NO PC - Mega Squirt/Mega Tune, never ending issues Options

[Scott S]

Hi All -
Does anyne have a megasquirt/megatune FI set up that actually works... at altitude?

My brother has been building a big bodied audi S-4 for thre years. As of today the car has less than 1000 miles on it over that time. The car is blisteringly fast - it dynos between 550 and 600hp at the crank. However the megatune management system is so unreliable/unstable that the car will run great for an hour, then start doing things like randomly shut itself down, or drop a cylinder for no reason. The guy who is the go to guy back east actually reccommended that he set his idle to 1500+ rpm's to keep the car from stalling when the AC is turned on. Other than that, the usual response is just to wait for the next upgrade. The mechainic who is doing the build is fantastic and just as pissed as any one over the issue.

The lower elevation guys have no issues, it only seems to be affecting those at higher altitudes. Its like they never tested the system anywhere above sea level.

There have been a few threads on the MS system on our board, but even after searching, I could not find where anyone was ever beyond the point of "well, there are some issues, but I will work them out later". Just curious if anyone has actually successfully installed a fully operational system.

Thanks - sorry for the book...
Scott S

[Scott S]

Here is what he just sent me:

I appreciate it, but my issue is the interface with OEM electrics and devices, so they most likely will not have similar experiences as it's S car specific. This is MS on steroids, albeit wimpy ones. we are fighting consistency in the ECU talking to the OEM bits, and certain bits falling off the radar unexplainably and then popping back up. The signals get lost, so it's a combo of the system and almost 20 year old wiring. ground placements seem to make a huge difference, etc. My injectors were not being talked to correctly, due to an impedance issue so the pulse width was all over the board. It's fussy, I don't like fussy.
FYI, ECU is in the car - probably two feet from the coil packs