$0D MPFI, base timing and injector timing
Well, ever since I converted to MPFI, I have been battleing a problem with my AFR all over the place. Some of you may remember my thread ( http://www.gearhead-efi.com/Fuel-Inj...-created-equal )that went on forever. I tried a different o2 sensor, tried chaning different things, I added, enabled, and tuned a MAT sensor, which helped a lot, but AFR was still all over the place.
I had figured it had to be the fact my wideband was in the right down pipe, and my NB was in the left down pipe. So I recently installed some headers and moved the WB to the left down pipe and placed it a couple inches in front of, and slightly offset from the NB. Well no major changes, AFR still all over the place. So I decided to try something. I remembered seeing in several posts, Mark talked about always having base timing set to zero, because injector timing is based off the DRP's.
I have had my base timing set at 10* ever since I swapped to fuel injection. Reason being my engine would barely run at 0* timing, definately would not be driveable. So I followed advise from a couple places and set it to 10* so if I ever went into limp home mode, I could drive it. Everything worked great with TBI, it wasnt untill I went to MPFI that I started having problems.
Anyways, today I drive it till its warm, and reset my base timing to 0*. It just barely ran enough to set it. I changed the bin to match and burnt a new chip. Take it for a spin and wow, now my AFR is now where its supposed to be, only swings what is probably normal. It actually seems to run just a little bit smoother too. Also, my AE was now going lean if I hit the gas, so I had to spend some time and add a little AE.
I'm guessing with TBI, the injectors were far enough away from the intake valves for it to not really effect things, but with MPFI and the injectors being much closer to the valves, it was enough to throw things off?
