrow and will let you know how it goes.

Thanks
 
U said u had ur glow plugs changed. What ones did u use? Oem? Pd140 or 170?

Reason i ask is cos 170 uses 7v and 140 uses 4v. If uve got the wrong plugs, they'd work for a while but eventually burn out. So glow plugs could be struggling to warm up. The fact its -5 doesnt help but it looks like its starting quicker on the 2nd attempt, is this normally what happens?

When was ur fuel filter last changed?

Tried premium diesel and/or injector cleaner?
 
I got OEM ones from Audi, checked the part number on them and they matched the ones I removed so that should be fine. The issue is not that it doesn´t start when cold, but slow cranking. The second start was a warm start, and the starter cranks much faster due to less friction in the engine and DSG (300+ rpm) so it starts right away.

It has a complete service history, so fuel filter is changed according to the schedule.

Yes I use premium fuel, but have not tried injector cleaner.

I am going for a new starter, and see how it goes.

Thanks for the input.
 
I would definitely say duff starter motor. Happened to my mates A3 TDI several months back. Seemed fine once warm but slower when cold .
 
Allright :)

Replaced the starter tonight, and so far it´s looking very good! I have yet to try a cold start, but the hot start is at least twice as fast cranking than before and it starts right away.

Will post cold start results tomorrow, but I´m 99% sure the problem is fixed.
 
mine does this as well it feels as if its not going to start then it does and drives perfectly fine, i had it scanned via vcds no faults were detected its a 2006 BKD, when i turn the key to start the interior lights and the dash lights all dim down slights as well as the headlights if they are on before the car is started, could mine be a battery fault ?
ive jump started a few cars using my battery and it seems to jump other cars fine
sorry for hijacking the thread ...

i was also looking at your video the temprature is -5 that could be the issue as its way below freezing and its the first time starting the car ?
 
No it should start fine even below -20 C.

Will post a new cold start video soon with the new starter.
 
audi upgrades
this happened to my 05 tdi dsg was the starter motor since it got changed the car starts no problem now
 
This is the first cold start after replacing the starter with a new OEM one (nothing else changed):

 
Last edited by a moderator:
That's better mate eh was it expensive and was it hard to replace?
 
I live in Norway, so prices are maybe more here than you guys are used to. I paid about 270 punds / 330 EUR.

Not hard at all to replace yourself. Just had to remove the air filter box, and the starter is right underneath it. Two bolts, two connectors and done :)

Just remember to remove the negative battery cable beforehand :)
 
Sounds way better than before, mines no where near as bad as your first video
 
I am glad you got to the bottom of the problem mate and that's not as expensive as I thought it might be
 
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