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POWER LAG ON 2003 E7-400


GOOG
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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?  

2003 RD688SX.jpg

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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 by fjh
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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 by Mack Technician
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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!

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 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.  

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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 by Mack Technician
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  • 1 year later...

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. 

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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

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  • 2 weeks later...

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.  

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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 

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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! 

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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

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