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Thread: 16168625 BHAN modifications for TBI to TPI conversion questions>>

  1. #1
    Fuel Injected! bybyc5's Avatar
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    16168625 BHAN modifications for TBI to TPI conversion questions>>

    Finally getting around to my TBI to TPI swap in my 93 K1500 (383motor) 4x4 – 4L60E
    16168625 PCM.


    BHAS AND BHAM are the two stock bins I have to work with. UsingBHAN at the moment. The OEM PCM is BHAS. I haven't pulled the chip to read it yet, however I have been running the BHAN (spare PCM) in the 383 with stock TBI and some bin tweaks for the 383 for a couple years with no issues at all.


    I noticed these two bins are not listed in the sticky http://www.gearhead-efi.com/Fuel-Inj...Information-E6


    If anyone wants the stock BHAN, I can post it.
    The BHAS I haven't read out yet, but will if anyone wants it.


    Using TunerPro V5, $e6 file definition, and XDF E6_TPV5_v250.
    I am more familiar with TunerCat, but their $e6 file definition is lacking injector offset settings.


    I have a couple questions about PCM modifications.


    1- I have read here and other places the peak n hold resistors have to be bypassed or shorted. I am OK with that. Just solder in awire across the individual resistors?


    2- Also read about a memcal modification to get the injectors to fire every 4th distributor pulse. Isn't this for the v-6 4.3 PCM ?
    My PCM is already a v-8, and the injector timing firing should be OK as it is? It should be already firing alternating inj-1 then inj-2every 4th pulse, correct?


    3-In modifying the bin for the new injectors, I understand the injector voltage offsets, and have made those changes for my 24lb. injectors. FMS M-9593-LU24A.


    A - Question is how to calculate the changes for Crank BPW vs Temp?


    B – How to set BPW multiplier vs fuel pump voltage?


    C – What is, and how to set “ASYNC short BPW offset vs BPW?


    Any other fields to change for my initial start up?


    I know there will be many tuning tweaks to get it running efficiently, and I look forward to these. And learning as I go!!


    Wonder why there is no MAT sensing devise in this system? How is this calculated?


    Wonder why the GM TPI bank fire is 1357, and 2468, when the TBI intake is segmented to feed 1467, 2358, for inj-1 and inj-2 ?


    Thank you!


    Keith
    NE Tennessee

  2. #2
    EFI GearHead ! EagleMark's Avatar
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    Most of the setup can be answer with the documents in the zip folder here:
    http://www.gearhead-efi.com/Fuel-Inj...ull=1#post2855

    Look around the above thread for MAT installation.

    As far as the jumper memcal we have some threads here talking about how it is not needed when the bin is changed, check CFI?MPFI bitmak. I running one without and others say it is needed... so?

    You may be able to start with an $0D bin in your PCM, just make sure it is same year as your truck/transmission. There are changes from 94 to 95.

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Super Moderator Six_Shooter's Avatar
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    From what I understand all TBI systems (in the same ECM) have the same hardware resistance, and cyl number is set in the bin only.

    When going to MPFI, there are different resistances based on cyl count, that set the injector firing scheme.

    TBI fires twice as often as MPFI and this hardware change makes that work with MPFI. Anytime I've tried to run a TBI ECM on MPFI without a change a such would not run correctly.

    In reality the MPFI firing is 12345678. All injectors fire at the same time, at least when using ECMs original to MPFI. I haven't verified if this changes when using an MPFI converted PCM, such as the '7427 using $OD.
    The man who says something is impossible, is usually interrupted by the man doing it.

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    Fuel Injected! bybyc5's Avatar
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    Quote Originally Posted by EagleMark View Post
    Most of the setup can be answer with the documents in the zip folder here:
    http://www.gearhead-efi.com/Fuel-Inj...ull=1#post2855

    Look around the above thread for MAT installation.

    As far as the jumper memcal we have some threads here talking about how it is not needed when the bin is changed, check CFI?MPFI bitmak. I running one without and others say it is needed... so?

    You may be able to start with an $0D bin in your PCM, just make sure it is same year as your truck/transmission. There are changes from 94 to 95.
    Thank you for the link. The flag/switch settings are a great help, Thank you!

    My truck is a 1993 K1500 4x4.

    As for the $0D bins, I am unsure about using them. I know that in searching information out I have seen a lot more tweaks for these rather than the $E6 bin, my two PCM's came loaded with. The original PCM and a spare that I am "experimenting" with.

    Is this the reason for switching to $0D bins, being more hacks out there to compare data? Or better bin parameters, changes available? I have not looked at an $0D file yet.
    I wanted to try and keep my $E6 that I read out of my stock OEM pcm. As I have made no other trans gear changes or the like, Just the rebuild on the motor to a 383, and the use of a factory stock Camaro TPI intake setup. But if switching to the $0D is the way to go, I'll hunt one down.

    Thank you! I appreciate the help!

    Keith

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    Fuel Injected! bybyc5's Avatar
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    Quote Originally Posted by Six_Shooter View Post
    From what I understand all TBI systems (in the same ECM) have the same hardware resistance, and cyl number is set in the bin only.

    I do have a 3rd 16168625 PCM that came without a memcal/chip. So plugging in my memcal should give me another usable PCM to "play" with?

    When going to MPFI, there are different resistances based on cyl count, that set the injector firing scheme.

    Not sure I follow this (I am new to this kind of tuning, making one PCM work for different system than originally designed).
    Is this why the low impedance injector peak and hold resistors need to be bypassed for 8 high impedance saturated injectors?

    TBI fires twice as often as MPFI and this hardware change makes that work with MPFI. Anytime I've tried to run a TBI ECM on MPFI without a change a such would not run correctly.

    Does setting the Flag/Switch to "set" accomplish this? Or is the wire bypass needed still on the memcal?

    In reality the MPFI firing is 12345678. All injectors fire at the same time, at least when using ECMs original to MPFI. I haven't verified if this changes when using an MPFI converted PCM, such as the '7427 using $OD.
    So having Bank-1 and Bank-2 wiring really just splits the circuit load on the 2 injector drivers?

    Thank you for your help!
    I will get this figured out. I'm in for a penny in for a pound at this point!

    Thank you,
    Keith

  6. #6
    Super Moderator Six_Shooter's Avatar
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    In most non SFI OEM MPFI applications from GM, the ECM only had one injector driver. The only exception I can think of is the Turbo Sunbird, Turbo Grand Am, Sy/Ty and a Quad 4 application (Beretta?), that used the '7749, that has two injector drivers, but in saturated mode (Sy/Ty for sure), only one driver was used. in Peak and Hold mode (Sunbird and Grand Am), both injector drivers were used.
    The man who says something is impossible, is usually interrupted by the man doing it.

  7. #7
    Fuel Injected! bybyc5's Avatar
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    Quote Originally Posted by Six_Shooter View Post
    In most non SFI OEM MPFI applications from GM, the ECM only had one injector driver. The only exception I can think of is the Turbo Sunbird, Turbo Grand Am, Sy/Ty and a Quad 4 application (Beretta?), that used the '7749, that has two injector drivers, but in saturated mode (Sy/Ty for sure), only one driver was used. in Peak and Hold mode (Sunbird and Grand Am), both injector drivers were used.
    So inside the PCM there is only one driver for my 16168625 PCM. Then the control circuit for this driver must split inside and come out via two pins labeled "TBI A driver" coming out on pin A-16, and "TBI-B driver coming out on pin A-9. Or am I still lost?

    Must be for some kind of LHM, in the event of one injector failing?

    Thank you, I'm learning here!

    Keith

  8. #8
    Super Moderator Six_Shooter's Avatar
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    No, your PCM should have two injector drivers, what I was talking about was OEM MPFI applications, which your PCM was never used in.
    The man who says something is impossible, is usually interrupted by the man doing it.

  9. #9
    EFI GearHead ! EagleMark's Avatar
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    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.
    Attached Images Attached Images

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  10. #10
    EFI GearHead ! EagleMark's Avatar
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    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?

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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  11. #11
    Fuel Injected! JeepsAndGuns's Avatar
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    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.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  12. #12
    EFI GearHead ! EagleMark's Avatar
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    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...

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
    -= =-

  13. #13
    Fuel Injected! JeepsAndGuns's Avatar
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    And mine seems to run great with it, but I have never tried it without it. So it makes me really curious.
    79 Jeep Cherokee, AMC 401, T-18 manual trans, hydroboost, 16197427 MPFI system---the toy

    93 Jeep YJ Wrangler, 4.0L, 5 speed, 8.8 rear, homebrew hub conversion and big brakes, hydroboost, 2.5in OME lift, 31x10.50's---the daily driver

    99 Jeep WJ Grand Cherokee limited, 4.0L, auto, 2wd, leather and power everything, 99% stock---the long distance highway ride.

  14. #14
    Super Moderator Six_Shooter's Avatar
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    Quote Originally Posted by EagleMark View Post
    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.
    The man who says something is impossible, is usually interrupted by the man doing it.

  15. #15
    Fuel Injected! bybyc5's Avatar
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    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

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