2011 Audi A3 TDI hatch - Bargain or dumpster fire?

Yesterday I took a deposit on the Fiat 500 Turbo I put together earlier this year, and promptly purchased a new project. I've been wanting another automatic commuter for the days I don't want to drive my Jeep XJ and this one popped up. The FB MP ad was listed as $3295 if I remember correctly and listed that it needed injector work. I kept an eye on the ad for a couple weeks thinking it wasn't quite what I was looking for but my previous A3 was a fun car. Surprisingly easy to work on, but had some standard VAG quirks. I had dealt with a crank no start before which ended up being a $1k turbo replacement. If this car had that same problem it would still put me in a good deal territory. Of course I assumed that's what the problem was with this car....

So I checked it out and decided to offer $2500. Didn't think they would take it as this is the dealer side of a local U Pull It but they did and also offered free delivery to my house. Same day delivery at that!

It's a 2011 Audi A3 TDI FWD with the DSG. The interior is pretty skanky but should clean up decent. Paint isn't too bad overall with a couple touch up spots needed at the front bumper and a ding in the driver rocker under the passenger door. 136k miles on the clock with a religious oil change service history.

We can focus on interior pics later. Time to dive into the wonderful world of the CBEA fuel system!

So as mentioned before, my previous A3 had a crank no start symptom with zero fault codes. It seemed like that's where this was headed so I spent a few minutes pulling off the intake side to look at the impeller.

Here's what it looked like on my old one:

Here's what it looked like on this new car:

So the good news is the turbo is in okay shape. There's a little shaft play but for now this is a functional part. The bad news is the fuel system appears to be the problem. Reading up on any TDI high pressure fuel pump replacement will scare the E36 M3 out of you. Thousands of dollars to essentially replace EVERY SINGLE FUEL RELATED ITEM.

My OBD Eleven reader shows only 8 bar while cranking for the HPFP. That's frickin scary. Really fricking scary.

First thing to check is the fuel filter. Super easy to access and should have lots of metal flakes in it if the HPFP is going bad. Didn't snap pics because covered in diesel fuel but newly clean filter with no metal particles in it. That's a good sign.

Then I pulled the Fuel Metering Valve to find zero metal swarf. This is another great sign!

Then I pulled the in tank fuel transfer pump under the rear seat. There was some metal debris in the basket, but a very small amount. Nothing large or alarming. Still not giving me a warm fuzzy feeling. After cleaning it up really well I tested to make sure it was still functional. The pump still hums away beautifully. So it went back in the tank for now. Later I will drain the complete tank to clean any possible debris leftover. Currently it is filled to the brim.

I also tested to make sure fuel was flowing out of the supplementary fuel pump that feeds the filter. Didn't get a great look at the flow rate but it filled up my container with ease.

I'm still feeling like this could be a high pressure fuel pump since there have been others tinkering on this car before me. The mechanic that worked on it gave up or the guy who owned it couldn't afford to figure it out. So maybe they were a shop that fires the parts cannon at it or just didn't want to mess with it? I have his address and am planning to reach out. Maybe he is willing to expand how things transpired.

Anyway I saw a DIY on how to open up the pump for inspection without removing the timing belt. Again no pics with any of this stuff because everything just is caked in fuel. After popping it open I was greeted with a beautiful pump internally. No scarring, marring, metal bits, worn surfaces, it was glorious. I was certain to keep everything clean when reassembling as well as getting the piston in the correct orientation. On to the next.

Now I have a few things to consider. The injectors are clogged up or one is bleeding off due to the way they are designed which will not allow the rail to achieve pressure. Another option is the fuel pressure regulating valve could have failed or is clogged.

I think I want to pull the injectors and try cleaning them? Rebuilt Bosche units are around $300 PER INJECTOR! So it could be around $1200 for the injectors which isn't too far off from where I had hoped to be. I figure it's worth a shot trying to clean the ones I have or figure out how to test if it's just one taking a E36 M3. I really just want to know for certain before spending money.

Man all I can say is pray it's not the HPFP failure. A couple years ago, I bought a 2012 Golf TDI (same chassis and engine as your A3) that ran and drove fantastic and I think I spent about 10K on it. Literally the day I brought it home, flashing check engine light and the car had virtually no power but it's still ran until I got it home. After getting it home, wouldn't restart. Opened the fuel filter and it was definitely a glitter bomb. Towed it to a local VW shop that I trust, they confirmed hpfp failure and it needed replacement of, or cleaning of literally everything that fuel touches. Car was basically mechanically totaled at that point but I ended up just paying for it, doing a CP3 fuel pump upgrade while I was at it, and then about 2 weeks later check engine light came on for the DPF which turned out to have a crack in it. Traded it in and just swallowed the massive, massive loss. The sad part is the cars drive fantastic when everything's working properly. I would consider buying another one if and only if I was ready to immediately do a CP3 fuel pump upgrade and full deletes as then they're actually Fairly reliable. 

In reply to LukeGT :

So far I think I've dodged the bullet. The car was sold by the exact same dealer I bought mine from years ago, and he was getting all of his supply of cars from the dieselgate buyback. The one I purchased had a full brand new fuel system, and I have a suspicion based on how good the internal of the HPFP looked that this has all be replaced before. I'm hoping to get in contact with the previous owner of this car in hopes to get more of that information. Fingers crossed he actually answers back.

I have found a few sets of used injectors on ebay for roughly $300 shipped. Not ready to pull the trigger on them yet but I think that might be the direction I go to save money. Realistically I just want to be able to test the ones I have to see if any of them are bleeding back into the system but can't seem to track down how to do that. There has to be a way to narrow down which one or ones that could be failing.

Just checked resistance across all injectors and every single one of them measured 182ohms. Pretty sure that's right in spec but will dig a bit further. This makes me feel more confident in the idea of cleaning them but I don't have an ultrasonic and that's required to do it properly. More head scratching needed.

Following as I really enjoy your builds. 

I know diesels run insane fuel pressures, but is removing them from the head and cranking the car while they are attached to the rail an option to see how they spray or if they are leaking?

In reply to Slippery :

Funny you mention that, I saw a post where they were able to see a difference on one vs the other three by doing that. No pics but there's got to be a way to set them up to spray in a large tote while cranking. Hopefully not too messy but certainly a cheap way to see if there's an obvious damaged one.

Following since I've got two TDI's in my garage, both the V6...

In reply to captainawesome :

This is what I did with my M3. Gas engine, so lower pressure, but it help me id the problem injector. Put a plastic cup under each injector.

In reply to Slippery :

I went back and re-read what the guy wrote and he mentioned 12oz bottles for each injector but an 8oz might fit better in the space allowed. Maybe I can mess with it tomorrow evening. Apparently it can be a bit of bear pulling the injector if you can't warm the car up first. More reading to do on that as well.

In reply to captainawesome :

Yeah, diesel injectors can be a royal pita to remove. I have to change a leaky valve cover gasket on my wife's diesel BMW and have been putting it off just because I dread pulling the injectors. 

Found a better picture:

Just a word of caution, common rail fuel pressures are crazy - upwards of 20k psi. I'd be very hesitant to fire them outside of the engine unless I had something pretty robust to contain the spray. Hydraulic injection injuries are no joke

In reply to Turbine :

From what I understand the pressure is enormous but the spray is a fine mist. I definitely plan to proceed with caution. Oh and this will be under cranking pressure, which currently is equating to 8 bar max. Hoping the rail regulator to be the culprit but need to see how to test one.

So I can test the fuel pressure regulator valve on the return line while cranking. If it sends ANY fuel through the return while cranking the valve is bad. If I could actually get the car running there's a return value of 100ml +/- 10%. That may be my evening test while I figure out a slide hammer/injector puller.

Wishing you all the best here and I'll be following along but having owned a VAG TDI, I'd definitely vote put it in the dumpster and light it and all of the diesel on fire with gasoline.

Any chance the system just has to be bled? Maybe in replacing all of the bits they got air in the system and it's not allowing it to actually get fuel to the rail?

I thought you really liked the Fiat... what happened with that one?!

In reply to AxeHealey :

So far everything I am opening up is filled with fuel just not getting pressure. I need to either update my OBD Eleven app to have the prime feature or get the VCDS app/dongle. I think I would at least get some sputter if it was just a prime issue though. I'm not even getting a cough.

In reply to golfduke :

I really did enjoy it. The problem was it just sits in the garage. I've grown tired of driving manual trans cars anymore, and every time I drove it to work would be the one day of crappy traffic. Never failed.

Spent a few minutes bouncing around checking various things.

The Fuel Pressure Regulator Valve N276 didn't spit any fuel out while cranking, so in theory it is working correctly. I measured 4 ohms of resistance as well, which I'm still trying to find specs on.

The Fuel Metering Valve N290 is reading 3 ohms. Again, still unclear what the specs should be. Need to track down a Bentley manual or similar?

The Fuel Pressure Sensor G247 has three pins and depending on where I measure the values vary. One specifically climbs to around 40 and then slowly works down to around 12 before I got tired of waiting. More info needed on this as well.

I cracked open each of the injector feed lines and cranked the car to manually bleed the system. Still not even a sputter. 8 bar max showing on cranking once they were tightened back up. Fuel was present, and when just one was slightly opened it sprayed all over my phone. Yay. This one also suspiciously wiggled when I started loosening the fuel line, so maybe it's leaking out the copper seal?

I ordered an injector puller tool which should be here this afternoon. Tonight I hope to set all 4 up to check spray pattern as well as general condition of the nozzles.

I also updated my OBD Eleven to Pro so I could prime the fuel pumps as well as see more detail scan data. Even with the priming of both lift and accessory pump I'm left with a PC00C6 Fuel Pressure Too Low - Engine Cranking - Lower limit not reached.

There's also this injector flow rate tool that may be able to show if one of the injectors is bleeding off pressure while cranking. Hmmm. Might order one and wait another day to test.

be aware that there are crush washers under the injectors to seal them to the head and there are also body orings that are pretty delicate. I know this is GRM but you are supposed to replace both when you pull injectors. 

VCDS is super handy for working on these cars. it is expensive relative to what it used to be but i think its worth it

In reply to metty :

Definitely going to replace them if the injectors are still in good shape. Probably going to hold off on pulling them this evening and do a bleed test tomorrow. I ordered the kit above which should hopefully help answer my question quicker.

I do plan to get VCDS at some point but I already had the dongle for the OBD Eleven which can do just about everything VCDS can do from my phone. There are some things that are different and maybe not as easy to navigate but has a lot of useful features. Now that I upgraded to the PRO version for $54 I have access to most of VCDS capability other than graphing. I didn't want to pay $200 and then wait for the VCDS dongle to arrive. I think having both will be beneficial though.

Is 136k just after the recommend timing belt change interval, or am I thinking of the wrong year?

In reply to MadScientistMatt :

Correct. It's due at 130k and will be replaced as soon as I get it running. I've pulled the cover back enough to see a decent belt still intact, so for now it's doing it's job or at least appears to be. The water pump will be replaced as well as a full DSG fluid service as I think that wasn't done when required either. At least the changed the oil and filter consistently though.

Sitting bored up and work. Searched for the dealer I bought my first A3 from and our family picture popped up through the Facebook feed. Thought it might be possible to find this blue one and sure enough there it was since we both went through the same dealer. We purchased the Lava Gray one in August of 2020 and the guy bought the Deep Sea Blue Pearl in October of 2019.  I redacted his face out of respect. I also may have stumbled on his phone number, called and left a message. Hopefully he will get back with me.