JoeH Posted August 12, 2023 Share Posted August 12, 2023 My E7-350 peaks at 35 psi boost. If think a 400 would do at least that. Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536837 Share on other sites More sharing options...
Anonymous Posted August 12, 2023 Author Share Posted August 12, 2023 3 hours ago, fjh said: So try turning the screw in on the fac under the little cap that screw determines where the fuel starts coming on it! Turn it in half to one turn and try it! Max 20 pounds boost is off by at least 8 psi you should be making 28 to 30 ! Are you talking about the star wheel or what some people call the “smoke screw” on the backside? I have the star wheel set pretty lightly but the I found the smoke screw was backed all the way out. I turned it in and started driving and adjusting until I ran out of time l. Seemed to have a little improvement. Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536840 Share on other sites More sharing options...
fjh Posted August 12, 2023 Share Posted August 12, 2023 2 hours ago, Anonymous said: Are you talking about the star wheel or what some people call the “smoke screw” on the backside? I have the star wheel set pretty lightly but the I found the smoke screw was backed all the way out. I turned it in and started driving and adjusting until I ran out of time l. Seemed to have a little improvement. The little two screw cap on the back ! That determines where fuel starts coming on related to boost! It won’t likely give you the boost you’re after but will improve gidy up go ! Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536844 Share on other sites More sharing options...
Anonymous Posted August 13, 2023 Author Share Posted August 13, 2023 Had some time to tinker today. Here's what all I did. Loosened the afc all the way up. No difference. Tightened the "smoke screw" all the way in to push the afc to wide open and kinda bypass the afc was my thinking. No difference. Even pulled the pipe off the muffler elbow to make sure it wasn't plugged up somehow. No difference. Double checked the turbo for shaft play and to see if it had any oil in it only to find it clean and free of play. Guess I will make sure the timing is correct and if so I believe I need to send the pump back off and have it rechecked. Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536895 Share on other sites More sharing options...
fjh Posted August 14, 2023 Share Posted August 14, 2023 5 hours ago, Anonymous said: Had some time to tinker today. Here's what all I did. Loosened the afc all the way up. No difference. Tightened the "smoke screw" all the way in to push the afc to wide open and kinda bypass the afc was my thinking. No difference. Even pulled the pipe off the muffler elbow to make sure it wasn't plugged up somehow. No difference. Double checked the turbo for shaft play and to see if it had any oil in it only to find it clean and free of play. Guess I will make sure the timing is correct and if so I believe I need to send the pump back off and have it rechecked. Sounds like the only plan now you done all you can do! Timing will not give you what you’re missing there! Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536904 Share on other sites More sharing options...
Anonymous Posted August 15, 2023 Author Share Posted August 15, 2023 Well curiosity got the best of me this morning. I decided to take one more look at the turbo before I send the pump off. I removed it this time and really wanted to get a better look at the exhaust side. At first glance everything looked fine. But as I was on a phone call I was fidgeting spinning the compressor side when I noticed it had a drag for a split second then it released and spun freely. Kept on messing with it and it kept doing the same thing. I put some shop air to the exhaust side and it didn’t spin as free as it should. Would come to a stop as if it had a break applied to it. Then I removed the exhaust housing and found the carnage. New turbo should be here later this week. 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536982 Share on other sites More sharing options...
JoeH Posted August 15, 2023 Share Posted August 15, 2023 (edited) Sounds like curiosity saved the dog... Great find! Makes sense that a blown engine ate the turbo. We should have picked up on that tidbit and thought it through a bit better. Edited August 15, 2023 by JoeH 1 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536987 Share on other sites More sharing options...
fjh Posted August 15, 2023 Share Posted August 15, 2023 Yup agree ! I’m surprised it wasn’t smoking more! I at one point was going to suggest looking at the turbo however you said there was no smoke under load!sounded like lack of fuel! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536989 Share on other sites More sharing options...
Anonymous Posted August 15, 2023 Author Share Posted August 15, 2023 I feel like an idiot for it catching it earlier. And I also thought it should be smoking more. Guess it was getting just enough air to keep smoke down. Now I have to try and get the pump set back to where it was when I started. Will give a full report all is done. Thanks for all the help. Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536993 Share on other sites More sharing options...
fjh Posted August 15, 2023 Share Posted August 15, 2023 13 hours ago, Anonymous said: I feel like an idiot for it catching it earlier. And I also thought it should be smoking more. Guess it was getting just enough air to keep smoke down. Now I have to try and get the pump set back to where it was when I started. Will give a full report all is done. Thanks for all the help. Naw just hold off till you get the turbo and see how it is ! Back the smoke screw out to its aprox location and tweak it so you got just a whisper of gray! And if you’re achieving about 28 to 30 psi boost your right as rain!😀Nice thing is you covered all the other bases!All good! Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-536998 Share on other sites More sharing options...
Joey Mack Posted August 15, 2023 Share Posted August 15, 2023 Heck, dont feel bad.. when we work on so many things at one time, it is possible to miss something basic.. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-537001 Share on other sites More sharing options...
fjh Posted August 15, 2023 Share Posted August 15, 2023 We once had a truck that worked well for 6 months then wouldn’t pull still under warranty! We checked everything except the turbo! They wouldn’t let us change the turbo it was a vmac engine!after all the checks were done other than the turbo They put a top secret program in this truck and it layed down black smoke like no buddies business! Still didn’t pull ! They finally gave in and put him in a new truck! That said we all thought and still think a turbo would have cured the truck however water under the bridge! Would really like to know if the turbo would have cured this we never heard ! The truck was sold to a different person that didn’t know any better! All the evidence pointed to lack of air but know one would listen! Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-537015 Share on other sites More sharing options...
Anonymous Posted August 18, 2023 Author Share Posted August 18, 2023 What a difference a new turbo makes. Got 25psi boost just driving not hooked to anything. Going to tweak the pump a little and try and get a little more out of it. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-537229 Share on other sites More sharing options...
fjh Posted August 18, 2023 Share Posted August 18, 2023 11 hours ago, Anonymous said: What a difference a new turbo makes. Got 25psi boost just driving not hooked to anything. Going to tweak the pump a little and try and get a little more out of it. pull some thing before you get carried away ! if you can get 28 to 32 is good numbers for a 400 ! A 454 will make 35 -37 . if you don't got a pyro get one! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-537279 Share on other sites More sharing options...
doubleclutchinweasel Posted August 18, 2023 Share Posted August 18, 2023 A good hair dryer definitely helps. Quote "Eagles may soar, but weasels don't get sucked into jet engines." Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-537309 Share on other sites More sharing options...
Anonymous Posted September 24, 2023 Author Share Posted September 24, 2023 Back at it!! So after some use with the new turbo I still fell like I'm short on power. For reference I hooked my lowboy to a friends freight liner with a wore out M11 in it and it ran much better than my truck. I have decided to send the pump back to the pump shop. So I pulled it off this morning and noticed the rack plug is stamped 2000. And from my younger days we used to take the "Mack rack plug" stamped 2095 and put them in our dodges so the pumps would go full rack. My question is did Mack use any other rack plugs other than the 2095 plug? I did talk to the previous owner of the truck and he had the pump rebuilt at some point and said it never ran as good as it did before they had it rebuilt. Im wondering if someone put the wrong plug back in the pump. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/73117-e7-400-low-power/page/2/#findComment-539205 Share on other sites More sharing options...
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