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ECM tricks

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by edeslaur, Nov 19, 2000.

  1. edeslaur

    edeslaur Registered Member

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    Hi all,

    I recently transplanted a healthy roller cam 88 Police 350 into my my 88 K5 Blazer. Unfortunately, the cam is bigger than the EFI likes, so I've been trying to build the ALDL interface at http://www.techedge.com.au/vehicle/aldl/160/aldl_hw.htm. OK, it's built, but doesn't seem to work. One misinfo item is that it seems 12 V is from pin C rather than H (my H is blank and the wiring diagram supports this).

    Anyone have any other solutions (other than buying a scanner - the point here is to be learning something I don't know as I do this) for pulling engine info?

    I have the codes (lean) and just need the rest of the info so I can start working out the changes to the factory ECM to get this to work better.

    The engine is quite healthy (not as good as when it had a carb, but not bad) until it shifts to open loop mode, then it runs about as well as stock did until it gets warm enough to ping (under > 1/2 throttle accel), then timing is retarded and it runs less well until a shutdown/restart is effected (hey, is my ECM running Windows?). LOL

    TIA,
    Eric D.
     
  2. K5 NUTT

    K5 NUTT 1/2 ton status

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    ooh...something i like to tinker with. I do alot of electronic work at the shop (Freightliner)...granted...Cat Detroit and Cummins are a whole lot different than chevy but they have alot of similarities...especially the Detroit which actually used the same aldl port that gm used till the advent of OBD2....course the advent of DDEC3 saw the aldl get replaced with a 6 pin deutch. Anyways you can short the A and D pins to pull codes...but to access and watch the data stream for important info such as block learn you will need a scanner...i have a MPSI Pro_link 9000...my software stops at 93 but the K5 stopped at 91 so its not an issue for me. If the cam is to healthy you will need to make a new chip so the puter has a new fuel map to pull data from to run right...however emissions can come into play at this time...if it is way healthy a set of big block injectors might help you out also with an adjustable fuel psi regulator. Since i'm carrrying on i'll stop right now...hope i answered your question....gonna go check out that url.

    AZBLAZER

    1979 K5
    1976 K5 Chalet
    1972 K10 Suburban
     
  3. edeslaur

    edeslaur Registered Member

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    If you like that, check out this one: http://www.diy-efi.org/gmecm/
    Everything you EVER wanted to know, including dual TBI setups for your SB.
     
  4. K5 NUTT

    K5 NUTT 1/2 ton status

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    Bud...i loved that site...gonna build that unit. Here is the low down....Baud rate = how many bits/bites a puter can send and recieve info in a given time frame....cureently the semi's are running the J1587...and gearing up for the transition to the J1939...still slower than cars but getting there. Anyways what they show you how to build for a nice dinner at a resturant costs around $400 bones in my buisness...MPSI makes one we use and its called the MagicKey....Cat has there own box and so does Cummins....at a great expense...with this info i could finger out the mystery inside the box and with a little help from a friend we might be able to build our own ECM to Puter interface box...and save a ton of dough!!! Will check that other site right now!~!

    AZBLAZER

    1979 K5
    1976 K5 Chalet
    1972 K10 Suburban
     
  5. edeslaur

    edeslaur Registered Member

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    Where in AZ are you (AZBlazer)? I lived in Sahuarita, south of Tucson for a while. I used to play programmer during the day (manager, ugh, now), just always been hardware stupid.

    There are several other solutions as well. If you look on the GMECM site, one guy built a unit with an LCD display, no computer necesary.

    Then there's tunercat and a ton of other sites.

    I'm having fun, but wish I was more hardware literate. At least I know what the heck a transistor really is & what it does after building that interface.

    Maybe you know - is there a functional difference between an NPN and a PNP transistor? I used a 2N2907A rather than a 2N2907, but was told they are compatible & found a website that agreed.

    Eric D
    88 K30 Blazer
     
  6. K5 NUTT

    K5 NUTT 1/2 ton status

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    My buddy at the shop is top dog in the shop...he is going to school for Electrical Enginering....my job is trying to keep up with all the changes on a wide vaiety of sytems...eaton vorad...abs (rockwell-eaton-bosch)..automated trans issues.....hard to do but i am pretty good at finding the problems...then i repair the wiring and or replace the component. Matt can actually build the neat stuff on the site...matter of fact i am calling him asap in the am so he can check out these web sites. Gonna give it up now though...was only gonna check email really quick and the forum...its now allmost 2 am....lol. And i could go on for hours more...hehehe....specially that darn site with the actual stuff to burn memcals...lol.

    I live in glendale...a suburb of phoenix....43rd ave and glendale. I work at I-10 and 99th ave.

    AZBLAZER

    1979 K5
    1976 K5 Chalet
    1972 K10 Suburban
     

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