A6 AKE quattro jolting

[loodak]

Hello everyone, long time reader, first time poster i apologize in advance for the wall of text

I have a weird problem with my car, and was hoping someone might have had a similar issue and can help.

I got the car few months ago.. its done 210.000km.. i moved countries and needed a beater car for long journeys with comfort, until my family and i settle in and get a descent one.

It starts great, runs great, no smoke, etc.. nothing odd for 99.9% of its usage.. BUT .. sometimes, usually on the highway.. it just jolts violently for a second or two.. 2-3 jolts ..and after that keeps going like nothing happened... or does it again in a few km.. or doesnt for a few hundred
i cant describe properly how it feels like.. its like its moving a few inches back and forward real fast.. like if you had a manual.. drove at 50/60km/h .. poped the clutch in fifth, revved it silly and dipped it back real fast a couple of times.. or try to shift a diesel into fifth at 40km/h

so as it happens really rarely why am i here?
well the local mechanics diagnose it from the door of the shop.. one said engine injectors, one said fuel pump.. one said transmission ecu.. each one had a different guess.. as i plan to sell the car in a year or so i dont wanna "guess" my way out of couple thousand euros

i scanned the car with an "audi" diagnostics .. thats what the guy said.. i know he had a handheld bosch diagnostics thingy.. no error codes
then i scanned at a buddy with vagcom .. i got 00550 start of injection regulation / 27-00 implausible signal - interminent .. if someone can shed some light on that, it would be very apresciated as i haven't been able to google that combination of codes anywhere

what more info i can give that might help:
-i've read a lot of this forum.. i like to read up on stuff.. fjtwelve's topic kept me awake a few nights xD .. so i know the common issues these cars have
-it starts up great, no smoke.. maybe a puff in the morning, but i think my battery is nearing its lifes end
-no hot start issues..
-the gearbox is running smooth and dandy, no sudden shifts, jolts etc in everyday driving
- i know the guy i bought it from.. the service history seems fine
-it doesnt smoke even under heavy load.. i had a buddy drive behind me and floored it.. nothing out of ordinary
-i cant seem to pin down anything related to why its happening.. i could be going 80, or 200..hot day, cold day, wet, snowy, regular.. can be on acceleration, on decelearation.. just using cruise control
-one or twice i had something similar happen when i was in neutral at a stop light.. i could feel it just shuddered and shut off.. if its related i guess under load it doesnt "drop" enough to shut off
-when it does happen.. the consumption doesnt change.. it doesnt go into limp/safe mode.. i've had a few thousand km done without it happening.. then happen a few times in one trip
-initally i thought it was bad fuel.. felt like that.. but i changed a lot of petrol stations, so i've eliminated that

as i do mostly city and highway driving i'm not too afraid of it as it could be an issue on a B road when overtaking in the oposite lane.. but i'm afraid it could be something silly , causing a bigger problem somehow.

please help, the gremlins are driving me mad.. i love every bit of this car, i dont wanna have to pass it on

 

[loodak]

ta-dah.. new gremlin attack today.. poped the hood open to see if i can find air bubbles in the fuel line.. but alas the pipe is so dirty you cant see trought it.. didnt want to tinker with it myself. messed around trying to trace cables/hoses to see if any one them is snagged or something.. wiggled the lot a bit to see if anything pops out..

start the car.. start going to get breakfast.. i get a red oil light on the dash as soon as i move 2m .. 2m after that it goes away.. about 50m down the road it pops back up again.. and nothing for the next 1km.. i let the car cool down for 20-30 minutes and checked the oil level.. just a bit above minimum.. last time i checked it was 15 days ago, done maybe 1000km since then.. before this i didnt notice ANY oil missing out the ordinary.. filled up 1/2l oil that was leftover from the last service.. no oil light.. too it real gently back home just in case. never got an amber light before this Oo

so with my tiny mechanical knowledge.. i've put two and two together.. could it be that all the times it "jolted" it actually got oil into combustion chamber and went bananas? then again i never noticed any smoke from behind.. and i do pay atention to my mirrors

atm i'm very frustrated with it.. i'll just sell it on if it does another wacky stunt on me
on the other hand its grown on me in this brief time.. i know adams is a master at them.. what does it take to bombproof these engines.. not looking to tune, just last long with regular servicing and such. i'd rather dump few thousands into it , then sell and get a newer one with its own set of problems.. i should note that labor is cheap here.. so are parts from the scrappers.. so if can switch stuff from another engine type instead of ordering from the UK it would be tons cheaper for me.
<3

 

[loodak]

ah ****** briliant.. i've gone to check it once again since i came back.. it stood still for maybe 1h .. its at maximum on the dipstick.. luckily i didn't go out and buy a few more liters to fill it to max.. i'd overfill it.. so back to square one.. and now i got another gremlin to deal with.. i'm guessing a sensor has gone bonkers.. where is it located?

edit: a few hours later and here i am completely insane.. oil level ok.. i think i found the sensor, but a picture would be awsome to confirm.. the outer isolation "tube?" has come off.. and its bent funky.. fired the car up.. took it for a few laps around the block.. 5-6km.. tried low revs,high revs,swirwing (in case it was caused by fluids moving too much),stop-start again.. aaaaaand nothing.. runs peachy... i gotta go get the lil on from kindergarden, then the mrs from work and go for lunch.. wanted to make sure it wont pop up again at the worst moment.
what puzzles me is that the level WAS physicly down to low at one point.. can a sensor do that? or shall i look into a new oil pump

i'll try and book a mechanic on monday.. but no specialists here afaik, so fingers crossed and both eyes on what they're doing.

 

[Shargo]

Neither sensor nor faulty oil pump should affect the oil level AFAIK.
Just to be clear, procedure to check the oil level:
Run the car so the engine reaches operating temperature.
Park it on a flat spot (even a slight slope will affect the reading).
Turn of and let it sit for 5 to 15 minutes so the oil has time to trickle down.
Remove dipstick and wipe it of (with a clean rag).
Re-set the dipstick (straight down and fully seated), pull it up and check the oil level.

Think I can check on the laptop with VCDS (VAG-COM) later today to see if I can find something about that error code.

 

[loodak]

for checking, i've been told ideally you check when the car is cold.. if not then let it sit on a flat spot for 15-20 minutes so the oil has time to return all the way down.. nobody told me the car should be at operating temperature. thanks.. is 5 minutes really enough for a bigger engine?
i'd be real grateful if you could look it up.. i got a vacation planed in 2 weeks , i'd love to find the culprit before that

 

[TYphoon GB]

The code points to timing....either the cambelt set up or the dreaded fuel pump death.
The pump can suffer from ECU failure (its the black lump on the pump) and or the internals getting fouled by rust (water in fuel etc).
Bubbles in the fuel line could suggest the latter.
I'd say check the timing and if that's good your looking at a pump repair.
Normally there is a set of codes and you get engine and traction warning lights.
You could try 50cc of two stroke oil in each full tank of fuel (no more than 50cc in a full tank) can keep it going for a bit.

http://dieselbob.co.uk
Audi Bosch Diesel Pump A4 / A6 / A8 2.5 TDI V6

 

[loodak]

i'll try and check the timing with a proper mechanic asap.. the thing is , the car isnt givin me any warning lights when it goes bananas.. i've been reading and searching forums for a month and i can't find anyone with same symptoms.. usually its lack of power, then goes into limp, then dies and cant restart.. mine jolts like being rearended a few times and acts like nothing happend.. no lights, no warnings, nothing in limp mode.. i'll report what the mechanic thinks/finds. ty

 

[adamss24]

I would check and replace the gearbox oil and strainer/oil filter. Make sure you buy genuine oil, nothing else...

 

[loodak]

your the man i wanted to hear been stalking the forum for quite some time now. what about making an AKE solid? i read you swaped camshafts from another one, but didnt follow trough what else is involved

 

[adamss24]

You can get the heads from BAU/BDG/BDH engines and fit to your AKE block, however i would use solid cams- the AKE ones will fit if they are in good nick.
Alternately you can buy solid camshaft kits from kolbenshmidt which are forged and came with INA lifters and rocker arms. They are very good value for money and very log lasting- you won't have to touch the engine again !
I have just fitted a BDH 180Bhp engine in my a6, engine is put together from bits: BDH 180Bhp block, 1x BDG head and 1x BAU head. The BDG heads are machined more from the factory but as i ported the heads it did not make any difference. Sold my old engine to someone which his passat BDG chewed a cam so not a bad deal either for both parties !
I had to do the swap because i was building this engine for a while + i had a slipping clutch so it made sense to pull the engine off and do it all in one go ! Here are a few pictures:

 

[2stroke]

You can get the heads from BAU/BDG/BDH engines and fit to your AKE block,
however I would use solid cams- the AKE ones will fit if they are in good nick.
Alternately you can buy solid camshaft kits from kolbenshmidt which are forged and came with INA lifters and rocker arms.
They are very good value for money and very log lasting- you won't have to touch the engine again !
I have just fitted a BDH 180Bhp engine in my A6,
engine is put together from bits:
BDH 180Bhp block, 1x BDG head and 1x BAU head.
The BDG heads are machined more from the factory but as I ported the heads it did not make any difference.

adamss24

So in your opinion, one should seek a BDG head if you have to change.
This is because they have the best flow.
...Or ?