Dan107 Posted March 24, 2018 Share Posted March 24, 2018 So after a $20K bull gear replacement expense I now have an issue with power. I'm leaning toward an injector and cup problem, but I'm not sure. The truck is a 2012 Mack Pinnacle MP8 with 560K miles. I have to hand prime the truck every morning to avoid the long cranking start times. Once it is started, it runs well at idle, but between 12 and 1400 rpm it feels like the truck is running over rumble strips and looses power. Once it's past 1400 RPM it smooths out and all is good. I pull 84K pound loads if that helps. I also get a "check fuel filter" warning on the display at times. It has also said there was a fuel restriction. I have gone through three different sets of fuel filters, finally purchasing Mack filters trying to fix this. I'm not sure where to look next, but from reading the posts here am leaning toward possible injector cup and injector issues. Might this be correct, or is there something I'm missing? Any help is greatly appreciated. Quote Link to comment https://www.bigmacktrucks.com/topic/52905-and-now-this/ Share on other sites More sharing options...
Dirtymilkman Posted March 25, 2018 Share Posted March 25, 2018 Definitely injection cups and a slight possibility of filter housing leaking. Quote Link to comment https://www.bigmacktrucks.com/topic/52905-and-now-this/#findComment-395051 Share on other sites More sharing options...
Dan107 Posted March 25, 2018 Author Share Posted March 25, 2018 Thank you for the reply and the assistance. Quote Link to comment https://www.bigmacktrucks.com/topic/52905-and-now-this/#findComment-395092 Share on other sites More sharing options...
fjh Posted March 25, 2018 Share Posted March 25, 2018 Make sure your primer pump is locked down! Quote Link to comment https://www.bigmacktrucks.com/topic/52905-and-now-this/#findComment-395100 Share on other sites More sharing options...
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