Does this sound like PD injector wiring loom issues?

[Tommy10]

Hello,
This is my first post here so please be gentle!
I bought a 2005 A3 2.0 tdi recently with the BKD engine and 90k miles and l love the car to bits!
However, I find I do have a few issues and am hoping I can have a little advice!
The car is a reluctant starter from cold; if I press the accelerator down whilst turning the key the car quickly fires and the initial surge in revs seems to smooth things, if that makes any sense?
If I don't press the accelerator whilst turning the key/operating the starter it wheezes and sounds like it is running on 3 cylinders for a second or two , I sometimes get a puff of smoke too but don't know what colour it is, it definitely doesn't sound healthy!
From hot starting is immediate and perfect.
The car performs great, although as it warms up the idle seems lumpy, this seems to disappear once hot?
Lastly on the motorway I can't make up my mind if there's a misfire/judder or not!
It goes like stink but there is definitely more vibration than I would like through the body of the car , at first I thought that it might be that the wheels need balancing but after having searched on here am thinking that the PD injector loom might be dodgy?
I've tried scanning the engine with a cheap code scanner but no faults were found?
I know how hard it is to diagnose faults like this online but do these symptoms sound like the loom is at fault?
I'm really hoping the injectors are OK!
I should add I changed the fuel and air filters recently , it uses no coolant at all but the economy seems poor, I'm getting 45mpg on my daily 40 mile motorway journey to work?
I'm hoping to buy the proper Ross Tech VCDS cable soon, are there any tests I could do to diagnose what is wrong?
Would it be worth changing the PD loom anyway, but at about £100 to buy it's a bit expensive to change needlessly?

Cheers.

 

[millsy4002]

Might be worth getting the injection timing checked, mine was well off and had some similar issues, not saying it's that but might be some help


Sent from my iPhone using Tapatalk

 

[Tommy10]

Thanks, is that a check I can do once I get the Ross Tech cable?

 

[millsy4002]

Yeah but it's not a easy thing to check if your not sure what to look for, do some research on here, mine was done at a tuner and was down 15bhp purely on the timings


Sent from my iPhone using Tapatalk

 

[desertstorm]

Sounds to me like it's been remapped and possibly not too well. If the injectors have been changed or the wrong map has been put on the car you can get the issues you are describing. Also the vibration you are feeling is it around 1800-2200 Rpm when you are accelerating in a high gear. This is typical of a mapped diesel and is possibly if you are feeling this you need to back off the gas or change down a gear and accelerate in a lower one.

 

[Tommy10]

Thanks for the replies guys....
Yes it has been re-mapped (I'll come to that in a minute) about a week ago.
The vibration was evident on the first journey home after buying it when driving it at motorway speeds, like I said I put it down to perhaps a badly-balanced rim or two....same for the poor cold-starting it was there from the minute I had it.
About a week into ownership I bought an expensive tuning box (not going to name them) and had a devil of a job fitting it , had real issues with connecting it to the engine round-connector as it simply didn't want to mate .
Anyway, after about 20 minutes faffing about I eventually got it to fit and went for a short drive.
The performance wasn't exactly what I was expecting ( not much of an improvement really) and then I stopped for 30 minutes.
After re-starting the car it became evident that all was not well, it was shaking badly with zero go and I limped the mile or so home doing barely 30mph.
The seller was contacted who immediately decided that I had not fitted it correctly and they demanded photos etc of the installation location!!! I wasnt impressed at all.
I did this and found that if I removed the tuning box the car ran perfectly , with it fitted it ran like a dog,no matter what position the jumper pins inside were fitted at...
The tuning box was put on and taken off about 3 times (somehow it got easier to do!) but it would only run OK without the box!
I was so peeved by their poor customer service I returned the device and asked for my money back, which they gave.
I decided then that I couldn't be bothered with messing about with the engine loom any more so decided on a remap and for convenience went for a Bluefin by Superchips.
This was easily fitted and the before and after difference was incredible.
Could an existing bad loom have been damaged by the faffing around trying to get the original tuning box to fit? I'm now concerned that the round connector might have twisted when I was trying repeatedly to get the damn tuning box on; I didn't force anything at all though.
Tbh the vibration is at about 2000rpm ie 70mph in 6th gear when cruising steadily, on acceleration it seems very smooth (and very rapid)! but as already said it was like this before the remap...?

 

[Tommy10]

Well I gave the engine a scan today with VCDS and no fault codes we found.
I then decided to have a look at the group 4 measuring blocks and this is the result;


Address 01: Engine (03G 906 021 LG)

11:42:53 Group 004: Pump-Jet Valves
819 /min Engine Speed (G28)
0.0 °BTDC Injection Start (specified)
6.6°KW Injection Duration (specified)
-2.9°KW Torsion Value

Can anyone tell me what the above values mean, or what other tests I can do to pinpoint the problem?
During the time I was logging the data the idle speed was very lumpy and the engine wasn't hot (had been standing for 3 hours after a 40 mile journey) , come to think of it, it only idles lumpily when the engine is relatively cold?

 

[Tommy10]

I've been doing a bit more digging and looked at measuring blocks 13 and 15 as well.
All the injectors seem to be in balance with each other, and the fuel consumption at idle seems to be around the 0.6l/hr mark.
The only thing that seems way out is the torsion at -2.9?
So, I'm going to have a go at checking the cam timing as it seems to be too retarded?

 

[Tommy10]

Well, I thought I should report my findings from today.
Armed with the measuring block info that the torsion was -2.9 and that the fueling was 0.4l/hr I decided to have a go at adjusting the front cam first and then do the rear....
The front cam went OK, and after about 5 attempts got it to zero.
The rear cam was adjusted clockwise a fraction of a millimetre and on starting the engine a massive difference was noted!
No more lumpy idle, it sounded different and more importantly , the judder at motorway speeds has gone.
Now that I've adjusted the cam timing its brought home to me how easy it is to do and check via VCDS

 

[Tommy10]

Well the cold-starting still isn't perfect so my thoughts had turned to the glow plugs...
No fault codes from the engine are showing up on VCDS so I turned my attention to the glow plug circuit and under one of the measuring blocks for the glow plugs it came up with the value of 12.46v at terminal 30?
Is this low?
Could the battery be at fault?