TJ mack Posted August 15, 2022 Share Posted August 15, 2022 I have a mack E-7 350 that has no power on hills. Just seems to give up. I changed the crank sensor and the cam sensor. No change. I checked air the charge air side of things and all seemed fine. What’s your thoughts? Quote Link to comment Share on other sites More sharing options...
fjh Posted August 15, 2022 Share Posted August 15, 2022 (edited) Give us more info! Model of the truck and trans! Any fault light on? Changed fuel and air filters lately? Don't mean to be ignorant but you need to provide info to get info! Edited August 15, 2022 by fjh 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 15, 2022 Share Posted August 15, 2022 when was the last time you put new fuel filters on it?? Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 15, 2022 Author Share Posted August 15, 2022 Ive ran the truck over 250hrs like this. Ive changed fuel filters and I run the same fuel in everything I have. I have changed the air filter also. I looked all over for air leaks. Checked boots and clamps. No engine light on. It’s a dm 688 and it has an 8 ll. It’s all top end. I’m thinking about installing a boost garage next to see what’s up with that. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 15, 2022 Share Posted August 15, 2022 are you hearing a boost leak, excessive black smoke?? The combo you have should be a damn good truck. I assume a triaxle dump truck.. what do you haul? I also guess its an E-Tech.. '99 or newer? jojo 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 I’m not Harding a boost leak. No smoke and it is a triable dump. Normally around 73,000 pounds. It is an e tech engine Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 16, 2022 Share Posted August 16, 2022 Thats what I thought.. How long have you owned this truck, and what other trucks have you driven, that you are comparing this one too?? This truck should pull very well, but it aint no racecar... are you downshifting more than normal?? jojo Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 I’ve driven lots of regular Mack 300 and this truck on a hill will be just dead. Sometimes you can feel the power kick in and sometimes you don’t. It has no power band at all. I’ve had the truck almost a year. It’s been this way since i had it. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 16, 2022 Share Posted August 16, 2022 no throttle pedal codes?? boost sensor issue?? Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 No codes for them. Every now and then I will get one for the eup impulse. They will go off and if I clear them don’t come back for sometimes days. I Don’t know anything about them. Figured I would get a miss when bad. There not all the same cylinder also. Could it be them I need to change? Some have been changed for a miss fire. There not all the same year or time on them. On scan tool it shows throttle going to 100% so I didn’t think that was it. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 16, 2022 Share Posted August 16, 2022 dont jump into replacing EUP's.. remove the chrome heat shields, and see if the EUP wires are chaffed, and rubbing against the engine block.. the insulation does wear, and break off or rub off.. if the wires are exposed, you can use a brush-on wiring protector to cover the worn wire insulation. did you check the condition of the wires at the flywheel sensor? RPM/TDC sensor.. it is also very common that the wires on the engine side of the harness to be weak and even attached by only a few strands of wire. I have also found the pin in the plugs to be broken and barely touching.. since yours is a dump truck, there is a lot of sh!t coming off the left steer tire, and getting on to this wire harness.. Keep in touch...... jojo 1 Quote Link to comment Share on other sites More sharing options...
R.E.D Posted August 16, 2022 Share Posted August 16, 2022 Wouldn't hurt to check fuel pressure at the galley plug at the front of engine by Crank case filter. 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted August 16, 2022 Share Posted August 16, 2022 (edited) 😍 15 minutes ago, Joey Mack said: dont jump into replacing EUP's.. remove the chrome heat shields, and see if the EUP wires are chaffed, and rubbing against the engine block.. the insulation does wear, and break off or rub off.. if the wires are exposed, you can use a brush-on wiring protector to cover the worn wire insulation. did you check the condition of the wires at the flywheel sensor? RPM/TDC sensor.. it is also very common that the wires on the engine side of the harness to be weak and even attached by only a few strands of wire. I have also found the pin in the plugs to be broken and barely touching.. since yours is a dump truck, there is a lot of sh!t coming off the left steer tire, and getting on to this wire harness.. Keep in touch...... jojo Yup Also check Fuel pressure If you can ! R.E.D Great Minds! 😄 Tank Vent as well ! do All the cheap and easy stuff first changing EUPs is a last thing! Boost sensor Ambient air sensor if it has one! All cheap and easy stuff among all the stuff Joe has suggested! Another thought check the Engine ECU Plug wires for coolant push! Unclip them and look inside! Edited August 16, 2022 by fjh 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 Yes I will check this all out and report back. Thanks so much Quote Link to comment Share on other sites More sharing options...
Popular Post Mackpro Posted August 16, 2022 Popular Post Share Posted August 16, 2022 On the R /DM series cabs with the ETECH engines. The red engine shutdown light and the yellow electronic malfunction light are stand alone bulbs pushed in from the back of the dash onto the bulb holders . Problem with this style is the bulb falls out of the back or the bulb blows. Easy way to check is when you turn key on both lights should light up for a few seconds then go out. Many times I plugged the laptop in to find unknown active codes due to the lights not working. 2 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 Checked fuel pressure 60 to 70 psi checked boost pressure and max I could get was 21 ish psi 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 That’s on a gauge from the manifold 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 16, 2022 Share Posted August 16, 2022 did you use a gauge to check boost pressure?? or just a laptop? 21 seems low.. I would expect 28-31.. 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 That’s a mechanical gauge. 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 16, 2022 Author Share Posted August 16, 2022 Got a code for injector number #1 abnormal frequency pulse width, or period inactive 15 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 16, 2022 Share Posted August 16, 2022 OK... so I read this thread from the beginning.. Here I go... Do you have a Jacobs 690 engine brake or Powerleash? Next, Do you know how to run the valve's PROPERLY! on this engine? Including setting bridge lash? I'm talking 'By the book'.. not the 'Cat' way.. for example... jojo 1 1 Quote Link to comment Share on other sites More sharing options...
TJ mack Posted August 17, 2022 Author Share Posted August 17, 2022 It has a jacobs engine brake . I am a hood wrench but I’ve never done this anything under the valve cover. I would need an book. I was thinking about changing the number one eup. Quote Link to comment Share on other sites More sharing options...
fjh Posted August 17, 2022 Share Posted August 17, 2022 (edited) 1 hour ago, Joey Mack said: OK... so I read this thread from the beginning.. Here I go... Do you have a Jacobs 690 engine brake or Powerleash? Next, Do you know how to run the valve's PROPERLY! on this engine? Including setting bridge lash? I'm talking 'By the book'.. not the 'Cat' way.. for example... jojo I'm leaning to a fuel or programing issue how ever the above should defiantly be checked! What computer type stuff if any do you have access to read codes and look at parameters are you able to get too! (Interested in switch status for torque limit and min max governor settings!) EUP The code is maxed out May help to change it However ! you should install the Cal code if you change it and for that you need a computer if you have the computer hooked up you may just as well look at perimeters! Just sayin! Edited August 17, 2022 by fjh 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted August 17, 2022 Share Posted August 17, 2022 Yes Sir!!! 'F'... I leaned towards checking valve lash, just from a maintenance stand point. It's free to do, just some labor, and it is also a form of a 'health check'... Of course, he probably has ceramic lifters, so a PROPER valve adjustment is crucial.. 🤔 jojo 1 Quote Link to comment Share on other sites More sharing options...
Dirtymilkman Posted August 17, 2022 Share Posted August 17, 2022 Would there be a torque switch on the transmission on this one? 2 Quote Link to comment Share on other sites More sharing options...
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