2,5 tdi AKE running rough when warm.

**Finas** · 24-02-2014,11:36 PM

Ok, will see how much mg mine takes to read.

in your experiments have you ever driven the car without the pressure/temperature valve that sits on top of the fuel filter, or have you ever replaced it?

I thought that mine had been changed but just noticed today that it wasn't. Date code predates car build date by two months.. Hummm... Just ordered one.. PN: 057127247D

I also ordered a N75 valve. A guy over a French forum wrote that replacing it cured it's a4 2.5tdi pre-injection error

**ametlib** · 25-02-2014,10:10 PM

Again, good thinking !
No I have never driven without the valve , but yes I have replaced it and nothing changed

sorry.
About a new N75 fixing pre inj. error I don't know, but I had the bark at idle too, also not related to the boost system.
Strongly believe that the only options left is fuel starvation,
or something external of the pump is actually making the quantity adj. valve to be powered to late or early.
If you want to take a closer look to that posibillity the wiring at the pump are as follows :
1- can low
2- can high
5- shut off
6 - minus-ground
7-power + from 15
8- rpm signal
9- k-line

**Finas** · 25-02-2014,10:41 PM

does your ECU has block 030 ? on BAU engines it logs rpm, injected quantity and pre-injection status. Mine doesn't have it. it just appears empty. Maybe it's the way it is on my ecu, or it is empty because my pump doesn't send the information. In this cause your's should do it as it has been refurbished and should have newer firmware.

**ametlib** · 27-02-2014,11:48 AM

Originally Posted by Finas

does your ECU has block 030 ? on BAU engines it logs rpm, injected quantity and pre-injection status. Mine doesn't have it. it just appears empty. Maybe it's the way it is on my ecu, or it is empty because my pump doesn't send the information. In this cause your's should do it as it has been refurbished and should have newer firmware.

I checked, but block 030 is empty, I believe that is more of an ECU matter, my pump have a new ECD. Since yours is running in and out of "bark mode" maybe you could check ( hot engine at idle) how much the ECU uses the advance solenoid
in both "bark mode" and not. Also what happens in measuring block 13 & 14 , " bark mode and not.

**Finas** · 13-03-2014,05:06 PM

My bark problem was fixed by adjusting the ECU maps related to pre-injection. What I noticed was that in the situations where the engine barked, the pre-injection was off. There were other situations when the engine was not barking and pre-injection was also off, mostly at above 3000rpm but below 2500rpm and pre-injection off this almost allways lead to the engine barking.

So, it's imporant to remember that I have high-flow nozzles and the bark only appeared after replacing the nozzles ( I also replaced the turbo and IC at the same time ). The engine didn't bark when running with stock nozzles+stock turbo+ stock IC.

**ametlib** · 14-03-2014,01:54 PM

"I bought the car one and a half year ago, and from time to time it throws an error ( 17583 pre-injection turned off. P1175 - 35-00 )"

Good! you fixed it, but the fault was there before you changed the injectors, and I'm sorry to say I suspect it's still there .....( but I hope I'm wrong though)

Tweaking the pre inj. map is indeed the work of a wizzard, but I suspect it's only camouflaging the real fault, another thing is that the ECU cuts the pre inj. at mid and higher rews because it need the time elapced between pre- and main injection to inject fuel.
Otherwise it will have to add the extra fuel AFTER the main injection, resulting in lower power ( at high rews) and MPG will be suffering....
Sorry for beeing a party killer, but as I said I hope I'm wrong.....

**Finas** · 14-03-2014,03:29 PM

I'm not sure the pre-injection error has been fixed. I haven't seen it anymore but the car barked even with no error, and the bark is 100% gone.
The timming between pre and main can also be changed. I think there is a map for that. In my case no loss of power and regarding MPG I dont have enough km's with it to answer.

The thing is that the car never barked before changing the injectors and it only started barking after that. And I noticed that the bark was related to Actual SOI being displayed, and we ended up finding that it meant that pre injection was off, and so, by logic, the car barked when pre-injection was off. Now that pre-injection is on, it doesn't bark anymore.

Can you relate your bark with Actual SOI being displayed?

**ametlib** · 14-03-2014,04:51 PM

Definitly yes, even if I would'nt say it barks now the engine sound still become rougher when the coolant temp reaches 78,1 C and the Actual SOI is beeing displayed

**ulinux** · 03-04-2014,09:02 AM

Made the change on Finas ecu. It is definitley also barking with stock nozzles when pre injection turns off. I have an A6 with BAU engine, and it is completly stock regarding hardware and it barks as well when pre injection is turned off. Pre injection is handled verry different comparing A6, A4, AKE, BAU and BDH and its combinations. So on some pairs you will notice barks very well and on others not that much.

**ametlib** · 04-04-2014,09:28 AM

Hi,
Yes, guess you're right. The newer 2 plunger pumps makes the engine more quiet , probably because it's running pre-inj all the time.
But if I got this right the older 3 plunger pumps ( ending letter A-E) just cannot run pre-inj after warm up phase, because they can't handle the extra heat ?
Anyway, the bark I had was not a normal variaty. Another strange behavior is when it change gear ( automatic) . If it have a bad day, it just cuts fuel completly, and leaves me hanging over the steering wheel for several seconds before it picks up again....