Please Help Diagnosing 2000 AWE Stage III Car

B5 S4/ RS4
#1

It’s a Stage III car with the fueling kit with Green Giants. I bought it from my buddy who was not too mechanically inclined. He sold it to me real cheap because it would run like crap when it was cold and would never get full boost. He had taken it to an Audi dealership that said they fixed the problem, $2 grand later and the next day it was doing it again. Well when I got it I figured out the boost problems were a couple of bad vacuum lines and a cracked intake boot. No problem, but I can’t seem to figure out the cold start issue. Here’s a list of what has been done in the past nine months:

Replaced:
APR y-pipe
APR R1 Diverters
O2 sensors (all 4)
EGT Sensor
Coil packs (all 6)
Coolant Temp Sensor
Ignition Control Modules (both)
Spark plugs
MAF sensor
IAT sensor
Fuel Pressure regulator
Fuel Filter
Intercoolers (just for more power)
All intake piping except factory Y-pipe (Samco)
1 Green Giant fuel injector on cyl. #4 (had a broken plastic keeper on the bottom of one)

The issue seems to get worse the colder the outside temp is, or it may just be getting worse period and it just happened to be getting cold also
When I start it cold it will barely run and stumbles all over the place. It smells like it’s running really rich, I can smell fuel. If I shut it off and restart it seems to help, but after a few seconds it will begin stumbling bad again.

After a couple minutes of this it will settle into a stable idle but as soon as I press on the gas a little it stumbles really bad. It will continue to miss and sputter as I drive through the gears until I get above 2000 rpms. Once I get above 2k it starts to boost and it runs fine, but once I come back down it will still do it again. Shifting 1st-2nd is the worst.

The symptoms slowly go away as the car gets warmer and once the car is all the way warmed up it runs like a raped ape (might be faster than my Shelby).

I have a VAGCOM and have looked at all the sensors I know to watch (which I’m sure is not all of them) and everything seems fine. If I really try to push it when it’s still cold it will throw a check engine light but it is just “random multiple misfires”. So it doesn’t tell me shit. I was just wondering if any of you guys in all your car experience have run across this?

Yesterday my “random multiple misfires” code turned into cylinders 1, 3, 5, & 6 pretty consistently. Cylinders 2 & 4 had no misfires at all. I was going to start swapping components from 2 or 4 over to the other cylinders to try to narrow down what is causing the misfire. But now the car won’t even start. It tried a couple times but would just stumble and die. So after towing/pushing up the hill into the garage I pulled the fuel line and was able to confirm that it is getting fuel. I have a psi regulator to install and I may do that later tonight but it doesn’t seem to be a fuel issue unless those four injectors have failed. That only leaves spark or air (MAF, vacuum lines) so I’ll start to look there too. Any help in how to diagnose or ideas for what might be wrong would be greatly appreciated. I’ve searched all over AZ but can’t seem to find anything that fits. This is my first S4 and I’ve only had it for about 9 months so I’m definitely still learning.

#2

You’re Mr Incredible on SVT Performance right? Glad to see you made it over here

#3

its the cold start maps in the tune. The awe tune is very good but the cold start stuff was not teh greatest. Clean your plugs or go get new ones. Don’t start and let the car iddle its only going to make it worse. In cold temps start and run the car right away that will help. Do this for a week come back in and let us know.

#4

Yep, thanks for the advice. I’ll take all the help I can get? ???

I’ll try cleaning the plugs, lord knows I’ve tried everything else.

#5

Isn’t the awe tune a giac tune?

Merlins magic on here works at GIAC.

#6

I have a similar issue when it is very cold, but that is only when running full E85. Since there is no misfire on the cylinder with the new injector, I would try swapping them around. The Green Giants are essentially an on/off injector so there can be some misfire problems when the fuel isn’t fully combusting.

#7

Sir you are a god among men. After pulling the plus I was still not convinced they had enough build-up to be causing my problem. But I cleaned them and checked the gaps (which were all at .028) regapped them to .025-.026 and reinstalled and I’ll be damned if it didn’t start right back up.

I still had misfires and it smells rich as all get out. I didn’t have any more than a dozen misfires on any cylinder until it warmed up and then it was fine. The only cylinder with no misfires is the one with the brand new injector. Time to switch the injector to a different cylinder and see if the misfires move.

If it does turn out to be the injectors, I have heard bad things about the Green Giants. Is there another set with better reliability that I can change out to without a retune?

#8

I had the same AWE stg 3 when I purchased my car. It actually was a clogged green injector that gave me weird cold start issues and an off normal idle with occasional blips. Since moving to a different tune with new injectors, my problem is gone. If you aren’t in the market for a new fueling setup, I’d pull the injectors and send them out to be flow tested just to make sure as it didn’t seem you did that per your first post.

#9

If you don’t want to retune the fix is get a heat range hotter plug. In the winter never let the car sit idle when. You first start it don’t let it sit just turn the car on and go. Make sure to getthe car upto operating temps to clean off ghe plugs. If you do that your going to be Good to go