Hi guys!
New to this forum but been around the automotive world a while. Bought a new 2007 Mustang GT and over 2 years turned it into my version of a GT500. Aside from the body kits, hood, nose etc, I also worked on the powertrain & suspension. For the engine I bought a Roush stage 2 supercharger running about 12psi of boost from the new 2300 Eaton TVS rotors. When first installed it ran awesome and ran that way for 2 years. Since the car never sees winter much less rain, I store it, and bringing it out last year I ran into driveability issues. Since I could not get much help from Roush in Plymouth Mi, I purchased the HP Tuner VCM Suite and decided to have a go at what was happening. I even had Roush reprogram the PCM again, just to verify the calibration file was not corrupt, and it wasn't. I doubt the engine strategy is the issue, much less the tune, but I needed a powerful program to tell me what the PCM was seeing and what it was doing. In short, under partial load and low boost, the engine backfires through the exhaust as if it is running too rich. I replaced the obvious things from suggestions by Roush (MAF, ETC TPS, all 4 Narrowband O2s and spark plugs) but no change. I already have a boost gauge, wideband O2 system and fuel rail pressure senders. Due to Roush locking out the tune, I cannot read or edit the tune, which I was kind of ticked about since that was part of the expensive package.
However, I have used the VCM scanner to grab a bunch of run time data to show me what was happening. I am currently setting up a slightly better triggering system so I can tell within the plots when the engine backfires. In short, from preliminary data, it looks like the PCM is retarding the ignition timing to 0BTDC to even 5ATDC, and that is when the backfire occurs (sounds logical). Question is why, and what should I look at/for.
2nd question is does anyone have an unlocked supercharger tune for a 2005 - 2008 Mustang 3 valve 4.6L that I can view and play with? I purchased another PCM to program to my VIN so I can edit my own tune but would rather not start from scratch. Since HPTuners could not open my locked Roush tune and Roush would not send an unlocked one, not much choice.
I have a pretty good clue as to how engines and electronics work, based on working on cars & engines for 30+ years and being an automotive electronics engineer (I actually designed the hardware for my Ford PCM) for 25+ years, and I have done some side work tuning to practice plus hang out with the engine calibrators to learn. This issue throws me a little since I cannot figure out why the PCM is doing what it is. The Knock sensor amplitude does not go goofy right before or during the event either.
so, for the newbee to the board, HELP!!!!!!
Thanks guys for any input.
One other thing, attached is the tune from my Roush programmed PCM. With my VCM Editor I cannot open this. Can anyone else unlock it? I really appreciate you guys even reading my post.