If the 7747 / 8746 ECM cannot run 8 saturated injectors, then how does the Edelbrock MPFI conversion kit work?

Does it have a plug-in of some sort? Or is it a matter of injector ohms and the code in the chip they give you?

 

The chip that Edelbrock gives you will have the corrections to run the 8 injectors. As I have no idea how chip programming is, I cannot tell you just how.

I have looked into this kit myself, but came out with these results

Consider this.....

Straight from HOTROD August 2002 issue, the kit alone only delivers 21horses to a bone stock 350TBI. Now I do not know how well it will work for a modified engine, but 20 horses is about what you would get from a swap to TPI. The price is about $1000 even from Summit or Jegs for the MPFI kit, and you can get a complete tune-port system for less than $600(If you know where to look). I was considering getting the MFPI, until I realized that its probably cheaper(and more tunible) to go TPI. I, myself enjoy my TBI, so I don't slam them at all. I have achieved high 13 second ET's with my modded TBI unit. Not bad for a Daily driver.

But in all seriousness, TPI would be cheaper, better, and more people would be able to help trouble-shoot any problems that you may have, because not many of us third-genners have it.(Especially when it comes to programming the chip.)

 

The stock fuel pump on a 350tbi only pumps 15psi, the Edelbrock kit requires 42psi, so your going to have to go through all the B.S. to install a new fuel pump(IN TANK=PITA).

 

Of course the ecm can run 8 saturated injectors!!!
From what I've gathered, 8 sat. inj.'s have the same impedance as 1 low ohm TBI peak and hold.
TBI fires injectors twice a rev of the motor, that's both injectors. TPI and other batch fire setups fire the injectors once an engine rev. So by hooking up only one of the drivers on the ecm to the 8 sat. inj's you'd have a relatively normal batch fire setup. The only problem is the that ecm was never ment to fire these injectors so it's a little flaky in tuning above 4500rpm. It had a lot to do with timing but when I tuned a friends 90 pickup with a zz4 and this MPFI kit I couldn't get the fuel to be anywhere close beyond 4500.

 

Thanks for the replies.

Hehehe, I'm not thinking about buying the Edelbrock MPFI. I'm putting together my own. Weiand sells a couple different MPFI intakes, and I have 4 sets of 19# injectors and 2 sets of 24#'s sitting around. So if I could run an MPFI system off my 7747 for minimal $$ I will.

If I do I was going to buy the 255 lph fuel pump designed for the TPI f-body. I think the pump is a little longer but that's no big deal. My gas tank also comes out real easy, assuming it's not full @ 27 gallons !!

I also have the Edelbrock MPFI bin. And tuning above 4500 rpm might not be that tough for me since I max out at 4800-5000

JPrevost...when you say you couldn't get the fuel close above 4500 rpm, do you mean the BLM was all over the place? Or was it too rich / lean altogether?