Good day All,
I have a 2005 350Z Roadster 6 speed manual and a vortech supercharger on it. Last year after storing it for winter (WI) I started unit up and ran as normal. I didn't touch the car for about a month and the battery was dead. I put in a new battery and car starts right up.
During cold or warm temperature the engine seems to cut out or stumble and jerk the car. If it does it long enough it will put it into limp mode. I run a scanner and I did get no codes. Tried another scanner from a friend and same think with no codes. I clear the no codes
(I know seems dumb but gets it out of limp mode.) I can Throttle with no load and seems to be fine. I called Vortech to see with the battery being completely dead that maybe it wiped out the timing box supplied with the supercharger kit. They thought highly unlikely but
gave me Split Second contact info and called them. They gave me a few ideas and tried them. I do not see any vacuum leaks at the moment, and I am wondering with the battery being dead is there any type of relearing that the car would need that I should try? I have for giggles
replaced MAF Sensor as the garage where kept was dusty. Also it has just less than a 1/4 tank of 1.5 year old gas. Just looking for any help or ideas, I have been searching the web and seems like a few have similar problems without stating a fix.
Thanks for any help provided.
Matt

 

If the battery was dead for a long period of time, then the learned values on the ECU will be lost, usually this will cause the "service engine soon" light to come on. I know because this just happened to me as I had the battery disconnected for 3-4 weeks while I was doing an infotainment installation. Perhaps this occurred because the battery voltage dropped very low when I hooked it back up for brief periods of testing during the install. Before I took it out for a test drive, I recharged the battery and brought the voltage from 11.6 to 13.1 (Battery is fairly new and health was fully restored). The code it threw when I put my scanner on it was P0603 - ECM Backup Circuit. Even with the code present though, the car ran great, no issues. I simply cleared the code when I got back from my test drive and haven't had an issue since.

Your situation is a little unique since you're running FI with the Vortech piggy-back ECU unit. Was the new MAF an OEM unit? Keep away from the aftermarket ones. Without seeing live data, it's going to be difficult to sort out what's happening here. It's possible the Vortech inline fuel pump booster is malfunctioning. Have you checked for signs of rodent damage? I assume the vehicle was stored all winter long and up in WI, I bet rodents nesting in cars is a big problem.

Summarizing...
Under load, either hot or cold temperatures, the engine starts misfiring/stumbling.
Without load (neutral) the engine revs without issue.

Cheers!
-Icer