OJ Avery Posted April 18, 2019 Share Posted April 18, 2019 Hey! I was wondering how common a problem is injector leak down causing no start over night on a MP7? I've had it happen 2 times now and the first time I understand. It had OE injectors, ran really good n o codes. Cylinder balance was off a good amount (I don't recall how much) . I replaced the fuel filter head....which did have a sticking check valve. Same problem. We replace a lot of injectors here because of how the equipment is used. So I did the injectors in that one, problem solved. This one I just did is a MP7 also. It had injectors 18 months ago (conical). No start overnight, have to prime it to start it. Cylinder balance was off especially for recent injectors. The difference on the cylinder balance between 5 & 6 was 50. It also showed air in fuel. We went over all fuel lines and connections and all looked good. I finished the injectors and ran it. Shut it off at 2 yesterday and it fired no problem just now. Quote Link to comment https://www.bigmacktrucks.com/topic/56779-question-for-the-mack-techs/ Share on other sites More sharing options...
fjh Posted April 18, 2019 Share Posted April 18, 2019 Take note if this happens after a hard days work! if so you may have a injector cup issue!Is fine to replace injectors however if the cups are pitted you are wasting injectors they need to mate properly! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/56779-question-for-the-mack-techs/#findComment-420826 Share on other sites More sharing options...
OJ Avery Posted April 18, 2019 Author Share Posted April 18, 2019 I always replace the cups with injectors, I don't like doing the job twice Quote Link to comment https://www.bigmacktrucks.com/topic/56779-question-for-the-mack-techs/#findComment-420832 Share on other sites More sharing options...
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