I started getting an 16197427 ECM together for 8 MFPI (port) injectors and found that the commonly used Fairchild HUFA76429P3 are still discontinued and there is no direct replacement for them. After some searching I ended up choosing the HUF75639P3 devices. They are slightly better, but have a higher turn-on threshold (gate voltage). I figured I would post here in case anyone else is doing the conversion. I will measure the gate voltage on the bench later on to see if the P&H drives the FET hard enough to generate the necessary gate voltages. I came across this thread: http://www.code59.org/index.php?opti...5234&Itemid=38 I did not chose the IRF part because of the turn on/off differences and the large gate capacitance. I think the HUF 75639P3 is a better choice for this application.

Hey Junk,
Educate a layman, are you saying that this FET switch is necessary to properly drive 8 sats in pfi batch mode on the 427?
Thanks

The 427 ECM will operate 8 saturated injectors fine, but you need to remove the sense resistors to make it 100% reliable. You can leave the .1 ohm resistors in there but it may or may not fire the injectors correctly. The FET driver is not required for 8 saturated injectors.

Got it! i knew about the resistors, I just thought there may have been a new hardware mod discovered to use on a MPFI app. Thanks

Junk,

If you are still looking for the HUFA76429P3, Detroitturbo still has them.


http://www.detroitturbo.com/cart/pro...roducts_id=134

I would give him a try. He said he had tons left a couple of months ago.

This is interesting.......I have a 1993 Z/71 with this PCM, and am in the process of negotiating a deal for a RamJet 350 intake setup to install on the Vortec 350 I have in it. Was going to use the MEFI4 controller, but if the 16197427 in the truck will control/drive 8 injectors, this will be better than what I was considering doing, which was using the MEFI4 for the engine and trying to construct some sort of piggyback harness to allow the '7427 to control the transmission.

Gonna keep an eye on this thread....

You should search HaulnA$$'s posts on these boards for info on this. He is the Godfather of these PCM/MPFI mods! I have found essential info for my project. Good luck

Just wondering how you made out with the Ramjet 350 with the E-trans controlled by the 427 ECM. Dimented24x7 pioneered that ECM and has provided a ton of information in another thread.

Hey junkcltr, just wanted to throw this out there, dimented24x7 has been rewriting the $od code maf for specific mpfi control, the sd code is still there and will be functional so it would still be like the traditional od code also. He is doing it right now. I will talk to him about posting it or starting a new thread about it. He was helping me with it for my mpfi setup and he decided it was time to clean up the code for mpfi. I am pretty sure all the e trans code is still there also. Just wanted to give you the heads up.

It would be nice to compare how I came up with the MPFI injector constant math/settings. I also remember the CPI/TBI bits taking a little while to figure out also. Then there was the settings for the EGR and stuff. Some of the tables were zeroed out in the TBI code. I think in the end I started with a CPI bin and modified it for MPFI instead of using the TBI bin as a base. It would interesting to compare the bins.

EDIT: I am running it with a 4spd right now so I haven't done the E-trans tune learning curve yet. The adaptive spark for the 4spd was something new for me though.

Did you say he was re-writing it to work for MPFI? I have been using the CPI mode and it seems to work fine. I did add a jumper wire to the MEMCAL to fire the injectors every 4th DRP though.
I am curious about the specific re-write for MPFI.

Yes it was a specific rewrite where you wouldn't have the memcal mod anymore because the inj events can be software controlled. Also MPFI when enabled is tied to other routines that are meant for tbi and he has been meaning to rewrite to make more of a true MPFI code. It can be better than what it is right now is what demented told me. For example the accell enrichment and startup routines could use revising for standard MPFI. I think he was using some code or ideas form the newer 411 pcm's. Most likely when the code is finished and I have it running successfully on my car we will post it up here for everyone, I don't see why not.