2017 A8. Mods, Kooks long tubes and X-pipe (no cats), Halltech RZ induction, ported Mamo throttle body, and Fasterproms expansion tank. I had the car tuned for 93 octane. Now when I accelerate hard the engine completely shuts off and then comes back on again between 4000 and 5000 rpm. It does it over and over again. It will rev like it is going to shift just before it shuts off. It is instant, like complete fuel shut off. It does this even when accelerating slow also.


I have HP Tuners so I can record it while it does this if someone here is willing to look at it. I would have to know which channels to record though.


Thanks for any help with this.

 

Did the tuner even road test it before giving you the keys back? I would not push it. Something is way off on the tune.

 

Whoever "tuned" it needs to FIX it!!!

 

They said they did but I doubt it. They gave it back with scratches on the door and the door sill. Couldn't even wipe the greasy fingerprints off. They had to get ready for an open house the next day. I have another thread about that in the General Discussion section.

 

I am mad and it is not even my car. Anyway, you may want to find another tuner altogether since it sounds like your are at more risk by continuing to use them.

Since you have HP Tuners already, if it were me, I would go back to the base tune and start over. Unless I am missing something, with your mods you really just need to disable the check on the O2 sensors since you have no cats (so you don't get check engine light) and dial in the MAF airflow portion of the tune for the Halltech intake. The base tune may even adapt enough on its own based on how much additional airflow you are getting through the Halltech intake. When I installed my intake on my 2002 Z06 it went lean by about 18% but the MAF could still adjust and add fuel as necessary without throwing a code.

The way you get a little more power from the tune is by optimizing the spark timing and leaning it out a little bit while in power enrichment mode, which requires a wideband O2 sensor to set properly. I would leave these settings stock for now until you get thing stable. If you get a wideband 02 sensor installed on your long tube headers then you can start messing with the spark timing and power enrichment tuning. You really need the wideband to see your AFR while at wide open throttle. That is what they are supposed to do on the dyno for you.

Do you know if they were making any changes to the transmission tuning? The only change I would make is disable AFM (V4 mode) in the tune. This is not actually a part of the transmission tune but by turning off AFM you may be able to prevent the dreaded A8 torque converter shudder.

 

The disabled the rear O2 sensors to keep the CEL from coming on. They said they did trans tune but I don't know what they did.


I took it in for trunk service TSB this morning and ran it up to redline in 3rd with no problems. This really has me concerned now. Yesterday I may have been in 4th or 5th but I doubt it, was at about 90-100 at 4k when it would shut down.
Tuner said that the low side fuel pumps on these car vary significantly on how much fuel they can provide. It is a mechanical system so I don't understand why they would be so much different. I will attach the e85 dyno and the 93 dyno.

 

Oh, it looks like you are supercharged. I missed that. Z06 or aftermarket system? I wonder if you are starving for fuel. I am not that familiar with supercharged setups but if you add more air then you need more fuel so you need to make sure you fuel pump and injectors are up to the task.

 

Please post the tune file, and please datalog the event and post that as well. At that point, you will have peaked the curiosity of people such as myself, Higgs, T/A, Chris Crawford and numerous others. I would be cautious using any tuner that does not respect the appearance of your ride. Scratches and dirt likely reflect the tool doing the “tooning”. I would cut my losses and hire remote tuning help from a Pro if nothing else. I tune but these things are a bitch in a lot of areas, so I reached out to Chris Crawford at Crawford Racing and I look forward to continue working with him.

John

 

I don't think it would be proper of me to post someone else's tune on the WWW. I have sent the file off to a competent source to see what can be found.


What is remote tuning? Would that be without a dyno?

 

Correct, they would provide a base tune and then you would drive around and collect data logs and send them back. The tuner modifies the tune based on the data. Rinse, repeat, rinse, repeat until the data in the logs look good and the car is driving to your liking.

 

Feel free to send files for review to chris@crawford-racing.com if you need help going over this stuff.

 

Update on this. The cutting out seems to be from me and my washing techniques. I use a pressure washer to clean up in the front end so I think this is filling the aftermarket intake with water and then when I step on it the vacuum sucks the water up the pipe and hits the MAF sensor and sends 100% to the computer and it shuts down (or whatever happens to the resister wire in the MAF when water hits it). Happened two more times after being at car wash. RPM that it happens at keeps increasing meaning there is less water in the intake track after each pull. Last time to the car wash I hit it once and it shut down, let it sit in garage for two days and all is well. Seems the extra open A frame can allow water to settle in the intake before the filter. I have Haltech RZ.

 

I think the Halltech RZ has caveats about driving in the rain on their website....