[Treg_2112]

Hello,

New to the forums and looking for some input from the engine gurus. This topic may have been covered here but I am considering a purchase of a 2008 V8 with >100k. The price is quite reasonable as the idle is pretty rough. Once moving it smooths out and seems to run just fine. From what I have read this could be everything from coil packs, fuel pump, timing chain issues?

I have been a loyal VW/Audi owner for years, never any experience with this engine. I was able to hook up the VAG COM and scan codes. Will include those in another post. Is this thing worth considering or should I run the other way? I would be comfortable putting 2-3k to get this thing up to par but obviously don't want to lose my tail on it either. Any thoughts?

 

[Treg_2112]

20 Faults Found:
008852 - Fuel Pressure Regulator Valve (N276)
P2294 - 004 - Open Circuit - Intermittent - MIL ON

004763 - Fuel Pressure Regulator Valve; Bank 2 (N276)
P129B - 004 - Open Circuit - Intermittent - MIL ON

005170 - Secondary Air Injection Solenoid Valve (N112)
P1432 - 004 - Open Circuit - MIL ON

005253 - Secondary Air Injection Valve 2 (N320)
P1485 - 004 - Open Circuit - MIL ON

000023 - Bank 1: CMP Sensor 3 (G300) / Engine Speed Sens (G28)
P0017 - 002 - Incorrect Correlation - MIL ON

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - MIL ON

000772 - Cylinder 4
P0304 - 001 - Misfire Detected - MIL ON

000776 - Cylinder 8
P0308 - 001 - Misfire Detected - Intermittent - MIL ON

000774 - Cylinder 6
P0306 - 001 - Misfire Detected - Intermittent - MIL ON

000773 - Cylinder 5
P0305 - 002 - Misfire Detected - Intermittent - MIL ON

000258 - Mass Air Flow Sensor (G70)
P0102 - 002 - Signal too Low - Intermittent
Voltage: 12.319 V

000268 - Mass Air Flow Sensor (G246)
P010C - 002 - Signal too Low - Intermittent
Voltage: 12.319 V

005173 - Secondary Air Pump Relay (J299)
P1435 - 002 - Short to Ground - Intermittent - MIL ON
Voltage: 12.319 V

000049 - Oxygen (Lambda) Sensor B1 S1: Heating Circuit
P0031 - 002 - Short to Ground - Intermittent
Voltage: 13.716 V

000081 - Oxygen (Lambda) Sensor B2 S1: Heating Circuit
P0051 - 002 - Short to Ground - Intermittent

009217 - EVAP Leak Detection Pump Control Circuit
P2401 - 002 - Short to GND - Intermittent
Voltage: 13.843 V

000775 - Cylinder 7
P0307 - 002 - Misfire Detected - Intermittent - MIL ON

000055 - Oxygen (Lambda) Sensor B1 S2: Heating Circuit
P0037 - 002 - Short to Ground - Intermittent

000771 - Cylinder 3
P0303 - 001 - Misfire Detected - MIL ON

000087 - Oxygen (Lambda) Sensor B2 S2: Heating Circuit
P0057 - 002 - Short to Ground - Intermittent

 

[noobytoogy]

Run.

 

[Grifnsqest]

Quite a few short to ground errors. Look into frayed wires/connections first.

 

[Treg_2112]

Would a ground issue cause the idle alone to run rough?

At this point the number of sensors etc don't scare me much...maybe I'm wrong here...My concern would be whether or not the idle is something intensive/destructive like timing chain issues or fuel injectors that would be a major immediate overhaul. Just not sure if these code patterns fit or something if there is a better way to tell?

Thanks for the input.

 

[Grifnsqest]

Anytime the ECU isn't happy, the potential is there for the motor to not be happy either. So yes, a bad ground somewhere could be the source of all your issues. It could also be 1 out of a 100 other reason too. But, in order to get to the bottom of it, and properly diagnose your issue, solve your ECU issues first.

Try not to assume the worst, like timing components or injectors. Start with the obvious...

 

[nickyt]

You need to check for a vacuum leak first, bet you have at least two.

Once the vacuum leaks are fixed, clear codes and test again. See what, if any codes remain. Start fixing from that point.

Also assume that you will need to decarbonize the FSI engine. A good one to two day project.

Rules:
If you want zero/low problems, run.
If you can get it for the right price and like to tinker... you will have your project card filled for the next 3 months.

 

[N_Jay]

Fix the sensor/electrical issues first.
You can debug other problems when you still have open shorted sensors and controls.

If it started running bad all at once, it is probably a single or set of related problems.
Mechanical stuff would not show up as shorts and opens.

Look for rodent damage or poorly done repairs to the wiring.

 

[noobytoogy]

This thread is a year old!