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ecu320i
04-10-2007, 01:32 AM
Hi all,

My first post!..........but very technical in nature!
I have a Passat 2001 2.5TDi AKN engine with early rpm turbo lag.
I'm hoping that some kind soul will help, with my ongoing turbo boost problem.
I need someone to post their standard AKN 2.5TDi engine boost on this particular engine, via VAG-COM (this can be done by logging Group 11 (within Engine 01 .....and 08 Measuring) over the rpm range of 1200rpm to 3500rpm whilst in 3rd gear. (apologies Mod.....please feel free to repost this to appopriate VAG-COM questions area if necessary?)
My problem stems from lack of boost in this AKN engine until 2100rpm........see my attachment "AKN mbar Group11 VAG_COM.txt"..... maybe this is normal??..... but, from VW tech data, this V6TDi engine should produce 310Nm from 1500rpm to 3500rpm and my engine only "kicks me in the butt" from 2100rpm....compared with a VW 1900 PD engine whose torque is listed as 310Nm at 2000rpm and to me, feels twice as "poky" as my V6TDi
Please note that I've logged Group 11 via VAG-COM and this lag is evident from my own group 11 logging.........I've removed/checked the turbo variable vane mechanism for the usual sticky/jamming problem, also checked/replaced the turbo N75 solenoid, also removed and cleaned/checked the EGR exhaust turbo valve + associated EGR vacuum valve........and even went to the extremes of blocking this passage via a homemade metal plate.....just in case this EGR was partially leaking boost directly into the exhaust, .....all to no avail!.......I've massive lag until 2100rpm
Perhaps, I've got my expectations wrong with this AKN V6TDi?
In the meantime, I've ordered a MAF ......mine's the more expensive Hitachi MAF by the way!.....it should be here by this weekend..........I'll certainly post my logged VAG-COM findings after fitting this new (expensive!) MAF, but would really appreciate anyones VAG-COM readings from a similiar 2.5TDi AKN and/or their input/diagnostics on my issue.

many thanks in advance,
John (Ecu320i)

VanWheeler
04-10-2007, 08:21 AM
This is about right for this engine. 2100rpm is where the turbo kicks in. I have a 2001 A6 V6tdi. Remapping these helps quite a lot, mine is running at 226 hp 301lb/ft torque.

Feel free to contact me if you are considering a remap or check ot the links in my signature.

Thanks Mark

the.dude
16-10-2007, 10:54 PM
.........I've removed/checked the turbo variable vane mechanism for the usual sticky/jamming problem..................

many thanks in advance,
John (Ecu320i)

Can anyone advise what is involved in checking this mechnism ? Is it straight forward.
Is it also known as the waste gate valve/actuator.

I have been told that mine has a fault - and want to make sure before ordering a replacement (incidentally VW don't do replacement only a full turbo at £1k+ but just found that it is available from Germany).
Thanks
Dude.

ecu320i
17-10-2007, 01:56 AM
Quote:
Originally Posted by ecu320i http://www.vwaudiforum.co.uk/forum/applied/buttons/viewpost.gif (http://www.vwaudiforum.co.uk/forum/showthread.php?p=79480#post79480)

.........I've removed/checked the turbo variable vane mechanism for the usual sticky/jamming problem..................

many thanks in advance,
John (Ecu320i)

Can anyone advise what is involved in checking this mechnism ? Is it straight forward.
Is it also known as the waste gate valve/actuator.Hi The.Dude,
This mechanism is linked via a vacuum actuator to the variable vanes within the turbo assembly. Within the vacuum actuator there is a heavy return spring, so it is very awkward to check manually without first removing the complete turbo assembly.......this involves a lot of patience and time to remove, due to the heat from the turbo which will have probably deterioted/seized most of the nuts/bolts etc. But if you take your time it can be done and the mechanism can be freed of soot ingress etc, with the help of some carb cleaner and elbow grease!
If you don't like the thoughts of stripping this unit out, it may also be checked for seizure or stickiness, in situ, by applying a hand vacuum pump (eg Mityvac) to the vacumm actuator and watching the actuator rod for free, non jerky movement, when you apply some vacuum force. Also check the rod return movement, for free, non jerky movement when you release the vacuum pressure.
hope this helps,
let us all know
Ecu320i

ecu320i
17-10-2007, 02:01 AM
Can anyone advise what is involved in checking this mechnism ? Is it straight forward.
Is it also known as the waste gate valve/actuator.

I have been told that mine has a fault - and want to make sure before ordering a replacement (incidentally VW don't do replacement only a full turbo at £1k+ but just found that it is available from Germany).
Thanks
Dude.

Hi The.Dude,
This mechanism is linked via a vacuum actuator to the variable vanes within the turbo assembly. Within the vacuum actuator there is a heavy return spring, so it is very awkward to check manually without first removing the complete turbo assembly.......this involves a lot of patience and time to remove, due to the heat from the turbo which will have probably deterioted/seized most of the nuts/bolts etc. But if you take your time it can be done and the mechanism can be freed of soot ingress etc, with the help of some carb cleaner and elbow grease!
If you don't like the thoughts of stripping this unit out, it may also be checked for seizure or stickiness, in situ, by applying a hand vacuum pump (eg Mityvac) to the vacumm actuator and watching the actuator rod for free, non jerky movement, when you apply some vacuum force. Also check the rod return movement, for free, non jerky movement when you release the vacuum pressure.
hope this helps,
let us all know
Ecu320i

the.dude
18-10-2007, 07:40 PM
Thanks for the help! I have just today ordered a recon turbo unit, so hopefully this should sort any probs. will post.

stevegrass777
18-10-2007, 09:04 PM
rpm | spec | act
1276 | 2040 | 1213.8
1346 | 2019.6 | 1244.4
1392 | 2009.4 | 1285.2
1438 | 1999.2 | 1326
1508 | 1999.2 | 1387.2
1554 | 1989 | 1458.6
1624 | 1978.8 | 1540.2
1717 | 1978.8 | 1652.4
1810 | 1989 | 1785
1902 | 1999.2 | 1907.4

They dont look right to me specified and actual are way out.
They only seem to catch up at about 1900-2000 rpm.
Are there any audible air leak's from the turbo pipes.
Have all pipe's been checked and seals replaced.
Has the intercooler got a leak.