High Pressure Fuel Pump Failure (HPFP)
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High Pressure Fuel Pump Failure (HPFP)
Hi guys, new here.. Our 2011 Q7 TDI has been out of commission for 2 years since the HPFP failed. Mechanic believes the small pump failed causing the big pump to fail or something like that. Doesn’t seem to be many videos on what needs or doesn’t need to be replaced and why. Looking for guidance.. I plan on replacing the pumps and cleaning out the fuel system. Then fire it up and hope for the best. The crazy thing is the HPFP was replaced 30,000 miles earlier under warranty. So, who has some experience with this job?
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Joined: Jan 2021
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From: USA - NM
Doesn't sound like your mechanic is really qualified to guide you in this matter, at least not on this car.
Two years sitting, huh?
Have a gander at this: https://www.fcpeuro.com/blog/fuel-pu...s-misdiagnoses
How do you know it's actually the HPFP? If the lift pump (low pressure pump ) inside the tank fails, then the car simply won't run, as it is not being supplied with fuel from tanks, etc. That could be from a bad relay, bad controller, or a bad in-tank pump. This is not an uncommon scenario on an older Q7, and zero to do with the HPFP...just say'in.
On the other hand, if the HPFP has completely fried and fragged itself (spreads metal glitter) inside your fuel system, then that is a really big problem cause everything expensive has to be replaced on the fuel system, etc., etc., so this is something where you NEED TO KNOW exactly what is wrong. Unless you got some really, really contaminated fuel or air got into the fuel system during filter change, and wasn't purged properly, it would be very doubtful the HPFP would simply die on its' own after only 30k miles of use.
Be very, very specific in your details. There are easy ways to check for glitter (metal flakes) in your fuel system, as well as verify that the lift pump in the tank is operating normally, etc.
Two years sitting, huh?
Have a gander at this: https://www.fcpeuro.com/blog/fuel-pu...s-misdiagnoses
How do you know it's actually the HPFP? If the lift pump (low pressure pump ) inside the tank fails, then the car simply won't run, as it is not being supplied with fuel from tanks, etc. That could be from a bad relay, bad controller, or a bad in-tank pump. This is not an uncommon scenario on an older Q7, and zero to do with the HPFP...just say'in.
On the other hand, if the HPFP has completely fried and fragged itself (spreads metal glitter) inside your fuel system, then that is a really big problem cause everything expensive has to be replaced on the fuel system, etc., etc., so this is something where you NEED TO KNOW exactly what is wrong. Unless you got some really, really contaminated fuel or air got into the fuel system during filter change, and wasn't purged properly, it would be very doubtful the HPFP would simply die on its' own after only 30k miles of use.
Be very, very specific in your details. There are easy ways to check for glitter (metal flakes) in your fuel system, as well as verify that the lift pump in the tank is operating normally, etc.
Last edited by '10Q7TDI_Prestige'; Jan 26, 2025 at 07:26 PM. Reason: ADD HYPERLINK TO FUEL PUMP TROUBLESHOOTING
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Joined: Jan 2021
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From: USA - NM
Hi guys, new here.. Our 2011 Q7 TDI has been out of commission for 2 years since the HPFP failed. Mechanic believes the small pump failed causing the big pump to fail or something like that. Doesn’t seem to be many videos on what needs or doesn’t need to be replaced and why. Looking for guidance.. I plan on replacing the pumps and cleaning out the fuel system. Then fire it up and hope for the best. The crazy thing is the HPFP was replaced 30,000 miles earlier under warranty. So, who has some experience with this job?
My search terms; Q7 TDI no-start video. Please note that a No-Crank scenario is quite diff from a Cranks, but No-Start scenario.
Here's a great one on a gas engine Q7 to watch all the way to the end. Remember, all Q7s use the same fuel pumps.
:
Last edited by '10Q7TDI_Prestige'; Jan 26, 2025 at 04:39 PM. Reason: add detail of No-Crank scenario diff...Devil's in the details.
Thread Starter
AudiWorld Newcomer
Joined: Jan 2025
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Doesn't sound like your mechanic is really qualified to guide you in this matter, at least not on this car.
Two years sitting, huh?
Have a gander at this: https://www.fcpeuro.com/blog/fuel-pu...s-misdiagnoses
How do you know it's actually the HPFP? If the lift pump (low pressure pump ) inside the tank fails, then the car simply won't run, as it is not being supplied with fuel from tanks, etc. That could be from a bad relay, bad controller, or a bad in-tank pump. This is not an uncommon scenario on an older Q7, and zero to do with the HPFP...just say'in.
On the other hand, if the HPFP has completely fried and fragged itself (spreads metal glitter) inside your fuel system, then that is a really big problem cause everything expensive has to be replaced on the fuel system, etc., etc., so this is something where you NEED TO KNOW exactly what is wrong. Unless you got some really, really contaminated fuel or air got into the fuel system during filter change, and wasn't purged properly, it would be very doubtful the HPFP would simply die on its' own after only 30k miles of use.
Be very, very specific in your details. There are easy ways to check for glitter (metal flakes) in your fuel system, as well as verify that the lift pump in the tank is operating normally, etc.
Two years sitting, huh?
Have a gander at this: https://www.fcpeuro.com/blog/fuel-pu...s-misdiagnoses
How do you know it's actually the HPFP? If the lift pump (low pressure pump ) inside the tank fails, then the car simply won't run, as it is not being supplied with fuel from tanks, etc. That could be from a bad relay, bad controller, or a bad in-tank pump. This is not an uncommon scenario on an older Q7, and zero to do with the HPFP...just say'in.
On the other hand, if the HPFP has completely fried and fragged itself (spreads metal glitter) inside your fuel system, then that is a really big problem cause everything expensive has to be replaced on the fuel system, etc., etc., so this is something where you NEED TO KNOW exactly what is wrong. Unless you got some really, really contaminated fuel or air got into the fuel system during filter change, and wasn't purged properly, it would be very doubtful the HPFP would simply die on its' own after only 30k miles of use.
Be very, very specific in your details. There are easy ways to check for glitter (metal flakes) in your fuel system, as well as verify that the lift pump in the tank is operating normally, etc.
I’d like to fix it. I want to turn it into a little Off-Roader. I just can’t believe the cost of injectors for eff’s sake. I could find a whole used engine for that price.
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Joined: Jan 2021
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Likes: 1,456
From: USA - NM
Yeah, it's a very pricey failure if the HPFP grenades and contaminates the entire system. What I can tell you is there's two other owners recently posted on here that tried to take shortcuts after their HPFP's grenaded on their Q7s, and they could never get them running until they finally replaced all the fuel system's parts, and especially the fuel injectors (the very last thing they bought), etc., as well as cleaning fuel tanks, fuel lines 100%.
It's definitely a job where you shop the OEM (HPFP = Bosch CP4 for your model year, etc.) and aftermarket for the required parts rather than buying them from an Audi parts counter. The good news is, on a 2011, the HPFP is mounted to the front of the engine (don't forget the drive belt/tensioner/idlers if they don't come with new HPFP, if those bits weren't replaced via Audi dealer prior...check your Audi invoice)
It's definitely a job where you shop the OEM (HPFP = Bosch CP4 for your model year, etc.) and aftermarket for the required parts rather than buying them from an Audi parts counter. The good news is, on a 2011, the HPFP is mounted to the front of the engine (don't forget the drive belt/tensioner/idlers if they don't come with new HPFP, if those bits weren't replaced via Audi dealer prior...check your Audi invoice)
Thread Starter
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Yeah, it's a very pricey failure if the HPFP grenades and contaminates the entire system. What I can tell you is there's two other owners recently posted on here that tried to take shortcuts after their HPFP's grenaded on their Q7s, and they could never get them running until they finally replaced all the fuel system's parts, and especially the fuel injectors (the very last thing they bought), etc., as well as cleaning fuel tanks, fuel lines 100%.
It's definitely a job where you shop the OEM (HPFP = Bosch CP4 for your model year, etc.) and aftermarket for the required parts rather than buying them from an Audi parts counter. The good news is, on a 2011, the HPFP is mounted to the front of the engine (don't forget the drive belt/tensioner/idlers if they don't come with new HPFP, if those bits weren't replaced via Audi dealer prior...check your Audi invoice)
It's definitely a job where you shop the OEM (HPFP = Bosch CP4 for your model year, etc.) and aftermarket for the required parts rather than buying them from an Audi parts counter. The good news is, on a 2011, the HPFP is mounted to the front of the engine (don't forget the drive belt/tensioner/idlers if they don't come with new HPFP, if those bits weren't replaced via Audi dealer prior...check your Audi invoice)
I know I need to replace the pump and injectors, clean the lines and the tank. What else?
AudiWorld Super User
Joined: Jan 2021
Posts: 4,565
Likes: 1,456
From: USA - NM
in-tank lift pump, if equipped, sensors, rail pressure sensor/ fuel pressure control, etc. Don't reinvent the wheel here; plenty of others have suffered same and documented it...just go search and the threads and videos will pop up on topic.
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