Testing the IP

Discussion in '1982-Present GM Diesel' started by 6.2puller, Nov 20, 2005.

  1. 6.2puller

    6.2puller 1/2 ton status

    Jul 8, 2004
    Likes Received:
    New England
    Any way to test the injection pump? My brother was given a 84? GMC 3500 with 6.2l today. It has not been run in over a year. We unpluged the IP and cracked an injector as well as the fuel line going into the IP. We got fuel at the IP then hooked that back up. Turned her over and got fuel to spirt out the injector for a second then nothing. We have cranked it over for a while with no results. Amazingly the starter and cables are taking this way better than I thought they would.
    So any way to test the IP is running? It sounds like it is doing something.
  2. diesel4me

    diesel4me 1 ton status Premium Member

    Jul 24, 2003
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    When I woke my diesel after sitting a long time,it was a bitch to get it fired up the first time..I used a gallon jug for a temporary "fuel tank",and put the fuel line and return line in it..had to loosen ALL the injector lines,just cracking a few didn't do it!..cranked it until the batteries died twice,before I finally got it to start.. :doah:

    I eventually found dry rotted fuel lines were letting air seep in,after I finally got it to start with ether,as much as I hated to use any..after I fixed the lines and got it running that first time,it has always started good so far..

    I added an electric fuel pump right after the gas tank,and a set of manually controlled AC G60 glowplugs..had to swap in a rebuilt starter drive bendix--it got wounded from using starting fluid..disable the glow plugs if you feel you must use starting fluid,by pulling the 2 prong plug off the top of the glow plug relay on the drivers side inner fender..its really bad for a 6.2,they don't like ether--it can shatter pistons and hurt other things too...I used it as a last resort..some say WD-40 works too,and isn't as potentially harmful..

    If you got fuel at the injector pump coming in,then the lift pump must be working(fancy diesel name for a fuel pump--its on the block just like a 350)..be sure the filters aren't clogged..if you got fuel at one injector,even just a sqirt,the pump is probably ok,just still airbound..

    Dont crank it too long without letting the starter cool down awhile..they are not cheap--it cost me 38 bucks just for a REBUILT starter drive--a new one is 75 bucks..whole starter was 150 at the cheapest parts store..

    Rule #1 on a diesel..NEVER LET IT RUN OUT OF FUEL!!.. :doah: ...especially a GM diesel,that has no "priming pump" to get the air out easier.. :( I think the addition of the electric pump helped my truck start much quicker,like it primes the injector pump some.. :crazy: ..Good luck!

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