Need Help Diagnosing M4 Issues

[f82shawn]

Hello, I have a 2017 M4 Comp that I picked up a few months ago. Had left it stock until about 1000 miles ago, when I decided to get some vrsf catless downpipes, and a stage 2 tune through BM3. Everything was going fine with the car, no problems, and was ripping on it consistently. Then a few days ago, car goes into limp mode during a pull, followed by a CEL, and after I scan it, it comes up as a misfire on cylinder 4. No biggie, I suspect it was ignition coils or spark plugs, so I order a tune up kit through FCP Euro with the OE Delphi coils and OE Bosch plugs. The next day, I install the parts and re flash the car and clear the codes. Everything seemed to be running smoothly, but then when I went to turn on the car in the gym parking lot, it turned on, then shut off 3 seconds later, same deal 3 times over, until the 4th try it decides to stay on. Problem sort of stopped, but idle was rough for about 20 seconds when starting car cold, the shut off issue came up a couple more times here and there, but the car seemed to be doing it less the next day. Then, later in the day, the car goes into limp mode on the freeway, so I scan it out when i get home. I get hit with quite a few codes, instead of just a misfire on cylinder 4, it said it detected a misfire on cylinder 4, 6, 3, and 1, as well as code 120408: Boost pressure control, and 108C01: charge air temp. Flashed it back to stock and it seemed to be running fine, then flashed back to stage 2 and was running fine for about 45 minutes. Scared to drive the car again, trying to diagnose what could possibly be going on. Any advice would be appreciated, thank you.

[1heckinboi]

Have you checked the coolant level for the intercooler already?

[Busa1]

Could it be the plugs you used? Did you get the correct ones (1 step colder I believe) and gap them properly to work with a Stage 2 tune?

[krudmunk]

Try NGK 2 step colder plugs and gap them properly for your tune.

[f82shawn]

Update, put about 50 miles on since I cleared codes, car isnt having a rough idle or misfiring, but went into limp mode so i scanned it again. no misfire codes, but I have the ones that follow: 120408 (boost pressure control, shutdown as a follow-up reaction), 108C01 (charge air temp too high), 20A201 (charge air cooling system: coolant pump protective function active due to dry running).

[f82ryan]

Check your top mount intercooler seems like a code that it’s empty

[b_w.]

Mis fires are probably tied to coolant leaking. Likely need a new tmic. Look at OEM or if you want aftermarket go Wagner. Will want to change your oil.

[N1rve]

You need a new TMIC.

[Jmk508]

Perfect time to upgrade. Just installed a Wagner unit and fitment was great!!

[f82shawn]

You guys were right, checked intercooler reservoir and its definitely leaking somewhere. My question is once replacing it, how should I clean out any trace of coolant? Obviously flush oil and replace, but how else and where should I clean residue as I suspect I’ll find some probably in intake manifold once I pull the intercooler, and what should I use to clean. Cheers

[f82shawn]

Also as far as aftermarket solutions, is wagner best route to go? I know CSF has one for same price, and was debating the VRSF one as its 3x cheaper, but not too sure how much quality is sacrificed at that price. Any input is appreciated, cheers.

[gcant35]

I too am curious about the quality of the VRSF top mount ic, I've had one sitting in my garage for months I got from a buddy who sold their car. Haven't installed it yet since the OEM unit seems more than efficient in terms of cooling and IATs (until they leak).

[NSX2M4]

Originally Posted by gcant35

I too am curious about the quality of the VRSF top mount ic, I've had one sitting in my garage for months I got from a buddy who sold their car. Haven't installed it yet since the OEM unit seems more than efficient in terms of cooling and IATs (until they leak).

I'd rather just buy an oem one every 4-6 years TBH.

[N1rve]

Originally Posted by f82shawn

Also as far as aftermarket solutions, is wagner best route to go? I know CSF has one for same price, and was debating the VRSF one as its 3x cheaper, but not too sure how much quality is sacrificed at that price. Any input is appreciated, cheers.

Wagners or Mishimoto. If you live in a CARB legal state your option would be Mishimoto or another OEM. Though be mindful that an OEM one is 1/2 the price and if you get through FCP Euro, you would have lifetime replacements on that item.

CSF has been shown to decrease performance so I don't recommend it to anyone and I think this is also lacking a CARB #.

I have not heard too much about VRSF.