robp823 Posted January 15, 2014 Share Posted January 15, 2014 We have a c15 acert mxs 625 hp.Its only making 40 psi of boost loaded.pressure tested CAC and all intake piping.Checked all connections from turbo to turbo.Used a air pressure regulator to test wastegate.On the wastegate it's stamped 25.86 psi.When I'm adjusting the regulator and hit 25 psi the wastegate starts to open and at 40 psi wastegate is fully open.Looked up the test spec on SIS.Shows spec of 51 psi of boost.Everyone else I have talked including some of the drivers say that it should make 60 psi.What am I missing here? Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 16, 2014 Share Posted January 16, 2014 Verified boost with known good manual gauge? What chassis? Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 16, 2014 Author Share Posted January 16, 2014 not yet will verify tonight.Its in a kenworth W9.Also inspected turbos for damage or excessive bearing play.There fine. Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 16, 2014 Share Posted January 16, 2014 What's the complaint? Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 16, 2014 Author Share Posted January 16, 2014 Runs like dog.Low boost. Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 16, 2014 Author Share Posted January 16, 2014 Fuel pressure in spec as well. Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 17, 2014 Share Posted January 17, 2014 So no power? Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 17, 2014 Author Share Posted January 17, 2014 Correct Quote Link to comment Share on other sites More sharing options...
ktmlew Posted January 18, 2014 Share Posted January 18, 2014 Did you check the glow plug gap? Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 18, 2014 Share Posted January 18, 2014 How is the top set? Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 18, 2014 Author Share Posted January 18, 2014 Tight Quote Link to comment Share on other sites More sharing options...
Jeff Clyde Posted January 18, 2014 Share Posted January 18, 2014 worn or out of adjustment clutch ? Different truck/ engine, but had one that had a whole wack of work done to fix low power, but the cause was a slipping clutch Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 20, 2014 Author Share Posted January 20, 2014 hmmmmmm ill check that. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 23, 2014 Share Posted January 23, 2014 How many miles are on this engine/ injectors? what is your intake restriction at as well as exhaust restriction. How are you loading the engine down, test drive with heavy trailer or dyno? Has it had any recent work done to it( injector replacement, overhead set, etc.) Sorry for all questions and no answers Quote Link to comment Share on other sites More sharing options...
Aaron Posted January 23, 2014 Share Posted January 23, 2014 I asked about the top set earlier. He said tight. But I'm not sure if that's tight as in not enough lash or it's ok. Quote Link to comment Share on other sites More sharing options...
robp823 Posted January 24, 2014 Author Share Posted January 24, 2014 The engine just had an in frame with new injectors about 15,000 miles ago.Checked overhead and when I said tight I meant it was in spec but on the tighter side.We are testing the truck with a loaded trailer.Did not perform intake or exhaust restriction tests. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted January 29, 2014 Share Posted January 29, 2014 Did the low power condition begin with the overhaul? Have the parts installed during the overhaul been verified to be correct, I have on 2 occasions found the wrong parts installed during major engine repairs. I really wish trucks did not have boost gauges. Most drivers dont really understand what boost is or how it is produced. Most see the guage didnt go to 40 this time only 37 so there must be low power. Been on many a wild goose chase because of this. Anyway, another thing to consider is the load or route this truck is taking, has it changed when the power complaint started? Quote Link to comment Share on other sites More sharing options...
robp823 Posted February 1, 2014 Author Share Posted February 1, 2014 They did a platinum kit.As far as I know all the parts are correct and the injectors were programmed.I was curious to that myself because I recently found out that the turbos are different on higher horsepower models.The truck does have the correct turbo installed. Quote Link to comment Share on other sites More sharing options...
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