RedWing

STFA'd and found that many M box X chip users experience hesitations in the mid RPM range. However, many others have never experienced this. I can't seem to see any trend concerning who sees it and who doesn't (my A box car had no such symptoms).

People who have had this - have you had any luck tuning away the hesitation?
This little gremlin is driving me crazy. New samco tbb, new coolant T sensor and new 710N dvs. Logged boost - requested = actual, seems OK ~1-1.1 bar. MAF air flows seems good, 250-270 g/s is the max at WOT in 3rd. Hard acceleration is fine, smooth; but medium throttle in traffic has many hesitations from 3-4K RPMs. Car is especially sluggish when it is first started in the morning. Another intermittant symptom is hard decelleration when I let off the gas for a shift. STFA says EGT sensor, but others have said this is just the way the code is for GIAC. No EGT sensor code in my case.

Put in stock box, smooth as silk.

No codes except one warm-up catalyst code (bank 1). Could this be an O2 sensor that is causing the problem? STFA - most say to ignore this code with aftermarket dps.

LaserAvantS4

have you tried boost controller? my MBC seems to eliminate that

RedWing

Nope - I need to do some research on MBCs, I guess. Any other solns out there?

S4saken

... so I bought the Dahlback Stage 2+ ECU. I've been running it for a few days now and it is as smooth as silk. Subjectively, it feels as strong as X even without the steep boost ramp-up, so I don't see throttle cut even with my MBC cranked all the way up.

I plan to log some FATS pulls as soon as the roads clear up.

What's nice about the Dahlback is that they ask you exactly what you have for intake, exhaust, etc and tune the code for your setup. If you change anything, they will update you for free.

Ed

RedWing

I don't know enough about chip tuning to know why the H/M box should be like this but not A box. That's why I am looking for some other root cause with my car, because it doesn't make sense that the code can suck for one box and be great for another.

villainS4

my M box X software, unfortunately that was long gone by the time I met Jeff.

RedWing

Thanks.

Swank4

and I switched to AMS because of it. My guess is that X has this problem because it runs very aggressive boost/timing early on. While running boost very early helps with power and low-end, it also makes it less reactive to throttle inputs.