I’m in the middle of a diagnostic project on my RS4 and I need to pull up my long term fuel trim info/history via my vagcom cable & VCDS spftware. I did search the Ross Tech’s site Wiki page and found an answer:
I must be an idiot because I’m having a hard time finding that particulat group and i’d like some help from you guys. I have logged various attributes on the car and now I’m looking to review my LTFT history to help diagnose a possible hardware issue. Basically I’m running rich and I need to narrow down the possibilities.
If anyone can provide the step by step (I should say screen by screen) instructions on how I can achieve this retrieval I’d appreciate it. I haven’t used the cable in so long I have forgotten a lot of what I had picked up along the way when I first got it. I somehow also lost all of my cheat sheets which sucks…
your looking for a value. The LTFT is not something your going to log but something your going to view and make note of.
Here is how get there.
open controller
go to the
select control module and hit select.
then goto 01 motor or engine
I would check fault codes first. DON’T clear them if there are any just record them
Then goto measuring blocks and select 032. This will give you 4 windows of information. Copy that and then post it here.
If this was not complete enough let me know. I can add more to help.
Thanks - yes, i remembered it would be a value, I think there will be two columns, both are percentages according to the Ross Tech wiki. One for idle and one for upper RPM’s (02’s vs. MAF essentially)
I did check for fault codes yesterday and there were none. Thanks for the reminder, I won’t be clearing any of them.
Damn, that’s what I thought I did yesterday but couldn’t find 032 while in measuring blocks, under the category 01 engine. I’m going to check again when I step out for lunch.
Thanks for taking the time to respond. I’ll post my finding here.
My dumbass finally found 032 - I think I was clicking past it too fast for the data to pop up and I though it was an empty number…stupid on my part.
Results:
Idle = -3.1%
Partial = 5.9%
If my math is correct, those are way out of the “normal” 10% difference normally allowed. I would think I should have seen a CEL by now…right? All help is much appreciated.
The delta is more the 10% but the actual values are good. You will get a CEL when you reach 18% off one way or another.
My S5 has values of
-.7 __ 8.8 __ -2.1 __ 5.3
The negitive ones are iddle and the positive ones are part throttle. So its a little rich at iddle and a little lean part throttle so its adding fuel to keep up
Thanks for chiming in, I received the same good news from a very good guy who is taking the time to help me navigate this process.
Learned that 18% figure here too - I was under the impression anything past 10% would trigger it. Again good info on this site.
Here is a little back ground to catch everyone up. My other thread regarding the smoke exiting my tail pipes ended up being leaking valve guides. That smoke was a blue/grey color 90% of the time. Sometimes it looked more black. Fast forward my warranty company replaced the following parts; heads, I/M, PVC valve and some of the breather tubes, drivers side valve cover, passenger side cam follower cover (updated version), spark plugs, oil change and all of the other filters/fluids etc. Great, now the car feels solid.
After about 150 miles of carbon free driving, I noticed that once I was up to operating temps (oil is 170+) I would see a puff of blackish looking smoke with a little bit of blue in it. This only happens once I’m stopped at a traffic light for more than 45 seconds…sitting there at idle…then when I take off, (slowly or quick doesn’t matter), I get a small plume of smoke. I’m thinking to myself, blue is usually oil and black is usually carbon. I’m confused at this point because I know I am 100% carbon free and my rings and bottom end was solid when we inspected everything while the heads were off. Compression test was aces across all 8 cylinders and the leak down test pointed to the valves and that’s it.
I was thinking a few things, either one of more of my injectors were leaking (but that would mean the O2’s would pick up on it and tell the ECU’s which would compensate) or I had another item that is failing; i.e., ECU’s, o2’s, MAF etc. So I inquired here on AR to remind me how to look up certain values like LTFT and log through various RPM’s to monitor other potential factors.
Now that I have confirmed my LTFT values are within spec that leads me to believe that the O2’s, MAF and ECU’s are all doing their job….yet I still have this smoke coming out when taking off after an idle of 45 seconds or more when the car is warmed up. Then I was told maybe it is the PCV system. I did have certain parts replaced but maybe it is still pulling and dumping oil - most noticeable while at idle or slowly pulling away because there is no air moving past the car to break it apart etc.
I’m trying to have someone follow me with a vid recorder so I can share it here and with my dealer. I did take a tech for a ride and he did get a chance to witness the plume of smoke but he was convince it was fuel, was running rich and I had a tune…no willingness to scan or look into it or anything like that. This dealership is really all about turn and churn, if it’s a third party warranty company job they don’t want to do it because they can’t get paid what they want. Anything that is tricky diagnostic wise they shy away from because they don’t get paid enough or lack the skill set – I don’t know. Either way it’s frustrating to me so I’m trying to narrow the possibilities down, prove my theories to them and then have them verify my findings and address the issue(s) once and for all.
Thanks everyone for the continued support. I’m a f’ing sales/entrepreneur guy at heart, not a certified tech yet some of the BS that comes out of the techs/service peoples mouths at this particular dealer can be mind numbing at times.
as for the smoke, after sitting overnight, what’s it like when you start it up? That’d be good to see…then you can see the smoke yourself and make a video while someone starts the car.
Performance = ;D Pulls like a train. logged a few 3rd gear pulls from 3K-8K. avg was around 8 flat.
Used to have that issue with the old heads. Thankfully I’ve checked for that many mornings since my new parts were installed with my flip recorder on the ground behind my car and once with my wife starting it, no issues.
I have a new idea - cyclonic oil seperator. After refreshing myself by rereading the RS4’s self study PDF I have surmised this is a very possible culprit. Now all I need to do is figure out how to test if it is functioning properly. Any ideas guys?
I and Im sure others will agree with this being the most plausible issue. Ive seen this be the bug on a few RS4’s now. Im looking for something to help show you more on how to investigate this
^Good to know. Any chance of getting a copy of the TSB on here? I’d like to see/read how they recommend cleaning and what areas to lube. I’ll do this myself instead of trying to convince my dealer. Hell, a little bit of time on my end and even if it’s not the cause of the issue I’ll have, clean parts, and I’d have ruled out another potential culprit. Win win to me.
