Just out of curioustiy

[tolow4phathoes]

Is is possible to run a 7427 PCM In MPFI Mode to run 8 injectors, using a home-made injector harness,run some ford injectors I have laying around. Run this intake
http://www.jegs.com/i/Edelbrock/350/...arentProductId use a lsx throttle body, top off with a maf unit aswell? Or am I just a lil over my head? I plan to in the very near future, do a nasty 500hp 383 stroker build and would love to have the ability to stay efi and be able to tune each individual cylinder to its peak. As well the offering of also being able to run a 4l80-e and fine tune just from my finger tips. shift points,firmness,etc...

[dave w]

The quick answer is yes, the 7427 can run 8 injectors in MPFI mode. See attached .zip file.

dave w

[JeepsAndGuns]

I am running a 7427 in MPFI mode.
The 7427 does not allow you to tune each cylinder individualy, as it fires in batch mode.

[tolow4phathoes]

I am running a 7427 in MPFI mode.
The 7427 does not allow you to tune each cylinder individualy, as it fires in batch mode.

Are you running MAF or still Speed density? Is the swap worth it in your opinion?

[EagleMark]

Is it even possible to run the MAF code with MPFI?

[JeepsAndGuns]

Are you running MAF or still Speed density? Is the swap worth it in your opinion?

Its still speed density.
Is it worth it, humm, hard to say. But I would probably say yes, in my case anyways. I did notice a slight power increase over TBI, however I also changed intake manifold styles and throttle body styles. The intake is completely different from my old one. My old intake was a edelbrock 4v dual plane carb intake, and the new one is a edelbrock single plane made for MPFI. So I do not know how much of the power came from the different intake/tb and how much came from MPFI.
There is some tuning hurdles you have to jump through to get it running right. Some values that must be put in correctly, and it completely changes the way fueling is done, so everything will need readjusted. Some of it is just trial and error. I am still tweeking on mine.


Mark, I thought I remember a thread one time where you were tuning or helping to tune a 7427 MPFI system with a MAF? For some reason I remember you were having a problem with fueling at startup?

[EagleMark]

Mark, I thought I remember a thread one time where you were tuning or helping to tune a 7427 MPFI system with a MAF? For some reason I remember you were having a problem with fueling at startup?

It's S/D MPFI. I've never done the MAF but all the reading I've done on it was all TBI MAF...

Seems a lot of guys have issues with fueling start up... maybe all but some don't notice quirks, I do! Anyway most of the issues I had were trying to tune Accell injectors before they had injector data. I'll never, ever do that again! To many tweaks and it's all a trail and error guess.

There is one error in the MPFI code I found that includes MAT spark Bias to Idle/Off Idle spark tables when MPFI is enabled, so you loose 10 degrees timing! I like leaving spark bias alone for complicated reasons or to avoid complications. In this case we had not installed MAT yet so I removed it and got my 10 degrees back! No one could find why in code?

[dave w]

There is one error in the MPFI code I found that includes MAT spark Bias to Idle/Off Idle spark tables when MPFI is enabled, so you loose 10 degrees timing! I like leaving spark bias alone for complicated reasons or to avoid complications. In this case we had not installed MAT yet so I removed it and got my 10 degrees back! No one could find why in code?

That is extremely useful information!!

dave w