03' A4 1.8t AMB 15psi stock?? Boost surge?

[B6Sticks]

I'm having a weird issue with my 03' 1.8t quattro 5 speed. AMB 1.8t. Or lack of problem I guess you could say. I'm the second owner, the first owner was an old guy, so I really don't see how the car could be chipped. But i push 14-16psi when it initially spools at 3k rpm and then after around 4500 rpm it settles around 12psi. (where it should be, 11-12). And then it drops off closer to redline as would be expected with the stock ko3. My boost gauge is accurate, I compared it to live data on the car, and the cars requested and actual boost are within 100mbar from eachother, and no lean codes or anything. I only have one intermittent code for the cat, but as it's original with 136k on the car I know it's getting to the end of its life span, but I don't think that would cause this. If I boost and hold it at 11-12psi, like 85% throttle, it feels quick and how stock power should feel. Then I push the pedal the remainder to the floor and it boosts to 15psi and holds, and doesn't rly feel any faster. I know with 15-16psi on a tune it would be around 200hp and it's definitely not pushing that much hp. The boost comes on totally smooth and holds, no jumping around. Like the car runs perfect, except that it pushes 15psi and does not feel tuned, so I think it's an overboost condition. Never been in limp mode or anything, which I thought occurred after 13psi on a stock tune. I unplugged the n75 and the car pushes 3-4psi so I know the wastegate on the turbo is good. The turbo has a slight whistle sound, but not like a dentist drill, it boosts perfect. More sounds like a boost leak, but since I put the boost gauge in 3-4k miles ago, it always has done the same thing, consistently pushing 15psi, then after 4500 rpm tapers to 12psi where it should be. I know it should surge to 12 or 13psi max and settle around 11. I've inspected all the turbo piping and vacuum lines and all look fine. Also the car has perfect vacuum at -21 at idle. No vacuum leaks. Silky smooth idle. The car is perfect besides pushing more boost than it should and not feeling any faster like it's tuned. I've thought maybe n75 valve is faulty, but the boost is so smooth and always consistent. I don't wanna spend $80 for a part that is most likely fine. Any ideas?

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[dalazybastard]

Given that your requested vs actual is very close. I hate to break the news to you... you may be tuned.



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[B6Sticks]

Given that your requested vs actual is very close. I hate to break the news to you... you may be tuned.



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Thanks for the quick reply, that would make sense as it's asking for what it's making. That didn't click with me before! I will recheck that tomorrow to make sure it's asking for the full 15-16psi. It just doesn't feel as fast as it should running that boost, or maybe I'm just used to it. But I've driven another stock b6 1.8t quattro and mine feels the same. So that's why I'm confused. I was planning to go apr stage 1 this summer. And then 1+ after injectors. I wish I could see of my ecu has a tune on it somehow.

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[dalazybastard]

15psi should be around 2000-2100 mmbar.

A stock 1.8t requests around 1500mmbar

If you did have apr software right now, you could see if you can cycle the tunes with the cruise control stalk.




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[B6Sticks]

Yes it was requesting at least 2000 mbar for sure, and making 2100-2150mbar. I actually tried that, when I hold the stalk, the engine / esp light both flash once. And that's it. So I don't know what that means, but it wasn't apr's switching.

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[walky_talky20]

^On a stock car, nothing flashes when you do that. So I'm guessing it's APR software with only 1 program on it. Or it's locked out of mode-switching by security PIN. I forget exactly how those act when they are locked.

[B6Sticks]

Yeah I was thinking about the security pin. Maybe I'll get ahold of the previous owner and see if he had the dealer do it for him. The guy was probably in his 40s when he bought the car brand new in 2002, so maybe he wanted more and had a dealer or shop give it a stage 1. Also I checked and the injectors are stock, so it's definitely not 1+, and the boost points to just a stage 1 as well. So im not sure if it would have multiple programs if it has original injectors. But he didn't say anything about a tune when he sold it to me. Maybe I'll call apr and see what they think about the single flash only when stalk is held. And Ill see how apr could check if the car is tuned if I can't get ahold of the previous owner.

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[Ephry73]

Are we sure it is APR software? The injectors may have been swapped for stock ones or something, it's not unlikely. Definitely sounds like a tuned ECU. Check the intercooler and see if it is the stock one as well. maybe you could spend the time and money on a better bigger unit and see how she goes. I'm pretty happy with Motoza tuning and they have a great upgrade program as well. Super smooth and progressive.

[B6Sticks]

Intercooler is original, checked when I did my timing belt and water pump and had the bumper off. That's what I'm wondering too, if it's not APR. When holding the stalk the engine light and ESP blinks once so my thought is it's APR and telling me it's just one program, stage 1.

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[B6Sticks]

UPDATE: Got ahold of the previous owner. The car was chipped. He doesn't remember what brand chip, but he gave me the number to the shop where he thinks did the chip for him. When I replaced my wiper transmission I noticed the ecu looked scratched up, like someone has been there. What I'm trying to figure out now is, what brand chip do I have, and is it a physical chip, or a flash tune. The shop he told me is a smaller shop, but has been an audi/vw tuning shop since 1999. I'll call them tomorrow to see if they have a record of my car. They are not an authorized dealer of APR, GIAC, UNITRONICS, or REVO. At least that's what the websites say. I'm very very curious. The car pushes 16psi average and I'd like to go stage 1+ with Audi tt225 injectors. But if it's a physical chip I'll have to get it removed and then flashed. In really hoping the car was flashed and not actually chipped. Any thoughts guys?

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[old guy]

If you have a physical chip you will probably have to purchase a blank chip to be programmed. I chipped my 2003 A4 at 1,200 miles and the flash technology wasn't out yet. Fortunately I kept the OEM chip. Several years later I went with the GIAC big injector file and AWE had to reinstall the OEM chip so they could flash the new program. If I recall a blank chip was only around $50 at that time. You can open up your ECM and check to see if the physical chip was replaced. Your first indication will be slots cut in the tamper proof securing bolts on the ECM hold down strap.

[B6Sticks]

If you have a physical chip you will probably have to purchase a blank chip to be programmed. I chipped my 2003 A4 at 1,200 miles and the flash technology wasn't out yet. Fortunately I kept the OEM chip. Several years later I went with the GIAC big injector file and AWE had to reinstall the OEM chip so they could flash the new program. If I recall a blank chip was only around $50 at that time. You can open up your ECM and check to see if the physical chip was replaced. Your first indication will be slots cut in the tamper proof securing bolts on the ECM hold down strap.

Thanks!! I'll see what the shop says tomorrow that supposedly did the work, and if they don't have an answer I'll open the ecu box back up and inspect it carefully. When I did my wipers the metal band that holds the ecu down came right off with a flathead, prying one of the ends. The ecu was scratched up but I didn't look at the underside of it or wherever the screws are.

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[Kevin C]

You can always buy a spare ECU and clone the SKC so that you have a drop in spare that can be flashed.

[B6Sticks]

UPDATE: car is APR stage 1. Has a real chip, but to go APR 1+ injector file they flash over the chip. Excited I got it figured out! Thanks for the help guys.

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[Ephry73]

Awesome!!!


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[texasboy21]

UPDATE: car is APR stage 1. Has a real chip, but to go APR 1+ injector file they flash over the chip. Excited I got it figured out! Thanks for the help guys.

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Awesome! Its nice to see issues like this get sorted out. Time for the APR big injector file! Its a lot of fun, and how the car should have come from the factory.

One thing to mention however, to get the most out of the big injector tune you need the basic supporting mods - quality FMIC, high-flow cat or testpipe (a downpipe would be nice too, its a good bump in the middle of the rev range), high flow filter in the stock air box (a turbo inlet pipe is also a good idea), and a functioning divertor valve.

[B6Sticks]

Awesome! Its nice to see issues like this get sorted out. Time for the APR big injector file! Its a lot of fun, and how the car should have come from the factory.

One thing to mention however, to get the most out of the big injector tune you need the basic supporting mods - quality FMIC, high-flow cat or testpipe (a downpipe would be nice too, its a good bump in the middle of the rev range), high flow filter in the stock air box (a turbo inlet pipe is also a good idea), and a functioning divertor valve.

I'm one step ahead of you! I already put in a 710N DV, I have a new stock air filter, but I smoothed my airbox, and I'm gonna be getting a 034 high flow cat soon. And when my flex joint breaks a TT tuning 2.5 down pipe. I'll def have the high flow cat before the tune! I've been doing tons of other maintenance on the car as well, runs like new!

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[B6Sticks]

Quick update, just installed a 034 HFC! Car sounds a little better, and 1st gear definitely feels more peppy. 2nd gear in boost till around 45mph feels the same, but I've only driven around town for a few minutes since the install. I'm guessing the car has to learn the new cat as I drive it more. Can't wait to see the difference it makes on the highway.

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[B6Sticks]

Made a video comparison of the sound difference! https://youtu.be/dQJCrLKgBHs

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[B6Sticks]

UPDATE: this should be the last one to put the thread to bed. I was getting sputtering in boost after the HFC install, but no misfires detected, and even before the install the care never felt as fast as it should. I tested the N75 and warm and cold it reads 30ohms and it doesn't let me blow through the long tube on it so I know that's good. I figured out I was getting spark plug blow out. I got some denso iridium plugs, gapped them to .029 (I saw people saying from .028-.030 for my modification level), and put them in. WOW. The car pulls so hard and the shove in second gear from 40-60 really puts you in the seat. Holds 16psi constant and makes the power it should be. The old plugs were JUNK. They were so worn and fouled and read .060 gap!! That's pretty much twice the OEM. The car is so fun now and runs like a dream. Can't wait to get injectors and go stage 1+!

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[Ephry73]

So glad to hear it man!!!


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