2007 Audi A4 2.0 (BWT) won't start

Reply Subscribe

Thread Tools

Search this Thread

12-24-2016, 11:01 AM

LikMyWagon

AudiWorld Junior Member

Thread Starter

Join Date: Jul 2016

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

2007 Audi A4 2.0 (BWT) won't start

Hey all I posted this in the VCDS forum at VWVortex but I didn't get any answers so I'll try again here. My 2007 2.0 A4 occasionally won't start, it's an intermittent thing and the car mostly starts and drives fine but once in a while it will crank away with no probs but not start up. It only seems to happen after driving for a while the letting it sit for 15-20 minutes, If I let the car sit for 30-60 minutes more the problem goes away and I'm good for a while (a hot electrical/electronic device maybe?). Once started it drives fine so it's not timing or compression then I guess it has to be spark or fuel.

I'm carrying VCDS with me now and have logged measuring blocks 101, 103 and 106 for fuel and they seem ok so I'm guessing it's an ignition problem but I don't know for sure or where else to trouble shoot. Can anyone with more VCDS experience, which is pretty much anyone, tell me what measuring blocks I should look at the next time it happens? FWIW the HPFP, G410 and fuel filter have been replaced with no fix. Also I have a couple of Excel logs if anyone thinks they can figure it out from them let me know.

Non VCDS suggestions would also be appreciated, I've had a few people suggest crank or cam sensor which sounds plausible but if either of those items are the source of the engine RPM data in VCDS I have captured realistic RPM numbers, and fuel lift pump and fuel rail pressures logging failed starts.

Thanks

Attached Files

LOG-01-022-055-106 failed start 2 dot xlsx.doc (4.1 KB, 154 views)

LOG-01-022-055-106 failed start.csv (11.4 KB, 147 views)

Excel LOG-01-022-055-106 failed start 3.csv.doc (4.2 KB, 172 views)

LOG-01-022-055-106 start and move car .csv (10.8 KB, 141 views)

LOG-01-02D-038-618-871-103F-1063.CSV (277.4 KB, 143 views)

LOG-01-03C-061-201-556-103F-1063.CSV (27.2 KB, 145 views)

Reply Like

12-24-2016, 12:19 PM

clancy

AudiWorld Senior Member

Join Date: Jan 2004

Location: Ocean Isle Beach NC

Posts: 1,413

Likes: 4

Received 25 Likes on 23 Posts

Don't know if your car has a crank position sensor but the symptoms are the same. My 2001 C5 had this issue.

Reply Like

12-31-2016, 03:19 PM

LikMyWagon

AudiWorld Junior Member

Thread Starter

Join Date: Jul 2016

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

Quote:

Originally Posted by clancy

Don't know if your car has a crank position sensor but the symptoms are the same. My 2001 C5 had this issue.

Thanks

Reply Like

12-31-2016, 03:24 PM

LikMyWagon

AudiWorld Junior Member

Thread Starter

Join Date: Jul 2016

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

Either the web site or my computer is being a dick, meant to say Thanks a couple of people have mentioned that it might be either the crank or cam position sensor. I'll dig into that a little further.

Reply Like

12-31-2016, 03:30 PM

LikMyWagon

AudiWorld Junior Member

Thread Starter

Join Date: Jul 2016

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

Dug into the logs I generated and I've discovered that when the engine stumbles while idling (that's new as of today) and sometimes won't start VCDS measuring block 106 shows the "Fuel Rail Pressure" dropping to between 5-7 bar. Normal (as far as I can tell) idle rail pressure is around 50 bar and higher engine loads produce pressures of around 100 bar. Again this only happens occasionally with a warmed up engine and for the most part the car runs great. Also whenever it does occur leaving the car 30-40 minutes to cool down solves the problem, as least until the next time.

Thanks and Happy New Year to all.

Reply Like

12-31-2016, 03:41 PM

LikMyWagon

AudiWorld Junior Member

Thread Starter

Join Date: Jul 2016

Posts: 8

Likes: 0

Received 0 Likes on 0 Posts

Also did a VCDS scan today and got these 3 codes for the Address 01 Engine section, maybe it is a fuel problem but it seems to come and go and when it does occur letting it cool down cures it for a while.

Address 01: Engine Labels: 06F-907-115-AXX.lbl

3 Faults Found:
012555 - Low Pressure Fuel regulation
P310B - 004 - Fuel Pressure Outside Specification - Intermittent
Freeze Frame:
Fault Status: 00100100
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 195043 km
Time Indication: 0

Freeze Frame:
RPM: 748 /min
Load: 15.7 %
Speed: 0.0 km/h
Temperature: 101.0°C
Temperature: 43.0°C
Absolute Pres.: 990.0 mbar
Voltage: 13.335 V

000135 - Fuel Rail/System Pressure
P0087 - 002 - Too Low - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 195144 km
Time Indication: 0

Freeze Frame:
RPM: 303 /min
Load: 66.6 %
Speed: 0.0 km/h
Temperature: 98.0°C
Temperature: 60.0°C
Absolute Pres.: 990.0 mbar
Voltage: 12.192 V

005634 - Power Supply Terminal 30
P1602 - 002 - Voltage too Low - Intermittent
Freeze Frame:
Fault Status: 00100010
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 0 km
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Load: 0.0 %
Speed: 0.0 km/h
Temperature: -40.0°C
Temperature: -40.0°C
Absolute Pres.: 0.0 mbar
Voltage: 0.000 V

Readiness: 0000 0000

Reply Like