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Holley MPI Injection??? Shawn are you there!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Donovan, Apr 2, 2001.

  1. Donovan

    Donovan 1/2 ton status

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    I have found a truck to replace my stolen blazer and the guy has the Holley MPI injection on it. It has a miss on when it comes off idle and up to about 2500rpms after that it runs real well. Has anybody had a chance to program these things yet? Is it that hard to do? Just want some idea what I am getting myself into.[​IMG] Also the computer looks like the 4Di computer but it is the MPI setup. Did they change computers? Sorry for all the none blazer questions.

    Donovan
    <A target="_blank" HREF=http://www.rustbucket.coloradok5.com>http://www.rustbucket.coloradok5.com</A>
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  2. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Sounds like the fuel map is off or the injectors are not sized correctly for the engine. It can be fixed, just need to spend some time with it. Once when you get it set correctly, you won't regret it. Holley did change computers to the new Commander 950 computer which does a few more things like timing control. There's nothing wrong with the 4di computer though. You might look on Holley's web sight for other base maps you can download or call their tech line and get some suggestions. Commander 950 and 4di base maps are not the same so make sure you get a 4di map. Down the road, you can go to the 950 Commander.

    Shawn
    87 K5
    few mods[​IMG]
    <A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
     
  3. Donovan

    Donovan 1/2 ton status

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    I am getting the truck this weekend and if I have any problems I might be calling on you.[​IMG] Yes I have been looking at the holley site and it looks like a sweet setup. The guy had it running pretty good. He also has a mallory ignition on it which will be coming off because I have never had good luck with them. He said he was getting 12 mpg empty with the new injection and with the carbuator he was getting 8 mpg. So I think I can get it to run a little better with time. Thanks will be talking I am sure.

    Donovan
    <A target="_blank" HREF=http://www.rustbucket.coloradok5.com>http://www.rustbucket.coloradok5.com</A>
    Bigger is Better
     
  4. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Yeah, get rid of the Mallory stuff for now and try to stay with things you know that works. Also be sure to get the 4di program disks, cable and the manual that comes with it. If he doesn't have that, I have both 4di disks and manual here you could copy. Not sure about SBC but my BBC, the large HEI distributer didn't fit that well between the MPI fuel rails. You will need a laptop and the special 4di cable to configure it. You can also use a desktop but it's a pain to use since you have to be outside of the vehicle to configure it. Go through all the sensors and the laptop should show a voltage/resistance readings of all sensors. Try to find the exact MPI kit he installed (350-450hp version). Thats what decide what injectors come with the kit.

    Shawn
    87 K5
    few mods[​IMG]
    <A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
     
  5. Donovan

    Donovan 1/2 ton status

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    I will make sure I get all that stuff. Did you get your beast running yet? That thing should run awesome. I was real impressed with the way the truck ran above 2500rpm. We will see.

    Donovan
    <A target="_blank" HREF=http://www.rustbucket.coloradok5.com>http://www.rustbucket.coloradok5.com</A>
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