2017 GLA 45
18.5k miles
Stock turbo
AMS Intercooler
AMS Intake
AMS High Pressure Fuel Pump
Wagner Primary Heat Exchanger
Wagner Auxiliary Heat Exchanger
TurboSmart BOV
Tuned by AMS, running E85 fuel (full time)

I have been running the above setup since 13k miles, with no issues until now

Shortest version of the full story I can give:

Was on my way to get gas before going to Gridlife Midwest. Car was mostly fine, felt some slight hesitation on the way, but nothing bothersome. I was just under 3/4 full, filled up on E85.. go to start the car and it ran like crap. Misfiring, sounded like a Subaru, Check Engine Light flashed/popped on. I slowly drove myself home.

At the time, my cheapo OBDII reader said I had a misfire on cylinder 1. Since, I have bought a 'MyCarly' and have seen misfires on all 4 cylinders, sometimes just cylinder 1, sometimes cylinder 1 and 3... Always at least Cylinder 1. I have also gotten codes for "Injector Injection quantity adjustment for cylinder balances has almost reached the lower limit of at least one cylinder" (P1CF084). Also P030085 'Combustion misfiring has been detected', which seems to be a general misfire code.

I typically erase all codes, will try to go for a drive and see what comes back. So far, there really hasn't been a consistency to what codes have been thrown. Always a different combination of things.

Anyway, after my first issue, I replaced all spark plugs which seemed to fix the problem until I got into boost and the issue came back. I then moved coil pack 1 to 2, to see if the issue would follow and it did not.

I did a compression test and got 150psi on all 4 cylinders. The car does not smoke or leak anything.

Vacuum (AEM Digital Boost gauge) is the exact same as when my car was running fine. My wideband (AEM) will show the car to be running lien at the time of the issue, but honestly, my AFRs seem to be all over the place, so I can't really give a fair answer as to what the AFRs are when the car is experiencing this issues.

One day, while diagnosing, my car seemed to "Fix itself". No hesitating, misfiring, codes throw, nothing. I drove it for 4 days straight under all loads and everything was just fine. Then one day when I was coming home, I pulled in my driveway and my car seemed to hesitate and my CEL came back and so did the same exact issues as before. I let the car sit for 3-4 weeks after that out of frustration.

Just the other day, I decided to try to diagnose some more. I got the car started, warmed up and went for a drive. Everything seemed fine for about 15 minutes, under all loads. Then as I was coming home, I got my misfire back and the car started running like trash. I couldn't really give it gas, it would just bog down. I ended up getting into my neighborhood where I stalled out, which was a first. I waited, started the car and got about 20 feet before I stalled again. Waited some more, got the car started and was able to give it just enough to get into my garage. There it idled very choppy long enough for 'MyCarly' to get a read. Thats when it gave me the codes for misfires on Cylinder 1 and 3, the Injector cylinder balanced code and the general misfire code.

Today, I can't get my car to start, or if it does start, it sounds awful and barely stays alive. I can't give it gas or really do anything, it idles like **** and eventually stalls out. This is the absolute worst its been.

So I'm at a loss here.

Some things people have brought up:

- Replacing all 4 coil packs
- Changing out Crankshaft Position Sensor, which I did buy an OEM one and have it on hand, but I cannot for the life of me locate where it is. I know the general location, but can't seem to find it. (From what people have said, this is a common fault of our cars that causes a multitude of issues)
- AMS High Pressure Fuel Pump is failing or has failed (there is also history of these failing)

Anyone have any other ideas? Thoughts? Things to try?

 

It sounds to me like your issue is likely being caused by the aftermarket tuning you've had done since the car ran with no issues before the tuning. I would suggest taking your car back to your tuner and have them look into the problem.

 

Car ran great for 5k miles after tuning. All of my modifications I listed were installed all at once, got the tune loaded and had been driving the car for a couple of months. This issue only sprung about recently.

 

I still think it's tuning related because you had no problems with the car before it was tuned.

 

I'd hope so. The car was bone stock before the tune. Once I did all my mods, I was forced to get a tune, especially with the HPFP. Car drove like a factory car should before I did all the work and the car drove even better after I did all my work and got the tune.

I'm gonna be checking the quality of my gas today. If its fine, then I'm gonna be forced to find a way to data log the car send my ECU and logs back out.