3.6 won't start
Thread Starter
AudiWorld Junior Member
Joined: Oct 2013
Posts: 8
Likes: 0
From: Winnipeg, Manitoba, Canada
3.6 won't start
Hi
I bought q7 from the auction not long ago. It was advertised as not running and not driving. Imagine my surprise when the car started and drove
A few weeks passed and the car went to the shop for body integrity assessment. After the assessment engine doesn't want to start anymore. It turns over, sounds like it's about to start but dies after a second or so. It is noticeable sound of air/vacuum releasing from the right side (passenger) of the engine and the smell of gas. VCDS doesn't show anything, apart from no communication with the battery module which I know about as needing to be replaced! It is way too cold in Winnipeg at this moment to try anything outside.
Does 3.6l have a high-pressure fuel pump? I'm just wondering, maybe the electric fuel pump doesn't work? Didn't check the fuses yet, as I mentioned is way too cold!!!
Maybe one of you had heard about a similar issue?
It is 2007 4L.
Thank you
I bought q7 from the auction not long ago. It was advertised as not running and not driving. Imagine my surprise when the car started and drove
A few weeks passed and the car went to the shop for body integrity assessment. After the assessment engine doesn't want to start anymore. It turns over, sounds like it's about to start but dies after a second or so. It is noticeable sound of air/vacuum releasing from the right side (passenger) of the engine and the smell of gas. VCDS doesn't show anything, apart from no communication with the battery module which I know about as needing to be replaced! It is way too cold in Winnipeg at this moment to try anything outside.
Does 3.6l have a high-pressure fuel pump? I'm just wondering, maybe the electric fuel pump doesn't work? Didn't check the fuses yet, as I mentioned is way too cold!!!
Maybe one of you had heard about a similar issue?
It is 2007 4L.
Thank you
AudiWorld Member
Joined: Jan 2021
Posts: 406
Likes: 78
Maybe you have a fuel leak from the high pressure side? All the injectors and rails are on the driver side. Maybe one of the vacuum pipes on the passenger side cracked? But you should still not smell gas that way. Is there fuel raining down from the engine?
Yes, the 3.6L has a Hitachi high pressure fuel pump on the driver side of the engine by the firewall where the fuel hoses are. If the low pressure pump still works, and depending how the high pressure pump failed, the engine should still run but very rough. If there are no fault codes from VCDS, then check the fuel rail pressure. Group 140 field 3. It should give the P229x codes and maybe a low fuel rail pressure code.
https://www.audizine.com/forum/showt...shooting-P2294
When my HPFP went bad, the fuel pressure stuck at 6 bars (90 PSI), so I know the low pressure pump in the tank is working.
Yes, the 3.6L has a Hitachi high pressure fuel pump on the driver side of the engine by the firewall where the fuel hoses are. If the low pressure pump still works, and depending how the high pressure pump failed, the engine should still run but very rough. If there are no fault codes from VCDS, then check the fuel rail pressure. Group 140 field 3. It should give the P229x codes and maybe a low fuel rail pressure code.
https://www.audizine.com/forum/showt...shooting-P2294
When my HPFP went bad, the fuel pressure stuck at 6 bars (90 PSI), so I know the low pressure pump in the tank is working.
AudiWorld Newcomer
Joined: Feb 2022
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I have an 08 q7 3.6 Premium that cutoff while driving on the freeway and would not restart. Had it towed to a local shop where they found that the HPFP had failed. New pump installed and has been operational ever since.
Thread Starter
AudiWorld Junior Member
Joined: Oct 2013
Posts: 8
Likes: 0
From: Winnipeg, Manitoba, Canada
Looks like the issue was a faulty/badly corroded battery control module located under the driver's seat! I replace it and fixed a few exposed wires. The car started after that! I hope it will kee[ running. Thank you
Last edited by jocker01; Feb 14, 2022 at 07:21 AM.
AudiWorld Super User
Joined: Jan 2021
Posts: 4,568
Likes: 1,456
From: USA - NM
FWIW, be advised the door handle sensors create parasitic battery drains (constant, low-amp drain) eventually, as they fail. It is easily resolved w/o having to open the door panel (search for "Got Parasitic Drains" thread), but if left unresolved it will kill your battery and create lots of havoc within this highly voltage-sensitive car. The functionality of the doors auto-unlocking is greatly enhanced once the parasitic drain issue is resolved.
Also, you should be aware that Audi doesn't schedule any driveline service intervals to replace the fluids (front/rear differentials, transfer case, transmission), so they've planned for those expensive bits to fail in the long-term by excluding them from the normal service intervals required to maintain fluid integrity, shear forces/heat protection, and particle suspension, etc.
Also, you should be aware that Audi doesn't schedule any driveline service intervals to replace the fluids (front/rear differentials, transfer case, transmission), so they've planned for those expensive bits to fail in the long-term by excluding them from the normal service intervals required to maintain fluid integrity, shear forces/heat protection, and particle suspension, etc.
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