How long will it take my custom tuned ecm to calibrate to my engine? - Third Generation F-Body Message Boards

73duster · 06-13-2009, 02:25 AM

I just installed a 383 crate engine with first fuel tpi setup. The engine is 10.5 to 1 compression with a comp cams high energy 218 duration 484 lift(with my 1.6 rockers) and 24# injectors. It dynoed @ 386hp and 485ftlbs of torque. It also came with a custom tuned ecm that was setup for this particular motor. It is exactly like the stock computer except the chip or (memcal?) was taylored for my setup. I was told by the engine builder that it would calibrate itself and run better after i drove it for a while and should make a little more power in time. The car runs ok except there are a couple of dead spots just off idle at a couple of different rpm points. Sometimes when i let off the brake pedal the car lurches forward and surges as if it wants to accelerate and stop repeatedly. Then i tap the accelerator lightly and it smoothes itself out. It feels as if the fuel map is slightly off a certain rpm's. Does the ecm adjust itself or do i have to have someone tune it. The car sounds great and has a decent chop for the cam, but i hope the throttle response gets a little better. It does'nt feel like it's off by much, how long do i have to drive it around for it to get better? What am i missing?

Drumer919 · 06-14-2009, 01:25 PM

Its not going to be able to fix that, about the only "learning" it does is of long term fuel trim. You need to get it re-tuned.

Ronny · 06-15-2009, 04:15 PM

Drumer is right. You should return and allow the Dyno operator to tweek it in those specific areas as needed. All to often the Dyno gets the WOT A/F right but does not spend the time on general drivability area of tune.