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Thread: Tuning '94 chev Suburban Big Block

  1. #1
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    Tuning '94 chev Suburban Big Block

    In the process of tuning a 1994 Chevrolet Suburban with a Big Block. Found a 0E mask binary that works good with the 16197427 ECU. The binary file found is a BJKW 0E. The 454 big block was bored and stoked to 489 cu in. The cylinder heads were replaced with Edelbrock Oval Port heads. Also an Edelbrock TBI to batch MPFI conversion intake manifold was installed. The throttle body now has the upper fuel portion taken off and lower portion used as an air valve with TPS and IAC.

    Today adjusted the cylinder displacement and fuel flow constant upward by the percentage of change in displacement. Burned a BJKW+ file to chip and installed in ECU. Set the Autoprom APU1 in the vehicle and recorded the BLMs for on and off idle. The idle BLMs are right on the money at 128. The off-idle BLMs need some adjustment and not all that bad.

    Need help in identifying which parameter to use in the tables of the BJKW 0E mask binary. I have attached a jpeg file of what I believe are the applicable parameters. Would like confirmation from you folks that I am headed in the proper table items to modify the on and off-idle VE tables. Trying to locate and identify the two VE table to use to apply BLM spreadsheet corrections to. Also attached is the BJKW 0E binary file for inspection. Please advise. Thanks.
    Attached Files Attached Files

  2. #2
    Super Moderator dave w's Avatar
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    Open Throttle VE vs MAP vs RPM is for adjusting ~ Off Idle

    Idle VE vs MAP vs RPM is for adjusting ~ Near Idle

    It's a good plan to use closed loop data.

    dave w

  3. #3
    Fuel Injected! JeepsAndGuns's Avatar
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    Have you adjusted the injector offset Vs battery voltage? Since you have installed MPFI injectors, this needs to be changed to match the new injectors as it can have a big effect on how it runs. Are you using junkyard injectors or ones from a aftermarket company?
    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.

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    How is the idle quality with your setup ? I wasn't able to stabilize the idle and have it be respectable with my 502 setup until I went to PFI mode with the '7427. You didn't mention camshaft so that might be a difference.

    Your setup is very similar to mine before I went with the 502 , my original 454 was also bored and stroked to 489 , although it wore first a set of Vortec heads then a set of AFR heads and a few different cams .

    TOM
    1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
    2006 Forest river-Sierra 37' 5th wheel
    1999 Astro Van, L31 Vortec , 4x4 conversion
    1994 Pontiac Sunbird "Work ride"
    1993 K-3500 "Ex-diesel" 454/4L80E - '7427
    1992 454SS "Eh Stock" , Blower & '7427 swap .
    1992 S-10 434 SBC/Tremec - '7427
    1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
    1980 Z-28 454/700R4
    1977 Olds 98 Regency 403/700R4

  5. #5
    Fuel Injected! JeepsAndGuns's Avatar
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    Quote Originally Posted by Nasty-Z View Post
    How is the idle quality with your setup ? I wasn't able to stabilize the idle and have it be respectable with my 502 setup until I went to PFI mode with the '7427.
    I didnt even think about that. You did do all the required mods to run MPFI right?
    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.

  6. #6
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    Dave:

    Thanks again for the assistance. Don't understand the statement "It's a good plan to use closed loop data". Please expand on the statement please. Thanks.

  7. #7
    Super Moderator dave w's Avatar
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    Quote Originally Posted by rsicard View Post
    Dave:

    Thanks again for the assistance. Don't understand the statement "It's a good plan to use closed loop data". Please expand on the statement please. Thanks.
    Closed loop is when the computer takes full control of both fuel and spark based on the information from the sensors (Knock, TPS, O2, MAP, RPM, & CTS). Tune using only the data that was recorded when the computer was in closed loop.

    dave w

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    Tom:

    No problems with idle quality after installing Edelbrock TBI to batch injected MPFI via the 16197427 ECU. Did not know about the injector offset vs battery voltage. The conversion was done some 8 years ago. Purchased Craig Moates AutoProm APU1 which was of the initial production run. Talked to Craig and received some advice from him. Unaware about modifying the ECU and Edelbrock said nothing about it. Just did the conversion and it worked out. The Edelbrock kit (chose 502 cu in kit w/29 Lb/Hr injectors) came with new Intake Manifold, new Magnetti Marelli Pico Injectors, new fuel pump, and new programmed memory chip for ECU and other small hardware.

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    Quote Originally Posted by dave w View Post
    Closed loop is when the computer takes full control of both fuel and spark based on the information from the sensors (Knock, TPS, O2, MAP, RPM, & CTS). Tune using only the data that was recorded when the computer was in closed loop.

    dave w
    Dave: Did exactly that with a BJKW 0E altered binary and the Suburban is running fairly well. In the process of using your spreadsheet and BLM data to correct the BJKW binary. Looks to be a VERY good method/process. Again, thanks for all your assistance.

    Regards,

    Rolly
    Tucson, Arizona

  10. #10
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    Quote Originally Posted by JeepsAndGuns View Post
    I didnt even think about that. You did do all the required mods to run MPFI right?
    As I explained to TOM, the Edelbrock conversion was done some 8 years ago. Unaware of all this stuff when it was done. Worked fairly well. Used Moates APU1 to make changes about which I knew absolutely NOTHING! Still it worked out after capturing the Edelbrock binary supplied on their chip. Also purchased another programmed chip from which to extract data, although I had little idea about what I was doing. Still puzzled as to what the ECU mods really do. Still have not done them and yet the stock, with exception of the flash chip, ECU and Engine run just fine.

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    Gentlemen: Just to provide some background about myself, I really like working on Internal Combustion Engines especially the Small Block Chevrolet. It is a compact package capable of much horsepower depending on how much a person spends on building up one. I was in Aviation Electronics, known as Avionics, for 38+ years. Electronics is nothing new to me. Yet, getting through TunerPro RT V5.x is somewhat of a challenge. Have read many of the posts here on gearhead-efi. Am very greatfull for this Internet Site as it has been a wealth of knowledge. Many of you fellows have extensive knowledge just through exposure doing your own GM EFI projects. A special thanks to Dave W. as he had been VERY helpful. I have two chevrolet trucks that I work on. One a 1994 BBC Suburban and the other a 1995 Chevrolet C1500 2WD pickup that is in good condition except it leaks and uses engine oil. Am preparing a 350 Vortec and will be using a BBC TBI throttle body on top of a 4 barrel manifold with adapter. Just added a LT-4 Hot Cam to the Vortec and today the stronger Crane Cams valve springs came via UPS. Need to install these and mock up and set the fuel pressure regulator on the BBC throttle body. Then run the Vortec on my home brew run-in stand with a Holley 4 barrel carb. Also have a harness for the 16197427 ECU. Shall see if I can get the harness and BBC throttle body all mocked up on the run-in stand which provides NO dynamic load whatsoever to the Vortec. At least I can check for oil leaks etc. before installing same in the '95 pickup.

    It is nice to have you fellow to consult with.

    Regards,

    Rolly
    Tucson, Arizona

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    if you have a multiport intake and injectors I have no idea why you would want to run them in a tbi fueling mode. ya it'll run but leaves a lot on the table no?

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    Quote Originally Posted by tayto View Post
    if you have a multiport intake and injectors I have no idea why you would want to run them in a tbi fueling mode. ya it'll run but leaves a lot on the table no?
    The calibration from Edelbrock runs the 8 MPFI injectors in a batch fire mode , this setup is not a "true" MPFI setup but rather a small upgrade to get the fuel flow from the factory TBI out of the air stream and directly into the ports. The 16197427 will not support true MPFI.

    As I said in my earlier post , I tried to use the factory Edelbrock calibration on both my original 454 and the replacement 502 (509) in the '7427 , It ran OK , but I believe it left a lot on the table with the PCM in the original TBI mode. I switched to PFI mode in the PCM (Jumper mod only , no sense resistor mods) and it runs and idles much better.

    Just my experience , the OP states his idles just fine the way it is so he should be good to go.

    TOM
    Last edited by Nasty-Z; 01-22-2015 at 07:21 AM.
    1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
    2006 Forest river-Sierra 37' 5th wheel
    1999 Astro Van, L31 Vortec , 4x4 conversion
    1994 Pontiac Sunbird "Work ride"
    1993 K-3500 "Ex-diesel" 454/4L80E - '7427
    1992 454SS "Eh Stock" , Blower & '7427 swap .
    1992 S-10 434 SBC/Tremec - '7427
    1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
    1980 Z-28 454/700R4
    1977 Olds 98 Regency 403/700R4

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    Quote Originally Posted by Nasty-Z View Post
    The calibration from Edelbrock runs the 8 MPFI injectors in a batch fire mode , this setup is not a "true" MPFI setup but rather a small upgrade to get the fuel flow from the factory TBI out of the air stream and directly into the ports. The 16197427 will not support true MPFI.

    As I said in my earlier post , I tried to use the factory Edelbrock calibration on both my original 454 and the replacement 502 (509) in the '7427 , It ran OK , but I believe it left a lot on the table with the PCM in the original TBI mode. I switched to PFI mode in the PCM (Jumper mod only , no sense resistor mods) and it runs and idles much better.

    Just my experience , the OP states his idles just fine the way it is so he should be good to go.

    TOM
    By true MPFI, does that mean sequential MPFI versus batch MPFI? Still do not understand from an electronics standpoint why the resistors are removed and a jumpers installed.

  15. #15
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    Quote Originally Posted by rsicard View Post
    By true MPFI, does that mean sequential MPFI versus batch MPFI? Still do not understand from an electronics standpoint why the resistors are removed and a jumpers installed.
    By true MPFI I mean sequential , the '7427 will not support this . The normal "TBI" mode is injectors fire every 2nd DRP , the PFI mode I run the '7427 in is every 4th DRP (The '7427 can also run CPI mode which is every DRP). What I experienced in running the PCM in TBI mode with the 8 injectors is that the PW went so low idle quality started to be affected.

    I do not know the whole story behind the sense resistor bypass , I was told for the conversion to be 100% reliable it needed to be done , I have over 75K and 10+ years on my conversion on only the Netres mod .

    TOM
    1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
    2006 Forest river-Sierra 37' 5th wheel
    1999 Astro Van, L31 Vortec , 4x4 conversion
    1994 Pontiac Sunbird "Work ride"
    1993 K-3500 "Ex-diesel" 454/4L80E - '7427
    1992 454SS "Eh Stock" , Blower & '7427 swap .
    1992 S-10 434 SBC/Tremec - '7427
    1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
    1980 Z-28 454/700R4
    1977 Olds 98 Regency 403/700R4

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