Turbo lag, high measured boost at idle

[lug_wrench]

Hi Folks,
Long time lurker, first time poster. Not finding what I'm looking for with search.

2006 A4, 2.0T, 125k miles. I've had it for 6 months and have slowly been fixing problems. Had a misfire on #3 and fixed that with an intake clean and new injectors. Also fixed a bunch of oil leaks.

Problem: When I stomp on it, it doesn't do much for a second or 2 and then takes off. My 0-60 is over 10 sec! I replaced the DV which was already the new version. This made no change.

Just got an OBDEleven and checked channel 115-3,4. My measured boost at idle is super high (~13 psi) compared to other graphs I've seen posted. The measured boost lag can really be seen on the graph below. This is idle to WOT.



Any ideas what I've got going on? Bad or dirty MAP? Anything else it could be or I should check?

Thanks.

[EvolutionArmory]

You shouldn’t have ANY boost at idle. If you’re seeing a value at idle you are probably seeing the MAP sensor sensing atmospheric pressure which should be about 900-1030 mbar.

[EvolutionArmory]

Your graph doesn’t show.

Your logs at idle don’t mean anything. When you log boost you log in second or 3rd gear and you log from 1500rpms to redline.

This is what a boost graph should look like.


Blue is requested. Red is actual.

[EvolutionArmory]

And FYI, atmospheric pressure is about 14 PSI 😀

[lug_wrench]

Hey, thanks for your reply. What your're saying about atmospheric makes sense. I'm at 4000' so 12.5psi is pretty much right on.

I'll try to make a new boost graph like you noted tomorrow, in the meantime, here's another attempt at getting my 1st image to show.



Let me know if you can tell anything from it? Thanks.

[lug_wrench]

Forgot to mention.. No codes. Just sloooow.

[EvolutionArmory]

Log the data from the rpm’s I told you to and make sure you DO NOT let off the gas. FULL THROTTLE from 1500 to redline (6800-7000 rpms). 3rd gear is better but if you can’t do it safely, do 2nd gear. The car will be slow from 1500 to 2500 in such a high gear. That’s normal because you don’t really make full boost until 25-2800 rpms.

[lug_wrench]

Here's what I came up with this morning. Let me know if you see anything. Thanks.

[EvolutionArmory]

Looks normal.

You see that huge gap in the beginning of both of our logs? That’s your turbo spooling up. You should have normal turbo lag below 2500 rpms. Maybe even a little higher. My car reaches full boost at 2800 rpms.

[lug_wrench]

OK. That's good to know.

Any ideas what might make my 0-60mph so slow? Over 10 sec. It's like when you stomp on it, it just doesn't do anything for a second before taking off. If you only apply a moderate amount of throttle it seems to grab and go better, but still ends up with a slow 0-60.

[EvolutionArmory]

I have no idea what tool you are using to measure it and how accurate it is.

[al3k]

OK. That's good to know.

Any ideas what might make my 0-60mph so slow? Over 10 sec. It's like when you stomp on it, it just doesn't do anything for a second before taking off. If you only apply a moderate amount of throttle it seems to grab and go better, but still ends up with a slow 0-60.

You could also log your throttle position sensor (TPS) to see if it fully opens once you stomp it, maybe its sticking or something (never heard about it before tho).
Log MAF to see if it meassuring, about 3-4g/s at idle and upto 180g/s if its stock or 200++ at redline if its tuned.
could also check and log the meassured lambda to see if something funny with air fuel ratio is going on.
it probably is something else but just throwing some stuff out there.

[EvolutionArmory]

Block 60 is a better way to judge throttle body health. Both values should equal roughly 100% combined at all times.

[lug_wrench]

I'll try measuring some of those items and report back. I've just been using a stopwatch for my 0-60. Looks like I can do better tracking that with OBDEleven. I'll see if I can get more accurate with that as well. Thanks.

[EvolutionArmory]

You drive a 200 HP 36-3800 pound tank that can’t get out of its way fast enough stock. How fast do you think it should be?

Stop trying to find problems where there aren’t any 😀

[AudiKilla]

Are you stock or tuned?

Could also be the hot weather, timing pull, fueling problem, etc. need to log all these things.

[AudiKilla]

If you log with your obdeleven, get the csv file and drag n drop onto “malonetuning.com” website. It should make it a proper graph for you.

[lug_wrench]

Thanks for the things to check. Going to be a few days before I can mess with it again. I'll get back then with more details.

[lug_wrench]

Hey Folks, Finally getting back and wanted to post what fixed my issue just incase it helps someone else. Like EvolutionArmy said it is a tank and nothing was really wrong with it - sort of.

I did 3 things at once and my slow out of the blocks problem seems to be fixed. Not scientific I know cause I'm not sure which one did the trick.
- Aligned the throttle body with OBDEleven - https://www.youtube.com/watch?v=cYG2gOWW1zQ
- Reset the kick-down. Here's the vagcom procedure - OBDEleven worked the same. http://wiki.ross-tech.com/wiki/index...Basic_Settings
- Reset the transmission ecu - https://www.youcanic.com/guide/audi-...eset-procedure

She takes off like a scalded cat now and my 0-60 is at least 2 sec faster. And no, I never accurately logged it before or after.

Thanks all for your help. The TB logging suggestion is what got me pointed in this direction.

Now if I could just get my pesky low oil sensor light to go away, this thing will be running great! Until the next thing breaks (hey it is an Audi with 125k miles, I should expect it).

Cheers!

[EvolutionArmory]

Your 0-60 app might not be 100% accurate but it will tell you if your car is going slower or faster than it was compared to your old data at least.

[dalmation53]

You drive a 200 HP 36-3800 pound tank that can’t get out of its way fast enough stock. How fast do you think it should be?

Stop trying to find problems where there aren’t any

Lol he said tank... This car is heavy as hell indeed.

Sent from my G3313 using Audizine mobile app

[TWiST]

I have a 2007 TIP, have had it since new and its got about 186k on it. I have noticed that giving it a little gas and then slamming it down has always been faster then just slamming it down, not sure why that is, but its basically been that way since I got it new. You can also 2 foot to build a little boost and then let off the brake, not great for the torque converter but that is a different discussion.