16168625 BHAN modifications for TBI to TPI conversion questions>>

[EagleMark]

The reason I suggested switching to $0D is because so far all these PCMs can... no if you only have one injector driver we may have found a difference?

Also your BHAS was superseded twice to BLCR so that may be a better start.

Six, he was just advised on another forum that there is no need for resistor change? The TBI to MPFI doc clearly states:

Injector Drivers

Next you will need to change two resisters in the PCM. This modification is necessary to disable the Peak and Hold function of the injector drivers. The resistors are called sense resistors and sense the current to the injectors. The resistors have to be changed in order to run 8 MPFI injectors, 6 is OK but 8 puts too much current load on the resistors.

Port injectors come in two types: Peak and Hold (low impedance) and Saturated (high impedance). This modification only works for Saturated (high impedance) injectors.


You will need to remove the stock resisters and install a solid wire jumper in there place. It would be best to check with a electronics store, as to the best type of wire to use in this application. Another option is to salvage a couple pieces from some other dead electronic device.

Here's a picture of what your looking for.

[EagleMark]

May as well bring this back up here too... memcal mod!

dimented24x7 states in a 2006 thread:

There are three firing modes in the PCM: TBI/batch/bank fire. The memcal mod is needed to tell the injector drivers when to fire. The injector drivers for MPFI are software driven using the timer output compare lines. There is a hardware timer/flag in the MCU with its rate set by the memcal configuration that is used to trigger one of the two injector drivers at the appropriate interval.

Somewhere 1project2many said this is redundent as the Bit checked CFI/MPFI mode did the same thing?

So someone that could read code better then I could see what changes are made when 0x400B is checked?
Here are notes from $0D XDF, now between 2006 and now there was TONS of work done to these PCM dissasembly and masks from some great people. Like Deminted24x7, HaulinAss, 93V8S10, Fast305/355 to give credit from just memory

Title: CPI/PFI Mode

Location: 400B-Bit 0

Usage: Air Fuel Mode Words

Tips: To change between TBI and CPI/PFI injector firing strategies. Checkmark if you will be using Central Port Injection or Port Fuel Injection. TBI fires the injectors twice per crankshaft revolution. CPI/PFI fires the injectors once per revolution. PCM modifications are also required.

I'd like to know why I can run and tunea $0D MPFI without the Memcal mod? Actually if I add it the vehicle runs like crap?

[JeepsAndGuns]

The 16168625 will run $0D just fine. I have personally done it.

I also have a 16197427 based MPFI system. I simply followed all the instructions in the MPFI zip file linked above. I have the jumper wire installed in my memcal, because thats what the zip file said to do. I have not had a chance to try it without the jumper wire, as I have been tied up with work, and installing some headers and trying to get to the exhaust shop to put my exhaust back on. So I have been driving it very little lately. But seeing the posts lately about some saying yes you need it, and some saying you dont, has made me very curious.

[EagleMark]

The only thing that makes sense at this point is the jumper was needed before the bit for CFI/MPFI was found? Still does not explain why mine runs great without the jumper and horrible with...

[JeepsAndGuns]

And mine seems to run great with it, but I have never tried it without it. So it makes me really curious.

[Six_Shooter]

The only thing that makes sense at this point is the jumper was needed before the bit for CFI/MPFI was found? Still does not explain why mine runs great without the jumper and horrible with...

Sure it does. You've tuned it to run with injector pules w every DRP, instead of with every other. You need to re-tune when the jumper is added, because the injector firing frequency has changed.

[bybyc5]

Thank you all for the input!
I appreciate your patience with me!


I have 2 spare PCM's. One is set up with Craigs G1 and ziff and I have a few chips I got from him as well to play with. That's whats been running my truck for the past 2 years or so.


I think I'll get another G1 and Ziff for the second PCM so I'll have 2 usable PCM's and leave the OEM one alone.


I'll do the memcal jumper in one and not in the other, and go from there. And bypass the resistors in both? Easy enough to solder in a jumper over the resistors, and later snip a set out of one PCM and see what goes?


I am still cloudy on the “ASYNC SHORT BPW OFFSET VS. BPW” Looks Like I leave this set to off for MPFI.


The MPFI definitions XLS is for version 4 TunerPro, and $0E. Try and match up what I can? I am using TunerPro V5.


I am actually a new user to TunerPro, as I have been using TunerCat for years. The file definition for my $e6 did not have Injector offset parameters...so I downloaded TunerPro and donated. It has a lot more parameters to look at.


This is getting good!
I have tuned a couple different cars PCM's and Ecm's. (LT1's and L98- MAF systems) I have a moderately modded LT1 Formula that runs well on the Tweaked 16188051.
I do not know how to decipher code though. I get lost and covered up quick there.


I have never tried to switch injection systems and re-tune the same PCM for the new system.


And no real speed density experience really yet. I can see where a program like “VE Master” would be nice. Found references to an old program that Craig wrote years ago, but can find no downloads for it.
Think it was called VE PHD or something.


I can see I may foul a few plugs to get it running decent enough to drive, data log, and tweak! That's fine.


Again, Thank you all so much for the input...I still have questions, and am digesting what you have given me.


The dead links I run into from old posts is what is frustrating for someone digging up old information.


Thank you,
Keith