A2 1.2tdi max 100km/h, jumping out of 5th gear

M

mrbizzy

Member
Hello.
I have this A2 wih 1.2tdi engine for few weeks now. very satisfied with the car except one problem that should be sorted.

While the car is relatively cold all goes well but on a highway it reaches only 100-105km/h in the 5th gear and no further acceleration. so the rpm sits little above 2000 and the consumption is displayed as 4l/100km. Even when it shifts down to 4th gear it does not ad much and speed rises to 110km/h not more.

That is annoying, especially because here are no recognized A2 (especially 1.2tdi) specialists who could i trust to fix it. But that is not all, unfortunately.

When it gets warmer, about 30min driving, the 5th gear starts to "pop-out" and sometimes releasing acceleration pedal and pressing again helps to activate the gear, but sometimes it requires to stop and start the engine to gain the drive-ability.
What happens is that gear selection shows E or D but no gear numbers are displayed and no gear is selected. Also accelerator pedal is sometimes active but sometimes dead as the engine does not react on it any more.

When this happens the only way to drive further is to manually switch gears and leave in 4th. then all is ok and car runs smooth and quiet.

Also i noticed that when this happened and i tried to keep driving on and on there started a loud noise from gearbox in the first gear, then in the second and later in all four gears. but after a easy driving in 4th gear on a highway with some 30min stop in the middle the sound disappeared.


Any suggestions where to start looking for a fault/solution?

p.s. a side question - there is a button (big round) on the side of the gear knob but it does not do anything when pressed. should it??

Casper from Latvia
 
Hi!

I'm admin for the Swedish 3L site (lupo3lclub.se), Instead of a bunch of messages back and forth, send me a PM with a phone number and I'll give you a call.
After a solution has been found it will be posted here.
 
You need to scan the car with VCDS. When was the last gearbox/clutch basic setting done? Changing out of fifth may be possibly due to the clutch slipping or the system assessing that the clutch is slipping (it compares engine revs with gearbox revs) but may be due to a poor contact somewhere (usually the gearbox rev sender). Another cause may be a shortage of hydraulic oil.

RAB
 
The lack of top speed may also be due to the turbo VNT mechanism needing a clean.

RAB
 
OK, so in autumn i put the A2 aside due to my pessimistic thinking about the problems i had with it. now as snow melted i drove it to Audi service and they diagnosed that the gearbox problem was actually a lack of knowledge of some private mechanic who had replaced the gearbox switching robot but did not run the basic setting and/or some screws were not tighten at all and therefore i had lost the reverse gear and it was jumping out of 5th gear. after 1 hour and 50EUR bill the car is switching gears just fine. have not tested it on a long journey in the 5th gear so am not 100% sure yet but will do it soon.
However i still have the issue with the power - in neutral and in 1st and 2nd gears i can run the engine up to 4500 rpm, but in the 3rd it is not willing to rise above the 3000rpm mark. not to mention that in the 4th and 5th gear it is not willing to rise at all. I did not ask audi to check on that as i had forgotten about it already during the winter.
RAB mentioned VNT mechanism cleaning. but i wonder is it possible to diagnose with VCDS first? and is his a DIY job?
when the car is fixed and in good shape i am willing to sell it but cant do it before i am sure it is in good order.
 
mrbizzy said:
However i still have the issue with the power - in neutral and in 1st and 2nd gears i can run the engine up to 4500 rpm, but in the 3rd it is not willing to rise above the 3000rpm mark. not to mention that in the 4th and 5th gear it is not willing to rise at all. I did not ask audi to check on that as i had forgotten about it already during the winter.
RAB mentioned VNT mechanism cleaning. but i wonder is it possible to diagnose with VCDS first? and is his a DIY job?
Click to expand...

Maybe but probably not. It might be simpler than that though. Check that the vacuum pipe (the end of which is rubber) is still connected to the VNT actuator and has not disconnected itself because the rubber has perished (as mine did a few weeks ago). Otherwise cleaning may be required. Can you move the actuator rod up and down? The job is potentially DIY but judge for yourself:
http://www.a2oc.net/forum/showthread.php?22534-VNT-Turbo-De-Coke&highlight=turbo

RAB
 
RAB thank you for the link to instruction thread.
i can do it myself as i have tools and garage where i can keep he car in case i do not finish same day.
And looks like i will have to do it because the VNT actuator is so stuck that i can barely move it at all and thus only for a few mm.
And i noticed, that when i start the car it picks up the speed ok for the first two gears but then when it gets to third and then back to first or second it is noticeably slower.
hopefully turbo will be ok, otherwise will have to buy a replacement. one friend has exactly 1,2tdi model for spares right now.
 
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