HELP! More Rough Idle, Juddering and Rev problems
Looking for some more help and advice. I've had a load of problems with my car over the past few months, and all of them have been fixed now. But I have these persistent little things that my garage are either unable (or maybe unwilling:P) to fix. Note; the car is under warranty and garage have been carrying out repairs free of charge so far!
Car is a 2007 Audi A6 2.0TDI S-Line Auto, approx. 80k on the clock.
1. The car idles quite badly, but not all the time. It happens on almost every journey, but not every time the car is stationary. The rev needle bounces up and down between approx 850-1000 rpm, the car noticably shakes, MPG read out starts dropping and the car smokes a bit (and i usually notice a diesel smell while it's doing this). This problem comes and goes.
2. It revs too high when driving at low speed. It's like it hangs on to a gear too long, so it revs at around 1300-400rpm at 20mph and stays at this rev speed while I'm slowing down, then the revs suddenly drop to normal when the car is almost at a complete stop. Same as above, this problem also comes and goes.
3. The car judders at low speed with low revs. For example, if I'm driving at around 20-25mph on a flat and clear road, with revs around 1100rpm and I'm barely touching the accellerator... Just maintaing that speed with very gentle throttle. In this situation the car starts jerking and juddering... it almost feels like i'm tapping my foot on and off the accelerator in too high a gear. If I put my foot down a bit it responds and is fine, it only seems to be low speed/low power/low revs situations that it does this.
The car has had so much work done to it, and so much replaced (see list below) that I'm really keen on keeping hold of it now. But it seems like my garage are at the point of giving up on it and I'm after any advice or info on what could possibly be causing it. From a few hours of Googling and reading, I've come across some suggestions already:
Change gearbox fluid and filter.
Remove and clean wheel speed sensors.
Check torsion values.
Check idle stabilisation valve.
Check/clean throttle body.
Unplug battery and reconnect to allow throttle body re-alignment.
EGR valve fault
Software and EGR (Apparently a software update is available to stabilize the idle and reduce egr flow to prevent the EGR allowing to much flow which results in a judder)
What I'd like to know is; in anyones experience are these things likely to resolve the problem? What would be the best order to tackle this list in, and is there anything else worth considering?
This is whats been done on the car so far that's worth mentioning:
• New/Remanufactured Engine fitted
• All injectors removed and sent away for full testing. All OK.
• Injector seals replaced.
• Injector wiring loom replaced
• Dual mass flywheel replaced (and, I’m told the Torque Converter too)
• Oil sump removed, cleaned sump and pickup
• New oil pump
• New lambda sensor
• New oil pressure sensor
• New MAP sensor
• Vacuum hoses check and inspected
• New fuel filter
• New air con pump
• Cambelt kit and water pump
• Full service
The car has recently been to Audi main dealer who wanted a load of hours and bags of money to start fully investigating loads of things, including repeating things that my garage have already checked.
Sorry for the massive post, got a bit carried away! This problem is doing my head in. It's a real shame too, because apart from idling and these low rev/low speed issues, the car drives beautifully. Sometimes feels like a brand new car!
Re: HELP! More Rough Idle, Juddering and Rev problems
Difficult to reply on an iPad but here goes.
Bad idling common, almost always injectors OR cam timing, i.e. Torsion value.
It does not have an idle stabilisation valve or throttle body (as such) as it is diesel not petrol
It is a CVT so does not have a torque converter...
Lambda sensor.... can you PM me that cars reg.
Advice, pay to have another VAG experienced garage take a look and do a PROPER VAG specific FULL code read and clear and arrange another scan for a week later, get print outs of both. If the new garage won't play ball, find someone who will.
Re: HELP! More Rough Idle, Juddering and Rev problems
Hi, thanks very much for your advice.
The injectors have been tested by a diesel specialist next door to my garage, and also shipped off to a specialist company and came back all OK. Injector seals and wiring has all been checked and replaced as necessary.
I won't bother looking any further into idle stabilisation or throttle body then!:D
OK, thanks for confirming about the torque converter. It was someone else who mentioned about the torque converter as they'd had a similar issue with their automatic. I have an invoice that shows the flywheel was replaced this year - an assumption was made that the torque converter was done at the same time.
Lambda sensor - I have PMd you.
I can try and get my garage to check the cam timing, and get it back to main dealer just to book in for a full VAG error code read and clear, and then another one a week later. Is this to clear any old codes, drive it for a week and then see what "genuine" faults I get on the new readout? The car is still under warranty, and they haven't been able to fix this idle/running issue yet, so as far as I'm concerned - I shouldn't have to be paying for the diagnostics yet! :) Although, if it's relatively low cost, I might do it myself and then take it back to my garage to fix it under warranty. Any idea on cost of a fault code read?
Thanks again for your advice.
Re: HELP! More Rough Idle, Juddering and Rev problems
Also, if anyone knows of a good Audi/VAG specialist garage in the Plymouth/Devon area that isn't a main dealer and would be able to do a full code read and clear ... Please drop a recommendation in here! :D
Re: HELP! More Rough Idle, Juddering and Rev problems
Vehicle Identification No. |
WAUZZZ4F07N120*** |
Model |
Audi a6 Avant 2.0 TDI |
Date of production |
12.02.2007 |
Model year |
2007 |
Registered |
28.03.2007 |
Sales type |
4F5 0FH |
Engine Code |
BRE |
Transmission Code |
JQL Multitronic |
Emission standard |
EU4 DPF |
Exterior colour Code |
LY7G |
The flywheels on BRD engine CVT cars often fail, we have done quite a lot. Bosch and VAG say (and I agree from multiple bad experiences) that it is not possible to accurately check these injectors outside of the new production or Bosch reconditioning factory test jig. It is like ECU repair companies, I simply don’t trust the results of bench testing as after 35 years of being given the run around by these types I have given up. I even sent a special apparently UK un-testable TTRS ECU back to Bosch in Germany for their specialist testing and they told me it was fine and it wasn’t….. so that sent me around in circles for days!
Find a VAG specialist who will read and print the codes out for you and then clear them, then go back a week later to see what has come back as this will be a more representative report of actual codes which are not all the story but all most garages are capable of reacting to.
Re: HELP! More Rough Idle, Juddering and Rev problems
Have you tried disconnecting the anti shudder valve / air control flap wiring socket connected before the egr? It wouldn't necessarily have been replaced when the egr was done.
Would be worth taking off the valve housing and checking the gears aren't damaged.
Whats it like on start up?
Re: HELP! More Rough Idle, Juddering and Rev problems
Starts up ok. Never had any issues with it starting...
I'm going to get the fault code read as advised above, and then take the results to my garage along with other recommendations on here, so I'll ask them to check that too!
They're starting to get a bit funny about it due to the amount they've had to spend out, but I'm going to keep on pushing them, as it's not .y fault that the money they've spent so far hasn't fixed one of the problems, and now it's developed more!!!
Re: HELP! More Rough Idle, Juddering and Rev problems
Quote:
Originally Posted by
Crasher
The flywheels on BRD engine CVT cars often fail, we have done quite a lot.
Hi Crasher, I do have an invoice from my garage that states the flywheel has been replaced in June this year. I'm just trying to get the car booked in for the error code read and clear today, followed by another a week later. I've been told that they can provide me with the log file each time, so will post the results on here and then see what I can get my garage to do under warranty!
Thanks for your help
Re: HELP! More Rough Idle, Juddering and Rev problems
Right, I've had it up to a local VW/Audi specialist who have all the right computer systems for proper fault code read and diagnosis etc. Including the "official" Audi software.
The car came up with one single fault code related to a lambda sensor, I mentioned that the lambda sensor has already been replaced - but was told there's more than one. So I guess one of them is still faulty?
Anyway, as soon is I rolled into their garage they said two things; "Doesn't sound right" and "Cor, it bl00dy stinks of un-burnt diesel!". I ran through the list of work the cars had done recently, and he said that for it to be over-fueling/stinking like that - it would be either injectors or EGR.
He loosened off the EGR valve and stuck a plate of metal in there to block it off. The engine was still lumpy, but only very slightly and not as bad as it had been - but also NO smell of diesel. Took it out for a drive (approx. 10mins) and I didn't get any of the shuddering and juddering, or hanging on to gears too long etc. BUT these problems come and go at random, so couldn't be 100% sure...
Anyway we got back, he took the plate out of the EGR valve, started it up and it started stinking of un-burnt diesel again straight away. He had caused an EGR flow error to come up by doing this, so cleared down all error codes and checked a load of other things like injection quantities, pressure values, boost, DPF (which, strangely was at 40% which seems high for a new DPF??!) but said for the most part everything checks out OK.
Good news is that I've had a word with my garage and they seem OK with fitting a new EGR valve under warranty. I'm popping down to discuss with the mechanic and service center manager on Wednesday.
However - I've also been advised to have a "proper" custom ECU remap at the same time. Now, the garage I purchased this from - who are covering the car under warranty - said that they brought in a re-mapper to do the car when the new engine went in. But the guy they used is known to the VW/Audi place, and they hadn't heard any good stories about his engine remaps.... :eek: So I'm going to try and get my garage to get a full custom remap through this VW/Audi garage.
If their not willing to cover a full remap as part of the warranty (under the guise of - it should have been done properly in the first place) I may be tempted to pay for it myself (they use Quantum tuning - any experience?) Either way, they said a new EGR valve would need to be registered on the computer system anyway, and considering that my car has had engines in and out, DPFs in and out, and a huge list of other components replaced - it would be worth getting a custom ECU remap done that takes into account the recent history of the vehicle... Thoughts?? :D
I've got from now to Wednesday afternoon to try and gather everything together ready for our "chat" about getting as much of this done as possible under their warranty.
Re: HELP! More Rough Idle, Juddering and Rev problems
I feel bad for you this sounds like a nightmare- when did you buy it?
was the replacement engine in when you bought it or after?
this remap sounds totally rubbish think that has to be the place to start!
something important to remember which someone on this forum recently taught me, just because you don't get a fault code doesn't always mean a component is working!