tshirtliff

Sorry i messed up trying to reply a Qual-comm. is a satillite tracking and reporting system it just reads info off of the computor It was disconnected for any computor change overs and tests. This truck dosent have a pto system, so I presume the torque limit switch would be a computor entry only,and have to be checked in static shop mode i remember the mechanic told me he had checked it. And yes the vecu was also installed off the working truck and all were programed to my serial number as well as a substitute serial number no horse power improvement was found.

14V is fine!

(Qual-com installed)

WHAT IS THIS?

Doest it interface with the eecu OR vecu?

If so Remove it temperarly! (somthing to try)

When they checked torque limit did they do it running on the dyno in hi and low? Or just sitting in the shop static?

I have had the wiring to the torque limit switch rub and short (cuts the power in half) the best way to eliminate this is to find and pull the wires that monitor that circit at the VECU This way It will always be off FOR SURE!

Were the fuel threseholds checked?

I do simpthize Ive had to fight these things before !only been stumped a few times this is just another to add to my list!

I don't see the magic bullet here either !they did everything possible in my mind, ecu swap from a good known unit should have done the trick if the ecu was at fault! having said that! (I know you said ALL working computers) from a good known unit were installed ) but did they swap out the VECU as well? Maybe the EECU is seeing somthing it doesent like there?Somtimes the simplest things can be overlooked. The eecu is getting a message from somthing in the vecu to tell it to hold out on ya!Somthing it dosent see as a problem but A normal operation hold out! The only ones I can think of were the torque limilt and road speed functions!

Sorry Man Im stumped AS well !

Let Us know if you get it !

I'll let you know if I can think of anything else!

the truck drove and preformed great was pulling a load and a loud knock started found it was a failed cam shaft. decided to replace motor for a time saving value. a reman was installed with my jakes, turbo(35lb), fuel pump, injectors, unit pumps, starter, compressor, a/c, and the new add-ons inclued new altenator, water pump, oil cooler. since i got the truck back it will only put out 19 lbs boost, and the pyro even on a big hill,pulling a 80000 lbs load wont climb above 750 degrees, and motor temp wont go above 200. The fuel pressure is at 75 lbs, we had a shop computor installed and programed to the unit pumps, new unit pumps were installed and no change (after removed) a new turbo was installed and again no change(removed after) all working computors off of another truck were tried with no improvement. then mack decided it was time to look inside they found the pistons were right the heads were right and working (not sticking),the cam was right and all the timeing and internal settings were right. all the sensors were functioning, an external fuel source was used and that as well didnt make any difference, they concluded it wasnt the motor. After removing the other computors mine was reinstalled and found that it wouldnt reprogram after being flashed so i elected to have a new ecu installed when that didnt work they had no more ideas and sent me home to try to figure it out on my own. I have replaced the boost sensor and replaced input and output fuel lines to the secondary filter, with no change. I feel it must be electrical possibly the out put voltage to the sensors or the wiring harness was corruptted during the change over, or possiblly the new altenator was wired up wrong(14volts)? during all of this we have found the truck thinks it is getting more fuel that it is, it has a Qual-com installed and it consistently records higher fuel consumpution than what it refuels at by 5:3.5 ratio. I hope you can see where my frustation is comming from. thanks for your consideration.

Rider

Heres sone stuff to have em check! FIRST Have em look in diagnostics go to switch status look for torque limit see if the switch says on or off!!! Needs to be off!

You need to see 60 psi fuel preasure there abouts full load !

(you won't know this one unless you now the parts guy real well you bought the engine from.)

WHAT cam key is in the engine You need a white off set cam key installed in that engine to run right! If its wrong (It will be down to 25 psi boost and have no pull range)

Sounds like your exsactly half of what you should be so I would suspect the torque limit!!!

thanks for the respond. They had the motor apart and checked the key and position and say it was ok the diagnostics had been checked for torque limit and was in the off position as i said this has the experts stumped any other suggestions it goes back on the dyno at a different shop on tuesday

Ive come to this forum for some help. I have a 2000 cx613 with 460 18 spd I bought a mack reman and had it installed Result is very poor power the dealer and mack have spent 4 weeks trying to get my power back and have given up and sent me home with 230 hp and a lot of frustration more shifting than you can imagine. they have checked and double checked all that they can think of as a source of the problem. the last they told me was i was going to have to start throwing parts at it, cause it isn't their motor. my thoughts are that it might be electrical control of the engine preformance where do i start it is not getting enough fuel,it has low boost, low pyro temp, no smoke. All the major components have been changed or checked, turbo, unit pumps, pistons, cam shaft, air to air system, exhaust system, fuel supply, injectors, and all the computors, and sensors. Any suggestions? Im wondering where the 5 volt power supply for some of the sensors is generated, and what peramitors have to be read before the computor increases fuel volume to the injectors?