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6.9 cranking but no start

Discussion in '6.9L IH & 7.3L IDI Diesels' started by dreed86, Dec 31, 2020.

  1. hacked89

    hacked89 Full Access Member

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    Some FYI's - harbor freight was the only place that had it that cheap around me. If you go with it, I have a video on YouTube if you Google 7.3 idi compression test harbor freight on how to modify it to go through the glow plugs.

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  2. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    It depends on the type of starter. If it was a Mitsubishi, then no it wasn't that bad. If it was a Nippendenso, then it was bad. I looked at it and thought that it's a Mitsubishi starter, but can't remember for sure. I'm doubting myself at this point. While glow plugs do cost more than a compression tester, they are almost needed to drive the truck while a compression tester isn't. Of course if the engine doesn't at least attempt to fire after using the block heater, then a compression tester would be a good investment.
    Since the truck's been sitting for a couple of years (maybe longer) the compression will probably read lower than it would after being run and completely warmed up. If the readings seem low, don't immediately assume that it's bad.
     
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  3. hacked89

    hacked89 Full Access Member

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    The warm compression test on an IDI takes the place of a traditional wet test. If the cold is out of wack something is still wrong.


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    Last edited: Jan 13, 2021
  4. Team Dirt

    Team Dirt Registered User

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    My truck was running rough then quit altogether. Pulled the pump and sent it to Thompson valley diesel injection in scotch creek BC. for 900$ they rebuilt the pump. Put it back on truck and it ran like a brand new truck. All of a sudden one day it started missing and smoking again. Bought a compression tester and cold test had 225psi give or take a few pounds on all holes except 4 and 6. Those holes had zero. Failed head gasket between those holes. Tester I bought had glow plug and injector fitting. Pulled the injectors and took them to the same shop that did my pump where they pop tested them for free and they all tested good. I guess the head gaskets are trouble on these engines. The compression tester was a huge asset to help diagnose. This spring I will pull the engine and do the heads and gaskets and maybe farther if I have the cash. This is on an 83 also. Hope you get your issue figured out.
     

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