S4 Vert

Ok, thank you.

I will study the wiring diagrams and see if I can locate the EM-19, F-49, and EM-14 parts in the engine compartment. I will see what needs to be done and get at it.

S4 Vert

After going back to the S4 NA to turbo link in the body of your post, I read the Boost sensor paragraph.

"BOOST SENSOR: Get a Turbo II boost sensor #318. If for some reason you don't have one by the time you are going to fire her up you can do two things: (And I know its not right guys so don't flame me for saying these things...) 1. leave your NA boost sensor in and just don't hit boost until you get one. If you do it will boost up but will stutter really bad unless you floor it then it will accelerate sorta normally. I'm not sure if it runs lean or rich when you floor it so just don't do it unless you Really have to. 2. Unplug it completely. The ECU will set the Boost sensor parameters at a preset level and leave it there (sorta like S4 limp mode kinda). With it unplugged you can drive the car normally but it will run rich (bad gas mileage) and your "shift up" light won't work. I know it runs the engine rich because I checked the stoich (Air to fuel) level with my Wide band meter on one of my TII's when I unplugged the boost sensor. (again flame on if you think I'm wrong, this is just a temporary suggestion guys there's no substitute for a real turbo boost sensor)"

I'm thinking maybe the boost sensor I have is not the correct unit. It does have a N318 sticker on it, however the sticker is clean and looks like it could have been glued on. And my up shift light does not light up from 1st-4th gear buy in 5th gear it does. The engine does kind of stutter alittle and does not boost hard unless I mash the gas pedal had, but that only happens in 2nd gear.

I'll look into the boost sensor some more, before I say that is the problem. That paragraph really clicks with what my engine is doing, besides the shift light coming on while driving in 5th gear.

RotaryRocket88

iTrader: (7)

Test output voltage at ECU pin 2B w/ the vacuum line off of the boost sensor.

NA: 3.5-4.0V
TII: 2.3-2.7V

S4 Vert

Will do.

Thank you for the advice.

S4 Vert

Is there a difference between the na and turbo II variable resistors? I kept my na variable resistor and have not made any adjustments. Could that be the reason I am not getting full boost?

I noticed that on na FC's there is a air bypass relay and on the turbo II models there is a air bypass solenoid valve. Should I disconnect the na air bypass relay?

I also noticed that both models have atmospheric pressure sensors. Is there a difference between the two? I think I may have confused the pressure sensor (I also called it a boost sensor in my previous post, doh!) with the atmospheric pressure sensor and installed it in the wrong location. I have a N318 unit and now I'm not sure if I should install it where the atmospheric pressure sensor goes instead of in place of the pressure sensor.

I think this is where and why I'm having boost issues. Even after completing my swap I am still learning. Details details.

RotaryRocket88

iTrader: (7)

No

ASV takes over some of the BAC functions carried on on an NA. Some stuff is still done by the BAC. Plus the BAC has the bypass screw to set idle speed.

MAP/boost sensor goes under the hood on the strut tower. Atmospheric sensor goes inside the car and is the same for NA and TII.

S4 Vert

Ah! Ok, so I am doing ok then. I thought maybe I might have mixed up the two, I do have the N318 pressure sensor installed on the strut tower and the vacuum hose from it running to the air control valve.

I will have my vert hooked up to a dyno to run some pulls to check the boost, air and fuel ratios. I really do not know how well the engine is running, it drives ok, but still feels like it's running na more then boosted and drinks a lot of gas on conservative driving. I'm using almost a half a tank of gas to travel ten miles.

S4 Vert

Found out what the boost problem was, the turbo to manifold gasket was blown, and the turbo inlet pipe was cracked at the turbo inlet. I had those problems fixed, I'm getting some boost but still not full boost. I'm performing a compression test/check tomorrow to see where the compression is. If all is well with the compression, next is emissions parts removal (block off plates kit), new vacuum hose spider, and idle adjustments. Hopefully those repairs will get me the boost I'm looking for.