Trash

Good to know. I seem to remember he had a few, but not all. With enough MEFI 3 tunes floating around it would seem easy to load a big block tune and scale back the BPW table. All the other scalars and constants rarely need to be touched for initial tuning.

On another thought, assuming the 'new' 383 runs too lean for his taste with the stock injectors and fuel pressure, rather than jack fuel pressure up just install slightly larger injectors. Say go from a 26 lb injector to a 32 or 36 lb injector. Timing table and all the others scalars could remain untouched and the larger injector could be sized to the increased displacement. Conceivably the tune would never need to be modified.

articfriends

Funny story about "tuning" a 5.7 TBI: A good friend whos retired had a fishing boat, had a 5.7 tbi mefi3 , sits down under floor with giant hatch you remove. Calls me up all in a panic, says he has boat sold but suddenly it wont run right and guy wants his deposit back. Proceeds to tell me the most convoluted story. So he tells me he always ran a certain prop and it never quite revved where its supposed to, guy was buying it so he put a slightly smaller prop on it to "impress" him, proceeds to tell me that it hit the rev limiter and broke up a little and has never ran right since then, they been paying to have it worked on and seems to be no fix. so he says they took it to a local marina next to the boat launch in a nearby town, they determined it needed a fuel pump and charged him 1000+ $ to change pump and scan it. So after they did that, it ran EXACTLY the same. So they told him that these efi systems have a "hard" rev limiter and once you hit it , sometimes you have to have a efi guy go in and clear it (you cant make this **** up). So, I grab mi tuning laptop, mefi burn cord, some hand tools, a few sensors etc and meet my friend at docks, on way there I call bob at mefiburn and ask him if they ever figured out any unlock codes for any small blocks as Id like to pull the tune off for future reference, tells me nope. So I get there and I take one look at the motor and see the tit for the map sensor is broke off and WTF, the hose going to map sensor is plugged onto a exhaust riser on a little barb. I laugh and tell him well, this will be a two minute fix, I wont even need to scan the data with laptop. I pull out a new map sensor I brought, I install it, attach the hose back to the vacuum port on motor and I ask him who the fawk has been wrenching on this?? proceeds to tell me the fuel pump, hard rev limiter story. Then he tells me oh yeah, the changed the riser gaskets two. So the incompetent marine "tech" BEFORE it had problems did riser gaskets, broke off the map sensor, attached the signal hose to some random fitting on a exhaust riser .
So, new map sensors in, we take it for a spin and NO, its NOT fixed, its back firing and breaking up under a load. So I ask my friend : tell me EXACTLY everything thats been done to this, every detail. He says oh yeah, my neighbor was trying to help two so he pulled the throttle body off and "cleaned" it. So I plug mefi scan in, I sweep the tps and lo and behold its frozen in time, does not do anything thing as far as voltage change (should have done that to begin with). So I ask him, did you guys take the tps off, he says yeah, either the neighbor or the guy at marina did. Well, they put the flat part of shaft in it wrong and ripped the guts out of it.
So, we leave the boat at dock, run to a auto parts store, buy a tps for some TB 5.7 version for a Chevy van or something and boom its fixed. I ask my friend, you PAYED the guy at marina next door to scan this and he didnt see any of this, unbelievable!

liberator221

Amazing story. Can’t believe number of people that hack their way through, lie to customers, and steal money. Sad.

articfriends

What I CANT believe is they misdiagnosed the fuel pump and failed to see obvious problems on engine and didnt see them scanning it either Im not some
merc certified tech' but within 15 minutes I had it completely figured out, LMFAO!

Trash

Classic. Glad you helped the guy out!