[Ecca]

Hi Guys. I have a 2008 R50. I have only recently purchased the car and it was fantastic until now. Engine is running on 5 cylinders, RH bank only. It happened on startup. Park the car it was fine, tried to use the car some weeks later and the problem occurred. My first thought was an air flow meter. Checked it out with my multi meter and all is good. I was a bit lost then so I Purchased the vag-com system from Rosstech. All checks out good on Vag-com. I have a bass speaker out and a steering angle issue. When I do a diagnosis with the engine running I only get random misfire error. I have had a look at the voltages with the engine running and I think all is good. Now I am thinking a wiring fault. Maybe the power feed to the injectors on one bank?? I am hoping there is a fuse or something for that side of the engine.
Any ideas anyone? Does anyone have a wiring diagram for the engine.

Thanks for the help

 

[lgibson]

Will VCDS "talk to" address 11? Do you have rodents? Post a complete auto-scan. Ross-tech forum requires this for help. You may want to go directly there.

 

[schootsie]

Are you sure you scanned both banks? They are completely seperate on the VCDS scan as there are 2 ECUs. John

 

[dragline1570]

Are you sure you scanned both banks? They are completely seperate on the VCDS scan as there are 2 ECUs. John

Yes John I find it funny that with that sort of issue the car doesn't throw any indication code??




regards
Drag

 

[Ecca]

Are you sure you scanned both banks? They are completely seperate on the VCDS scan as there are 2 ECUs. John

Can you explain address 11 to me? I did a a auto scan with the VCDS. I will get a scan and post it. Yes I live on a farm and my wifes car some years back had rodent damage. I cannot see any damage/evidence. Is there a place I should look.

 

[Ecca]

Hi John. Thanks for your help with this problem. I am still learning the VCDS so any advice is appreciated. I did a auto scan that I thought checked everything. When I looked at the voltages I could see 2 air flow voltages, 2 boost pressures etc. I think I am talking to both ECUs.
Let me explain the how I think it is on 1 bank. While running if I stick my hand under the car and touch the exhaust the RH side is hot and the LH is cold. If I squash the intake rubber hose, both sides will suck in. So both banks are turning pistons and camshafts. Engine sounds laboring while running. If you use any throttle your can hear the turbo spooling up. Watching this on the VCDS you can see the MAP pressure rising on one bank more than the other. The above observation has made me think it is only fueling one bank. Thinking more about the problem I think it has done a similar thing before. I noticed poor running once before. I shut down and re started and all was good. Your thoughts will be much appreciated.
Regards Eric

 

[dragline1570]

Hi John. Thanks for your help with this problem. I am still learning the VCDS so any advice is appreciated. I did a auto scan that I thought checked everything. When I looked at the voltages I could see 2 air flow voltages, 2 boost pressures etc. I think I am talking to both ECUs.
Let me explain the how I think it is on 1 bank. While running if I stick my hand under the car and touch the exhaust the RH side is hot and the LH is cold. If I squash the intake rubber hose, both sides will suck in. So both banks are turning pistons and camshafts. Engine sounds laboring while running. If you use any throttle your can hear the turbo spooling up. Watching this on the VCDS you can see the MAP pressure rising on one bank more than the other. The above observation has made me think it is only fueling one bank. Thinking more about the problem I think it has done a similar thing before. I noticed poor running once before. I shut down and re started and all was good. Your thoughts will be much appreciated.
Regards Eric

Yes Eric post a full scan




Regards
Drag

 

[Ecca]

I have attached the scan (I hope) I know this is not the correct section but it is relating to this thread) This scan was done with the car running. If I clear the dtc there is no fault seen in the vcds until the engine runs. Then all I can see is a misfire. Any help appreciated.

 

[FSJ Guy]

The header shows all your modules, but the detailed listing is not below.

????


There should be more. It appears cut off below Address 02.

 

[Ecca]

Sorry try this one.

 

[4ePikanini]

Scan engine 2 as well.

Sent from my Hisense C20 using Tapatalk

 

[Ecca]

How do you scan engine 2?? I cannot see this feature in the Ross tech Vcds. I thought an auto scan did the lot??

 

[dragline1570]

How do you scan engine 2?? I cannot see this feature in the Ross tech Vcds. I thought an auto scan did the lot??

You scanned engine 2 when you did the auto scan (labelled Engine II ).
Your issue is on cylinder's 1-5 the RHS bank. Engine.
I can think of a few possible causes but probably not limited to this.


- Tandem pump some how is not developing the required 110 psi that is required to feed the injectors.
I have seen this happen but the car still ran better than on 5 cylinders?? Issue is that the V10 engine does not monitor fuel pressure in any form so the ECU would not know that low pressure was causing the misfire from improper injection. This sort of lines up as the other bank has its own fuel pump.


- Damage/failure of the RHS injector harness. You should be able to check the injectors thru measuring blocks or values? I should have the numbers that you look at some where I will look and post if I can find them. Still if this was an issue I think you would get more than random misfire??


- Master (RHS) ECU has an issue but again this would present as a communication issue I would think?


regards
Drag




-

 

[Ecca]

Thanks Drag
Issue is the LH , passenger side of the engine. I cannot be sure all are not firing. In my searching I have see there are pumps on the end of each head. I am thinking more electrical as the first time it did a similar thing it came good after a restart. I would like to check the power feed to the injectors. Not sure how it runs on the treg. Most cars have a constant power feed to the injectors and the ECU grounds the injectors to fire them. Is the treg the same? Do you know where the power feed comes from? Any fuses? Do you have wiring info for what I am talking of? Another reason I am thinking a short circuit as it appears the battery is going flat. I am in a process of measuring the voltage drop. Not sure if it me playing around with the car or there is a problem. I will recheck the voltage in the morning.
Is there any way of seeing the injector duty cycle while its running via the vag com?
I have seen the output test on the vag com. I was little scared in this section so I did not look too hard but can I test the injectors and pulse them.
Thank you very much for your advice.

 

[IBrad]

Ecca


Fault code 768 / PO300. from the list on RossTech


16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected
Possible Causes

• Air Intake System leaking
• Fuel Supply faulty
• Injector(s) faulty
• Ignition Cable(s) and/or Spark Plug(s) faulty
• Ignition Coil(s) faulty
• Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
• Camshaft Position Sensor (G40) faulty

Possible Solutions

• Check Misfire Recognition
• Check Air Intake System
• Check Fuel Supply
• Check Injector(s) and Injector Sealing
• Check Ignition Cable(s) and Spark Plug(s)
• Check Ignition Coil(s)
• Check Exhaust Gas Recirculation (EGR) Valve (N18)
• Check Camshaft Position Sensor (G40)

hope something in this list helps.


Ian

 

[IBrad]

Ecca


also have a look at this link, if nothing else it will give you a good insight into some of what goes on inside your engine.


I would have a look at the EGR valve N18 (don't know why smiley faces appeared in that post.)


how much does the engine vibrate when running like it is?


http://www.olaf-jacobs.nl/downloads/SSP/SSP_304-1.pdf


Ian

 

[Ecca]

Hi Ian. thanks for the link I will check it out. Engine runs OK considering. Labouring but smooth.

 

[dragline1570]

Thanks Drag
Issue is the LH , passenger side of the engine. I cannot be sure all are not firing. In my searching I have see there are pumps on the end of each head. I am thinking more electrical as the first time it did a similar thing it came good after a restart. I would like to check the power feed to the injectors. Not sure how it runs on the treg. Most cars have a constant power feed to the injectors and the ECU grounds the injectors to fire them. Is the treg the same? Do you know where the power feed comes from? Any fuses? Do you have wiring info for what I am talking of? Another reason I am thinking a short circuit as it appears the battery is going flat. I am in a process of measuring the voltage drop. Not sure if it me playing around with the car or there is a problem. I will recheck the voltage in the morning.
Is there any way of seeing the injector duty cycle while its running via the vag com?
I have seen the output test on the vag com. I was little scared in this section so I did not look too hard but can I test the injectors and pulse them.
Thank you very much for your advice.

Well you just sort of shot my plan as your faults are on engine which controls cylinders 1-5 which is the RHS but your issue is LHS ??


With the attachment you should be able to check each injector.


regards
Drag

 

[schootsie]

This is an extract from Ross-Teck Wiki
Contents [hide]
1 16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected
1.1 Possible Causes
1.2 Possible Solutions
1.3 Special Notes
16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected

Possible Causes
Air Intake System leaking
Fuel Supply faulty
Injector(s) faulty
Ignition Cable(s) and/or Spark Plug(s) faulty
Ignition Coil(s) faulty
Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
Camshaft Position Sensor (G40) faulty
Possible Solutions
Check Misfire Recognition
Check Air Intake System
Check Fuel Supply
Check Injector(s) and Injector Sealing
Check Ignition Cable(s) and Spark Plug(s)
Check Ignition Coil(s)
Check Exhaust Gas Recirculation (EGR) Valve (N18)
Check Camshaft Position Sensor (G40)
Special Notes
This DTC indicates that one or multiple cylinders are misfiring, but the ECU fails to identify the cylinder.


From my limited understanding the P0300-000 indicates from the last 3 zeros that it can't pick a specific problem and the other odd thing is that the Fault priority is 3 (not requiring immediate service) ???????

See this link for fault code description
The anatomy of the fault code

Sorry I can't be more help at this stage. John

 

[chrisw]

just out of curiosity, have you checked out the condition of the batteries? I have read a lot of articles on this site about weird problems like this caused by failing batteries that have too low a voltage.