2003_A4_1.8

2003 A4 B6 1.8t 217k miles.

VIDEO HERE:
Car has super slow acceleration. If you hold throttle to floor it slowly accelerates to 4,000 rpms and shutters and stays at that rpm, if you let off gas it goes into second gear, then hold to floor and takes forever to get to 4,000 rpms in second then let off and it goes to 3rd gear. It takes 20-30 second to get to 50mph?
How do I know if its actually in limp mode or not? How do I reset that?
it had misfired in the past. I have changed all plugs, coils and coil wiring connectors. That fixed the intermittent misfire....Then is was not boosting and I replaced the N95 valve and that fixed the no boost. Then a month later I now have this severe lack of power.... Engine starts easy and idles smooth... I checked fuel pressure and it is 58, so its good. I checked compression and its good... plugs look good....
as for codes, I keep getting misfire codes, but am now thinking it has to do with fuel mix ratio.... Code that is there now but was always there, so i do not think its the issue: <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> 17887 Brake Boost Vacuum System: Mechanical Failure P1479-008.
Most current codes that I think are the issue:
<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--><!--{C}%3C!%2D%2Dtd%20%7Bborder%3A%201px%20solid%20%23 ccc%3B%7Dbr%20%7Bmso-data-placement%3Asame-cell%3B%7D%2D%2D%3E--> 17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 (this comes up right away, would this cause a limp???)
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded (im reading it maybe the DV Valve, would this cause limp?)
<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> 16486 Mass Air Flow Sensor (MAF/G70): Signal too Low P0102 - 002 Lower Limit Exceeded - Intermittent ( newer code, how can I check if this is good, what numbers am I looking for in vcds for grams per second, also short and long fuel trim?)
other things to consider... I have a minor exhaust leak, I have also unplugged the MAF and it drove the same?
Where do a start, what can I test before throwing parts at it? What parts to throw at it first.

5-17-21 since late download date
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
17536 Fuel Trim; Bank 1 (Mult): System too Lean P1128-001 Please reg. - Intermitent Fuel Trim; Bank 1 (Mult): System too Lean
16795 Secondary Air Injection System: Incorrect Flow Detected P0411-002 Please reg. Secondary Air Injection System: Incorrect Flow Detected
5-17-21 quickly comes back afterhard pull
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
5-17-21 after a few mins of driving
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
6-9-21 since last download
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16795 Secondary Air Injection System: Incorrect Flow Detected P0411-002 Please reg. Secondary Air Injection System: Incorrect Flow Detected
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
16712 Knock Sensor 1 (G61): Signal too High P0328-001 Upper Limit Exceeded - Intermitent
16688 Cylinder 4 Misfire Detected
17536 Fuel Trim; Bank 1 (Mult): System too Lean P1128-001 Please reg. - Intermitent Fuel Trim; Bank 1 (Mult): System too Lean
6-9-21 after drive for 10 min
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
6-9-21 after drive for 15min
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16517 Oxygen (Lambda) Sensor B1 S1: Response too Slow
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
6-13-21 since last dl
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16517 Oxygen (Lambda) Sensor B1 S1: Response too Slow
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
6-13-21 last dl same dl
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
6-15-21 since last dl
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
6-15-21 cleared and come back quick
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
6-15-21 cleared and short drive later
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
17700 Map Controlled Engine Cooling Thermostat (f265): open circuit P1292-004 No signal/Comunication - Intermitent
6-22-21 since last dl
17701 ap Controlled Engine Cooling Thermostat (F265): Open Circuit P1292
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16804 Catalyst System: Bank 1: Efficiency below threshold P0420-002 Lower Limit Exceeded - Intermitent Catalyst System; Bank 1: Efficiency Below Threshold
17536 Fuel Trim; Bank 1 (Mult): System too Lean P1128-001 Please reg. - Intermitent Fuel Trim; Bank 1 (Mult): System too Lean
16517 Oxygen (Lambda) Sensor B1 S1: Response too Slow P0133 - 002 Please Register/Activate - Intermittent
16486 Mass Air Flow Sensor (MAF/G70): Signal too Low P0102 - 002 Lower Limit Exceeded - Intermittent
16684 Random/Multipe Cylinder Misfire detected P0300-001 Upper Limit Exceeded Random/Multiple Cylinder Misfire Detected
16686 Cylinder 2 Misfire detected P0302-001 Upper Limit Exceeded Cylinder 2 Misfire Detected
6-22-21 - cleared then 5 min ride
17701 ap Controlled Engine Cooling Thermostat (F265): Open Circuit P1292
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached
16486 Mass Air Flow Sensor (MAF/G70): Signal too Low P0102 - 002 Lower Limit Exceeded - Intermittent
6-22-21 - cleared the comes back soon
17701 ap Controlled Engine Cooling Thermostat (F265): Open Circuit P1292
17887 Brake Boost Vacuum System: Mechanical Failure P1479-008 Implausible signal Brake Boost Vacuum System: Mechanical Failure
16683 Boost Pressure Regulation: Control range not reached P0299-002 Lower limit exceeded Boost Pressure Regulation: Control Range Not Reached

ANY AND ALL HELP GREATLY APPRECIATED, I HAVE SPENTS DOZENS OF HOURS RESEARCHING AND CANNOT FIND ANYTHING?

turbo510

I've never seen such a huge list of fault codes at one time. My guess is something electrical, such as bad grounds or battery + connections. Also, how correct is the cam timing?

2003_A4_1.8

Thank you!, I will check my grounds. how do I check cam timing? As for the codes, its really only 3-8 codes max at any given time. What are your thoughts on me thinking something is happening with the air/fuel?

turbo510

I would next try running with the MAF disconnected, and see if there is an improvement. That would tend to implicate the MAF or wiring. Also, you tach seemed jumpy in the video, kind of weird.

2003_A4_1.8

I have already tried unplugging the MAF, I took it for a drive and it drove the same. But the numbers its reporting seem correct or close. thanks again.

2003_A4_1.8

Update, Checked the DV ( Diverter Valve and its good ), However a minor leak in that area when putting smoke into system. I am cleaning all hoses and fitting and going to snug everything up tight, Also turbine in turbo turns smoothly

2003_A4_1.8

Update, Waste gate actuator working, cleaned up all fittings near turbo and snugged them up... Where to go next? I think I will swap fuel injectors around to see if the misfire moves cylinders. Then I will throw a MAF sensor at it...

Can anyone tell me:
How to know if it is in limp mode? If so how to reset it?
How to test MAF?
How to test Injectors?

Thanks again in advance!

meendds

Have you looked in the box where the ECM/ECU and associated relays are? I have read about lots of issues with water getting in and corroding relays underneath the ECMs that cause multiple codes and the condition you describe of having no power or in limp mode. I am looking at a 2002 with similar problems and debating on taking a chance buying it if price is right. Owner claims it needs ECM issue. If you search youtube there are many videos on water in relay box.

Do you have any updates as to what you have found?

2003_A4_1.8

ISSUE FIXED: The problem was the catalytic converter was bad... I tested the theory by unhooking the cat from the turbo. She ran great! Ordered a new cat. from ebay for $88.88, free shipping. I will do a follow up video, but until then click the video above and read the details in the video description. Good Luck!