GOOG Posted March 4, 2020 Share Posted March 4, 2020 I just bought a 2003 RD688SX tandem dump truck. It has a 8LL and 400. I really like the truck. It pulls well but has a two second lag between when you lay the fuel to her and when she starts to hunker down and pull. I intend to put a bigger turbo and honed out injectors on it, but am concerned that this lag will still haunt me. Have anyone been down this road? Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/ Share on other sites More sharing options...
brettj3876 Posted March 5, 2020 Share Posted March 5, 2020 Electronics. It's working how it's supposed to, not giving it all the fuel before she spools up Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444456 Share on other sites More sharing options...
fjh Posted March 5, 2020 Share Posted March 5, 2020 (edited) Yup It is what it is! Also in that model year if the ecu Sees any more than 33 psi boost it will derate you So trying to get any more out of it is quite difficult! That is a good find thou ! RD SX One tough truck Edited March 5, 2020 by fjh Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444487 Share on other sites More sharing options...
Mack Technician Posted March 5, 2020 Share Posted March 5, 2020 (edited) Does the valve cover tag say AI400 for HP? That would explain some of the issues. Edited March 5, 2020 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444540 Share on other sites More sharing options...
david wild Posted March 6, 2020 Share Posted March 6, 2020 Bet it is a AI and that is the problem but hopefully Mack tech can set you on the road to redemption. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444565 Share on other sites More sharing options...
Mack Technician Posted March 6, 2020 Share Posted March 6, 2020 (edited) 9 hours ago, david wild said: Bet it is a AI and that is the problem but hopefully Mack tech can set you on the road to redemption. Redeeming a prostitute back to a lady of good reputation is only a turbo and 6 injectors away. You ever see your old AI460 RD out and about....or what they did with it? Edited March 6, 2020 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444583 Share on other sites More sharing options...
fjh Posted March 6, 2020 Share Posted March 6, 2020 12 hours ago, david wild said: Bet it is a AI and that is the problem but hopefully Mack tech can set you on the road to redemption. Don't ever recall seeing an AI engine in an RD ! However don't mean it ain't so ! The first AI engines appeared on the seen here in the CV models! And the first real issues we had with them was the fan hub bearings failing in short order And Having a huge back log on hubs ended up having to buy bearings and rebuilding the hubs as a get by till the hubs were available for warranty purposes! Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444594 Share on other sites More sharing options...
GOOG Posted March 6, 2020 Author Share Posted March 6, 2020 What does AI mean? I'll look at the valve cover tomorrow. My concern is if I put Rochester injectors and turbo on it, will the lag go away? I have their stuff on another truck and love it. Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444614 Share on other sites More sharing options...
Mack Technician Posted March 7, 2020 Share Posted March 7, 2020 (edited) 22 hours ago, GOOG said: What does AI mean? I'll look at the valve cover tomorrow. My concern is if I put Rochester injectors and turbo on it, will the lag go away? I have their stuff on another truck and love it. Non-cooled Internal EGR. Figure out the issue first or you’ll be feeding penicillin to a cancer victim. Your problem could be software.....if it’s AI. Edited March 7, 2020 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444684 Share on other sites More sharing options...
GOOG Posted March 8, 2020 Author Share Posted March 8, 2020 There's nothing on valve cover. Where else can I get the info you need? Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444705 Share on other sites More sharing options...
Mack Technician Posted March 8, 2020 Share Posted March 8, 2020 Click on the above link and use the pics on the first page to visually match which manifold you have on your engine. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-444716 Share on other sites More sharing options...
david wild Posted March 11, 2020 Share Posted March 11, 2020 NO AI in RD ???? sold mine to Mark Kamp so there was plenty of them around. Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-445004 Share on other sites More sharing options...
Mack Technician Posted March 11, 2020 Share Posted March 11, 2020 (edited) I haven’t seen many in an RD or DM either. They’re out there. Think the CV was attractive and took over on the vocationals during the AI generation. Edited March 11, 2020 by Mack Technician Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-445015 Share on other sites More sharing options...
ALLSTATE Posted October 3, 2021 Share Posted October 3, 2021 I have a 2003 cv713 granite with 120k original miles. I only had this truck for a month and I can’t stand how bad the low end power is. I just installed a module from ag solutions and it helped with mid range power and top end. Fully loaded 78k it will run 75 up amd down hills no problem. But taking off it is so bad till about 1600 rpm I need to do something about this any help would be great. Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-480801 Share on other sites More sharing options...
Joey Mack Posted October 3, 2021 Share Posted October 3, 2021 sounds like programming... the governor can be set to "all-speed" and it should perk up the throttle response, you have a great truck and the mileage is hard to believe... check fuel pressure and the condition of the fuel lines... at that age the lines are probably hard as a rock and need to be replaced... have you installed fresh fuel filters? lot's of Q's.... jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-480804 Share on other sites More sharing options...
OldRedMack Posted October 16, 2021 Share Posted October 16, 2021 Pressure check the intake, might have a blown intake manifold gasket. Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481416 Share on other sites More sharing options...
Jamkar Posted October 16, 2021 Share Posted October 16, 2021 Hey GOOG, did you ever get this sorted? Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481443 Share on other sites More sharing options...
GOOG Posted October 17, 2021 Author Share Posted October 17, 2021 JAMKAR, Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481508 Share on other sites More sharing options...
GOOG Posted October 17, 2021 Author Share Posted October 17, 2021 No, I haven't done anything with that truck. I ran her quite a bit this summer though. It is quite agrivating the way it lays down on you. I'm probably going to do a turbo and injectors and a new exhaust manifold on it this winter. Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481510 Share on other sites More sharing options...
Joey Mack Posted October 18, 2021 Share Posted October 18, 2021 Listen to me when I tell you this...... Do not take it apart before you research the availablity of the parts... I built and 05' this summer and the exh. manifold was not available til november, and the cost was high.. the intake manifold bolts that have the studded ends for the a/c bracket were not available, when buying engine parts, try to use the 11GBA number on the valve cover so that you get the right parts... I do this sh$t every week, and parts B.S. is more work than making the repair... Jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481512 Share on other sites More sharing options...
fjh Posted October 18, 2021 Share Posted October 18, 2021 I Second and third that ! If the truck is running wait till the parts are in your hands and are accounted for ! Specially Worse These days the parts chain is so messed up by the pandemic shit going on! LIsten GOOD! 1 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481531 Share on other sites More sharing options...
Joey Mack Posted October 18, 2021 Share Posted October 18, 2021 GOOG.... when/if the time comes you have to take it apart... if you have the time, come here with what you think is wrong and what you need to do. There are a few of us that will guide you , and help you put a basic parts list together, and offer suggestions and options on how to get it done. The parts issue is real, and folks like me have to have a crystal ball and X-Ray vision, before we dig in... In the Olden days, 2-4 years ago, it was much less of a hassle. Anyway, stay in touch... Lot's of smart guy's here.... jojo Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481544 Share on other sites More sharing options...
GOOG Posted October 20, 2021 Author Share Posted October 20, 2021 Ten4 Quote Link to comment https://www.bigmacktrucks.com/topic/61283-power-lag-on-2003-e7-400/#findComment-481621 Share on other sites More sharing options...
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