am3101 Posted February 12, 2009 Share Posted February 12, 2009 our mack CHR select 1994 looses power in the higher gears.we changed the filters and drained the oil.at the moment we are getting the injector checked out,but so far they dont know either.any suggestions and ideas greatly appreciated!tony Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/ Share on other sites More sharing options...
Maxville Truck Posted February 13, 2009 Share Posted February 13, 2009 CHR? Which engine?WE had an older e-6 350 in a 1990 R model mack that we had turned the pump up on, under full load for an extended period of time (15 or more seconds). the truck would flutter and fall on its face....Obviously we tried the filters, no luck checked for bad lines from the tank (ones letting air in) nothing appeared bad...One of the fuel lines had collapsed internally......... we found it after we started replacing all the fuel lines (it was a short one near the fuel pump that had a pretty severe bend in it (4th one we checked though)Other wise as I stated earlier check for interjection of air someplace (loose fuel line fitting or bad line).Good Luck Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30692 Share on other sites More sharing options...
fjh Posted February 13, 2009 Share Posted February 13, 2009 I would head in the direction you have been pointed, T in a fuel preasure gauge at the fuel pump and check preasure there full load it should not drop below 20 psi full load .If it does check all the lines and if they are clear check to see the drain back valve spring is not broken,I'm kinda working blind here and am assuming its not e7 or vmack. transplant. Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30723 Share on other sites More sharing options...
Mackpro Posted February 13, 2009 Share Posted February 13, 2009 our mack CHR select 1994 looses power in the higher gears.we changed the filters and drained the oil.at the moment we are getting the injector checked out,but so far they dont know either.any suggestions and ideas greatly appreciated!tony I assume this CHR has a Cummins and your outside of the USA? I would like to see pics of your CHR and how they put the Cummins in there. Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30725 Share on other sites More sharing options...
fjh Posted February 14, 2009 Share Posted February 14, 2009 I assume this CHR has a Cummins and your outside of the USA? I would like to see pics of your CHR and how they put the Cummins in there.Good catch Bro! Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30769 Share on other sites More sharing options...
am3101 Posted February 14, 2009 Author Share Posted February 14, 2009 it's a E7 engine VMack.horsepower 427.it's not the injector pump,thats been checked.its not fuel lines,been checked too.the mack computer doesnt show up any faults.we keep looking,thanks for the responses so far..tony Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30833 Share on other sites More sharing options...
fjh Posted February 15, 2009 Share Posted February 15, 2009 Good catch Bro!Ok check the fuel preasure 20 psi or more the betterWhat trans do you have if the engine is only making 15 or so psi boost check the torque limit switch on the trans unplug it if its hooked up see if that helps! Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30835 Share on other sites More sharing options...
am3101 Posted February 15, 2009 Author Share Posted February 15, 2009 (edited) Ok check the fuel preasure 20 psi or more the betterWhat trans do you have if the engine is only making 15 or so psi boost check the torque limit switch on the trans unplug it if its hooked up see if that helps!psi is alright.its a 10 speed rockwell road ranger.already tried unplugging by now as well.its a mack engine too and not a cummins.. Edited February 15, 2009 by am3101 Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30842 Share on other sites More sharing options...
fjh Posted February 15, 2009 Share Posted February 15, 2009 psi is alright.its a 10 speed rockwell road ranger.already tried unplugging by now as well.its a mack engine too and not a cummins..what kind of boost is it making? Does it smoke black under load?Does the pyro read high 900 + Quote Link to comment https://www.bigmacktrucks.com/topic/8309-loss-of-power-in-higher-gears/#findComment-30854 Share on other sites More sharing options...
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