Intermittent hard or no start on 4.0T S6 S7 RS7- possibly solved

**aFOURstance** · 12-29-2018 08:49 AM

You guys still having issues?

**Hofahome** · 01-03-2019 04:33 PM

A bit of an update.
My car was driving great for a few days after the injectors were replaced but then threw cel for closed intake flaps. Do not exceed 4k rpm. Great.

My mechanic knew the flaps were installed correctly so the thought was one of the vacuum lines came off. I took the car in and he tested the lines, all was good. He then tested the vacuum solenoid and no dice. My mechanic is a good friend and he said they didn’t even touch the solenoid during recent service and I believe him. So basically it was just bizarre timing after my recent injector replacement. Turns out there is a tsb for this on our motors fyi.

I miss driving my car...

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**brad281** · 01-03-2019 04:38 PM

Originally Posted by Hofahome

A bit of an update.
My car was driving great for a few days after the injectors were replaced but then threw cel for closed intake flaps. Do not exceed 4k rpm. Great.

My mechanic knew the flaps were installed correctly so the thought was one of the vacuum lines came off. I took the car in and he tested the lines, all was good. He then tested the vacuum solenoid and no dice. My mechanic is a good friend and he said they didn’t even touch the solenoid during recent service and I believe him. So basically it was just bizarre timing after my recent injector replacement. Turns out there is a tsb for this on our motors fyi.

I miss driving my car...

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Damn! Sorry to hear. Easy fix?

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**wwhan** · 01-03-2019 06:14 PM

Originally Posted by aFOURstance

No CEL, no soft codes via VCDS, no warnings

There is also this 4.0T TSB 204672/4 Oct2017, hard to start, no codes.

**Hofahome** · 01-03-2019 06:55 PM

Originally Posted by wwhan

There is also this 4.0T TSB 204672/4 Oct2017, hard to start, no codes.

Fuck that would have been helpful a month ago to me. But thx for posting here for others.

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**Hofahome** · 01-03-2019 06:59 PM

Originally Posted by brad281

Damn! Sorry to hear. Easy fix?

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Thx man. Hopefully this thread can help someother poor sap. I honestly dont know yet about the fix.

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**wwhan** · 01-03-2019 09:34 PM

....that would have been helpful a month ago to me. But thx for posting here for others.
......

Well, I did in post #10, the TSB number (204672/4) a month ago (11-09-2018 ): https://www.audizine.com/forum/showt...1#post13383505

"There is a TSB:

TSB 01 17 37 204672/4, October 4, 2017

01 engine sporadically difficult to start - 4.0tfsi

Update ECM software "

**russjameson** · 01-04-2019 03:10 PM

Originally Posted by wwhan

Well, I did in post #10, the TSB number (204672/4) a month ago (11-09-2018 ): https://www.audizine.com/forum/showt...1#post13383505

"There is a TSB:

TSB 01 17 37 204672/4, October 4, 2017

01 engine sporadically difficult to start - 4.0tfsi

Update ECM software "

has anyone gotten this done yet and fixed the issue. This is what I was told will cost $270 and will probably flash me back to stock. I told my APR dealer to be ready for me to come in for a reflash back to stage 3 if and when I get this TSB done.

**aFOURstance** · 01-04-2019 04:12 PM

Originally Posted by russjameson

has anyone gotten this done yet and fixed the issue. This is what I was told will cost $270 and will probably flash me back to stock. I told my APR dealer to be ready for me to come in for a reflash back to stage 3 if and when I get this TSB done.

Worth a shot

**brad281** · 01-23-2019 06:45 AM

Originally Posted by Hofahome

Fuck that would have been helpful a month ago to me. But thx for posting here for others.

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Any update? Did the injectors solve the starting issue?

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**Hofahome** · 01-24-2019 08:48 AM

Originally Posted by brad281

Any update? Did the injectors solve the starting issue?

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Seems good so far but I have only had my car back for a few days. There was a side issue of a bad vacuum solenoid and the warranty company dragged their feet on approving it.

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**russjameson** · 02-20-2019 11:30 AM

has anyone learned any more on the no starts? It is getting annoying, and all the dealer wants to do is poke at it, but on my dime. and homey aint playin that with no warranty.

**brad281** · 02-20-2019 11:34 AM

Originally Posted by russjameson

has anyone learned any more on the no starts? It is getting annoying, and all the dealer wants to do is poke at it, but on my dime. and homey aint playin that with no warranty.

I just had mine in for upgraded turbos, PCV and some other maintenance. They replaced my plugs and didnt see any fouling on the plugs, so he didn't think I had an injector issue. Leaning towards HPFP, which is a significantly cheaper repair. It hasn't done the hard start since I've had it back, so I'm not sure if it was turbo related, but I doubt it.

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**Avned** · 02-20-2019 07:01 PM

Mine was solved when the injectors were replaced. My tuner first tried the fuel pumps but that didn't solve the issue. It's been several months now and no more starting issues.

**russjameson** · 03-07-2019 06:36 AM

Originally Posted by Avned

Mine was solved when the injectors were replaced. My tuner first tried the fuel pumps but that didn't solve the issue. It's been several months now and no more starting issues.

Which fuel pumps, the HPFPs in the engine bay?

**Qweklain** · 03-29-2019 05:28 PM

I am having this issue right now. Started about two weeks ago when we started getting temperatures consistently above 40 degrees Fahrenheit. My car runs fine, starts fine cold or shortly after turning it off (within ~20 minutes or less) if warmed up, but if it sits for around 45 minutes or so, or when it has cooled down a bit, it will die as soon as it fires. If I do not hit the gas a bit when it fires, I have to wait at least a minute or two before I can try again because it just cranks after that first pop.

**wwhan** · 03-29-2019 08:46 PM

Another interesting TSB ; https://static.nhtsa.gov/odi/tsbs/20...19940-9999.pdf

“01 15 14 2014753/9 March 9, 2015. Supersedes Technical Service Bulletin Group 01 number 13-09 dated June 21, 2013 for reasons listed below.”

“Supersedes Technical Service Bulletin Group 01 number 13-09 dated June 21, 2013. The use of contaminated gasoline or gasoline with a low content of deposit control additives may result in excessive accumulation of deposits on intake valves, intake manifold, fuel injectors, and combustion chambers, engine running rough after cold start, excessive engine cranking time, hesitations while driving, rough engine idle, Reduced engine performance, and/or Poor fuel economy. Conditions may be severe enough to illuminate the MIL in conjunction with storage of DTCs for misfire, lean fuel system, or air/fuel ratio imbalance in the engine control module. Condition may be caused by use of contaminated gasoline. Condition may be caused by use of gasoline with a low content of deposit control additives.”

“Repair:
Gasoline additive G 001770A2 can be used for removal of existing carbon deposits from:
• Injectors (MPI and FSI engines)
Combustion chambers (MPI and FSI engines)
• Intake valves (MPI engines only)
Mix the additive with gasoline directly in the full fuel tank following the mix ratio. For example, 60 ml per 20 liters gasoline or 120 ml per 10 gallons of gasoline.
Tip: For removal of carbon deposits from intake valves of FSI engines, refer to TSB 2019948.“

**Qweklain** · 04-12-2019 06:51 PM

Originally Posted by Qweklain

I am having this issue right now. Started about two weeks ago when we started getting temperatures consistently above 40 degrees Fahrenheit. My car runs fine, starts fine cold or shortly after turning it off (within ~20 minutes or less) if warmed up, but if it sits for around 45 minutes or so, or when it has cooled down a bit, it will die as soon as it fires. If I do not hit the gas a bit when it fires, I have to wait at least a minute or two before I can try again because it just cranks after that first pop.

Just thought I would update here that I found out I am running the latest version of the ECM which already contains the SVM for TSB 2046724/4 that has a description describing this issue. Obviously I am having the issue with this "fix" already applied, so it is something else.

I am going to be taking off my HPFPs and cleaning them. I am 95% sure the pumps themselves are perfectly fine, just like everyone else here having the issue. I personally think the culprit is the stupid fuel regulator sensor that plugs into our HPFPs that, of course, you cannot buy separately and have to buy a whole damn new pump. If the cleaning does not work, I will probably try to find out what the exact sensor is (Nxx, something like that), find what other vehicles use these pumps, and find some cheap ones to get different sensors.

**Hofahome** · 04-12-2019 09:45 PM

Originally Posted by Qweklain

Just thought I would update here that I found out I am running the latest version of the ECM which already contains the SVM for TSB 2046724/4 that has a description describing this issue. Obviously I am having the issue with this "fix" already applied, so it is something else.

I am going to be taking off my HPFPs and cleaning them. I am 95% sure the pumps themselves are perfectly fine, just like everyone else here having the issue. I personally think the culprit is the stupid fuel regulator sensor that plugs into our HPFPs that, of course, you cannot buy separately and have to buy a whole damn new pump. If the cleaning does not work, I will probably try to find out what the exact sensor is (Nxx, something like that), find what other vehicles use these pumps, and find some cheap ones to get different sensors.

Just an FYI, you can buy the low pressure fuel sensor/regulator (G410) that sits on the driver side hpfp. It is the fuel metering valves cannot be bought separate from the pump. But that is probably not the issue. According to my SA at Audi these pumps tend to fail internally, leaking gas into the valvetrain. Not sure if this is somehow related to injector failure but I bet in some way they are connected.

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**Qweklain** · 04-18-2019 01:05 PM

Originally Posted by Hofahome

Just an FYI, you can buy the low pressure fuel sensor/regulator (G410) that sits on the driver side hpfp. It is the fuel metering valves cannot be bought separate from the pump. But that is probably not the issue. According to my SA at Audi these pumps tend to fail internally, leaking gas into the valvetrain. Not sure if this is somehow related to injector failure but I bet in some way they are connected.

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You were right, it was not the metering valves nor the pressure sensor. The goddamn spring was broke at two points on the passenger HPFP!! So now I have to fork out $500 for a new pump for a fucking spring or try to find (what seems non-existent) a probably ~$200 pump for a used one. I am going to try to contact Audi USA to see if there is anything they will be willing to do, but I highly doubt it since I diagnosed it myself instead of paying probably $1000+ for a stealership to poke and prod at it since it was not throwing codes for what is obviously a manufacturer defect. Make me wonder why these pumps have four revisions for newer years of cars using this 4.0t...

The actual pumps themselves are fine as I took them apart and cleaned them. I cleaned this particular pump after taking this photo, so do not think I left it looking this gross.

**wwhan** · 04-18-2019 05:54 PM

There is another TSB...

TSB 01 Engine sporadically difficult to start - 4.0TFSI
01 19 00 2046724/7 January 11, 2019

"Customer statement:
The engine sporadically does not start after reaching operating temperature and being parked for longer
stationary periods (engine not completely cooled down). However, the starter motor will turn over normally.
The engine sporadically does not start or only after long cranking period then runs rough for a few seconds
(starter motor turns normal).
Workshop findings:
Usually there are no DTCs in the engine control module (ECM), J623 (address word 0001).
Or
Sometimes a DTC about fuel metering system "System too rich" will appear in the engine control module
(ECM), J623 (address word 0001).
Technical Background
Deviation in fuel-air mixture at engine start."

"Service
Perform the following checks:
1. Read the DTC memory of the ECM.
2. Read/assess the measured value with the ODIS measured value identifier IDE09529 "Fuel mass flow
fumigation from engine oil". Warm up the engine at idle speed and observe the above measured value
together with the engine oil temperature. The evaporation process of fuel in the engine oil starts at about
122°F engine oil temperature.
a. If the value of the fuel mass flow is at least intermittently above 75 mg/s, this clearly points to a high fuel
share in the engine oil (over 0.5 l). In this case, the condition is caused by an extreme short distance
operation profile of the customer. We recommend to change the engine oil with filter and to explain the
background to the customer. Update the ECM with SVM code 01A225.
b. If the limit of 75 mg/s is not exceeded and the condition cannot be reproduced, the driving profile of the
customer before the workshop visit may have completely consumed the fuel in the engine oil. In this case,
we also recommend to enquire about the driving profile of the customer for a possible explanation."

"If high pressure fuel pump/pumps are replaced use Service Number 2463, Damage Code 0050."

**Qweklain** · 05-06-2019 08:40 AM

I found a spring and got it in a couple days ago. The good news is the spring is the same as almost every HPFP Audi has used on any of their v8s in the last 10 or more years (there are exceptions I found). Basically, if the spring uses a retainer like the one in the picture in my previous post, it is the same spring. The other spring they use is the one that they use in, for example, their 2.0 TFSI. It does not have a split retainer and the piston itself does not sit on the tappet the way our HPFP springs do.

The bad news is now my car runs better than I can remember when it is cold, but when it is warm enough for the RPM limiter to remove itself (aka go into close loop), the car dies, pretty much will not start and if it does, the idle surges by about 600 RPM, and it misfires constantly. I am pretty sure it is my tune to be honest as I believe the changes that were made to it after the base stage one was applied has now put the amount the ECU can adjust out of its capability, but I am just theorizing with that one at this point. The car does run perfect when it is cold (in open loop) though.

**Qweklain** · 05-26-2019 07:23 AM

Figured I would post up here in case more people start having this issue (or still are without resolve). I have gone back to stock and my car runs fine ~85% of the time, however, the tune was not the issue, it was just making the issue worse. The car was running so rich due to the alteration from the tune that the car was maxed out on how much fuel it could pull. Now it runs, but it still has hard starts when warm sometimes and runs rich too much, but usually the rich aspect is only at idle or when off-throttle.

I did find the cause of what causes the hard-starts, at least in my case (see attachments). Basically, whatever the root cause is is causing the high-pressure to build-up so high, with the car off, that when you crank the motor you flood it out. Take a look at the three log snips I attached and you will see the high-pressure is way too high and these are with the car off! I have plenty of logs showing that these high pressures are not normal and the hard-starts only happen when this pressure build-up occurs. The log with the blue horizontal highlight is right when the motor died.

If you want to log what I am logging, use the variables below.

IDE00148
IDE00186
IDE00188
IDE00201
IDE00202
IDE00559
IDE00565
IDE00597
IDE00598
IDE00604
IDE00605
IDE01869

**mtaylor505** · 12-16-2019 04:57 AM

Hi all, thanks for writing up all of your collective experiences. I recently purchased a 2013 Audi S6 and a day after I drove it home, it did the non-start many of you have described, (no wonder he sold the car). 30+ minutes after driving, cranking and turning over and then dying as the revs fell. Starts if I apply some throttle while cranking.

Car is 100% stock with 78k miles. The turbos have been replaced by Audi at 55K along with the oil separator. I brought it to Audi last week as it needed a new key programmed so I figured I would have them take a look at it. After a few hours as well as consulting some outside sources at Audi, the only thing they could find was a fault in the transmission module. They reset it but of course that wasn't the culprit.

My hope in reactivating this thread is to get a sense for what I should try doing first. I am not very mechanical and its out of warranty so I will be paying my independent Audi mechanic for diagnosis time and I am hoping to point him in the right direction. Have any of you definitively solved the issue with some of the above various fixes?

Thanks in advance.

**15 Phantom S6** · 12-16-2019 06:59 AM

Originally Posted by mtaylor505

Hi all, thanks for writing up all of your collective experiences. I recently purchased a 2013 Audi S6 and a day after I drove it home, it did the non-start many of you have described, (no wonder he sold the car). 30+ minutes after driving, cranking and turning over and then dying as the revs fell. Starts if I apply some throttle while cranking.

Car is 100% stock with 78k miles. The turbos have been replaced by Audi at 55K along with the oil separator. I brought it to Audi last week as it needed a new key programmed so I figured I would have them take a look at it. After a few hours as well as consulting some outside sources at Audi, the only thing they could find was a fault in the transmission module. They reset it but of course that wasn't the culprit.

My hope in reactivating this thread is to get a sense for what I should try doing first. I am not very mechanical and its out of warranty so I will be paying my independent Audi mechanic for diagnosis time and I am hoping to point him in the right direction. Have any of you definitively solved the issue with some of the above various fixes?

Thanks in advance.

You mention the oil separator being replaced but no mention if the turbo oil screen was replaced when the turbos were replaced.. IF the oil screen wasn't replaced at the time the turbo's were installed, you could have turbo failure.. What specifically did the dealer check for to come up with basically nothing?

How long ago were the turbos replaced? Even though your warranty might be over, there might be some warranty left on the new turbos if they were replaced somewhat recently..

**mtaylor505** · 12-16-2019 07:49 AM

Originally Posted by 15 Phantom S6

You mention the oil separator being replaced but no mention if the turbo oil screen was replaced when the turbos were replaced.. IF the oil screen wasn't replaced at the time the turbo's were installed, you could have turbo failure.. What specifically did the dealer check for to come up with basically nothing?

How long ago were the turbos replaced? Even though your warranty might be over, there might be some warranty left on the new turbos if they were replaced somewhat recently..

I will triple check the receipts when I get home, but I believe the oil screen was done as well. The car runs flawlessly aside from the intermittent non-start, so I would be surprised its turbo failure, but I'll certainly check that the oil screen was replaced.

**wwhan** · 12-16-2019 11:52 AM

Originally Posted by mtaylor505

I will triple check the receipts when I get home, but I believe the oil screen was done as well. The car runs flawlessly aside from the intermittent non-start, so I would be surprised its turbo failure, but I'll certainly check that the oil screen was replaced.

Pop the oil cap off and check if you smell gasoline, if so then maybe change the oil and oil filter.

I would consider looking at the post#141 above TSB: https://www.audizine.com/forum/showt...1#post13631107

**mtaylor505** · 12-16-2019 12:05 PM

Originally Posted by wwhan

Pop the oil cap off and check if you smell gasoline, if so then maybe change the oil and oil filter.

I would consider looking at the post#141 above TSB: https://www.audizine.com/forum/showt...1#post13631107

Thanks wwhan. Changed the oil last week and it still did it the day after a fresh change. I'll take a look at #141 carefully. Thank you

**leeg0n** · 03-09-2020 06:37 AM

Hello all. I just wanted to tell about my experience with my Audi S7 (C7 2012). I hope that this will help those who are still struggling with the engine problem. So I have a custom tune (stage 1) and at first everything was fine. I installed downpipes and I had straight pipe without any mufflers only x-pipe in the middle.
At some point engine didn't start correctly. I had to crank it a while and press gas pedal to even get it to start. It didn't matter if it was 30 degrees or -5 degrees outside. Then I had this intermittent problem and in summer I had random misfires. Then after that I had idle problems, so when engine started normally I had rough idle, VCDS gave me misfires and told that fuel is too rich in both banks.

So some guys told that problem is in spark plugs, injector, others told that it is tune problem etc. So I remapped ecu back to original but nothing changed. It was so weird that in one day everything was totally fine, engine was running smoothly, started normally etc. and on another day it was a disaster.

Now I found one guy who looked my engine and told that problematic is one HPFP because it is leaking fuel to the oil. Oil had a fuel smell when we took oil cap off. He took HFPF off and saw that camshaft have also little damage (scratch on metal) because leaking fuel was "eating" oil below it. Next week I will get car back and can tell you if it helped or not.

**leeg0n** · 03-27-2020 01:55 AM

So workshop changed both HPFP pumps and now there is no problem with starting the engine or misfire issues.

**ichi d** · 07-29-2020 12:16 PM

I'm starting to have this issue and it's so random car runs fine and no codes. I do smell fuel in the oil cap so I'm going to replace both hpfp. Does anyone know the part numbers for the two hpfp? Are they the same or are there two different hpfp? Thanks.

**MaineAvant** · 09-07-2020 05:24 AM

Originally Posted by leeg0n

So workshop changed both HPFP pumps and now there is no problem with starting the engine or misfire issues.

Still going good?!

**ichi d** · 09-08-2020 04:44 AM

Just fallowing up, I replaced both hpfp with the latest revision and no more hard to no start issue. My13 92k km and it was on the original pumps.

**MaineAvant** · 09-08-2020 08:16 AM

Originally Posted by ichi d

Just fallowing up, I replaced both hpfp with the latest revision and no more hard to no start issue. My13 92k km and it was on the original pumps.

Thank you so much for the update!

**MikeG183** · 11-11-2020 09:17 PM

Thanks everyone for the info here. I recently purchased a 2014 S7 with 80k miles and have the exact same issue. Dealer was no help (other than confirming that the ECU update had already been done). And my independent shop was pretty stumped. First tried evap valve replacement, which seemed to help mitigate the issue. But still present. Then I bit the bullet and had both HPFP's replaced ($1500 parts and labor). Car runs much better across the board and have not had any trouble with starts so far (knock on wood). But have only had it back a day and will update if it happens again.

**V8TVT** · 12-05-2020 01:53 PM

I've had mine for 2 years (S7 2013, bought in 2018) both summers had hot weather/warm engine start issues.

Guy that sold me the car just had one of the HPFP's replaced due to the exact same issue, he was honest about it and believe it to be fixed when he sold me the car.

Anyway this summer I recorded a few videos of it not starting and finally got the Audi to investigate properly during it's service. Guess they followed one of the TSB's and both HPFP's were replaced (under extended warranty), so will see if it's cured next summer (and will report back too).

One extra (maybe related) thing, is even when the engine is cold/overnight etc, it still cranks a bit too long for my liking (~1 second) before firing up. I would expect it to fire up in like 0.1 seconds, but maybe that's just normal for this engine, or maybe cause all the fuel has evaporated from the lines and needs to be pumped back up from the tank which is my suspicion.

**Woodepic** · 01-29-2021 01:43 PM

Originally Posted by V8TVT

I've had mine for 2 years (S7 2013, bought in 2018) both summers had hot weather/warm engine start issues.

Guy that sold me the car just had one of the HPFP's replaced due to the exact same issue, he was honest about it and believe it to be fixed when he sold me the car.

Anyway this summer I recorded a few videos of it not starting and finally got the Audi to investigate properly during it's service. Guess they followed one of the TSB's and both HPFP's were replaced (under extended warranty), so will see if it's cured next summer (and will report back too).

One extra (maybe related) thing, is even when the engine is cold/overnight etc, it still cranks a bit too long for my liking (~1 second) before firing up. I would expect it to fire up in like 0.1 seconds, but maybe that's just normal for this engine, or maybe cause all the fuel has evaporated from the lines and needs to be pumped back up from the tank which is my suspicion.

Ever since you had the HPFPs replaced, did you have any rough starting? I'm in Canada, and even in our winters I'm having rough starting issues. From everyone else's reporting, it sounds like the issue lies in the HPFP, but I'm curious if you have still had issues with the new HPFP?

**MaineAvant** · 01-30-2021 04:16 AM

Replaced mine. I did pull them first and found them wet down by and passed the spring where they are not supposed to be. Replaced and haven't had a single issue since.

**Hofahome** · 01-30-2021 11:13 AM

Originally Posted by Woodepic

Ever since you had the HPFPs replaced, did you have any rough starting? I'm in Canada, and even in our winters I'm having rough starting issues. From everyone else's reporting, it sounds like the issue lies in the HPFP, but I'm curious if you have still had issues with the new HPFP?

There is a tsb that takes you through determining if the pumps or injectors are the cause, but you would need logging software like vcds. You could start with a good fuel system cleaner first though.

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**Woodepic** · 03-20-2021 10:55 PM

Originally Posted by Hofahome

There is a tsb that takes you through determining if the pumps or injectors are the cause, but you would need logging software like vcds. You could start with a good fuel system cleaner first though.

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Update: I followed the diagnosis criteria via the TSB, and verified the hpfp's to be the issue. I just installed the hpfp's and everything works great! Thanks to everyone on this thread, couldn't have fixed it without yall!