Reid Posted June 9, 2022 Share Posted June 9, 2022 HELP!! I have a 2009 MACK MRU613 Front load refuse truck. this truck will not get above 55mph. we have replaced the turbo and actuator. the boost sensor, the fuel pressure sensor. the fuel pump has also been changed. the truck shows no codes at all. nor the transmission, not one single code. We had the DPF system deleted, and the truck still will not get up to speed. the truck struggles most going up hills, and out of first gear. ANY AND ALL COMMENTS ARE HELPFUL! Quote Link to comment https://www.bigmacktrucks.com/topic/69928-truck-derate-and-egr-delete/ Share on other sites More sharing options...
Mackpro Posted June 10, 2022 Share Posted June 10, 2022 Did you have this issue before the Delete? Did this truck have DEF fluid/SCR system on it? The combustion valve on the intake manifold could be stuck open or leaking abs sending boost pressure into the bottom of the DPf housing. Fuel pressure needs to be around 55 idle and 65 at 1200 rpm. Boost pressure should be hitting 31-32 psi under a load . Turbo wheel speed should be hitting 109,000 RPM,. Any boost pressure leaks can kill a MP7. Boost pressure sensors are different between SCR engines and non SCR engines. Wrong one can cause low power. Any major tire size changes? Going from 22.5 LoPro to 24.5 full size with out changing the revs per miles can really mess one up. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/69928-truck-derate-and-egr-delete/#findComment-499796 Share on other sites More sharing options...
fjh Posted June 10, 2022 Share Posted June 10, 2022 Yup you have posted this in the right spot for replies ! So most people here are former or current Employees or owners ! Most guys don't like dealing with deletes as there are so many variables Mac pro is one of several guys here still current and may be able to assist ! I Am Not and have never been A MP engine fan So my Advice is only Observation and hearsay ! So listen up to what he has to say! Others may chine in They may try to help How ever Deleted engines make it hard to work with ! I do have one suggestion and that would be unplug the EGR Valve and see if this changes your situation It will throw a code But if the power gets worse or better it may give you a direction to go! Quote Link to comment https://www.bigmacktrucks.com/topic/69928-truck-derate-and-egr-delete/#findComment-499841 Share on other sites More sharing options...
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