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Truck runs...won't accelerate..


Dan2014

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1999 Mack, ch613



I just did in frame overhaul. It starts and runs great!! But... won't accelerate. I press pedal to give it more diesel and it won't do anything. Just sits and idles. Anyone have any ideas??


Only thing on dash says...... Electronic Malfunction



Thanks!!!



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On a 99 ch it could have been an etech or a vmac e7, need to get that narrowed down for sure. Most likely culprit on an etech is the throttle pedal wiring, on a vmac e7 would be the pump wiring around the Bosch connector near the pump.

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I have checked for loose or corroded wires and connectors. I have checked foot pedal. It there anyway I can check for fire to sensor at pedal to see if sensor working? I never messed with any of this stuff doin the inframe overhaul. I am puzzled over all this. Any help will be greatly appreciated.

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I thought by 99 they were all ETECH engines.

ya know I believe your right, i think it was the 97's we had that were VMAC pump trucks not 99's.

"Any Society that would give up a little LIBERTY to gain a little SECURITY will Deserve Neither and LOSE BOTH" -Benjamin Franklin

"If your gonna be STUPID, you gotta be TOUGH"

"You cant always get what you want, but if you try sometimes you get what you need"

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Throttle is likely ether a varible resistance switch or potentiameter (sp?). To check a variable resistance switch you need a multimeter set to ohms (not sure the range) and hook the leads to the throttle wires and test resistance from idle to WOT....some one here might have the values for high/low.....infinite resistance indicates an open circuit.....

Lack of planning on your part does not constitute an emergency on my part....

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If its showing a 6-4 code and the idle is at 900 rpm and the throttle pedal wont respond then it really has nothing to do with the throttle pedal. As some one said above the 1939 wires are messes up some where. If the trans was pulled, there is also 1939 wires on top of the trans in thoses years.

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  • 6 years later...

Hi my truck go only 15mph but it change gear very well only when I change to 6 gear or more it make a little noise and I change the speed sensor the engine light go off but doesn’t drive no more then 15mph it 9400i international 2007 ixs does some one know what cause that cause i put a computer on it every it ok I mean engine turbo ejr 

Edited by Moise
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Check all the fuses for the engine and vehicle ecu first, an offline vmac module will set this code. The 6-4 code you are referring too is the J1939. This is used for communication between the engine ecu and the vehicle ecu (both vmac3 modules). The other modules plug into the backbone of the J1939 (auto trans, abs, and any other module). The vmac3 system did not have any external terminating resistors. They were built into the vecu and the engine ecu. To check the datalink, find the datalink connector, its under the dash on the driver side, beside the steering shaft. Disconnect the batteries, with your multimeter set to resistance, probe pins C and D. You should get 60 ohms. if its at 110 or 120 then you have an open circuit. The terminating resistors have a value of 120 ohms each. When they are connected in parallel the resistance goes to 60 ohms. 

Let us know what you find. 

V

Vmac J1939.png

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Just a thought.. is there a 6-5 code??? I think thats throttle pedal, wasnt there a re-set procedure in V-Mac soft , where you had to press the pedal three times to calibrate it? sometimes I had to do it a few times before it took.. yes I did this when re-programming a new E.C.M., just curious... Jojo

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You 2 Guys (Vmac3 & Joey Mack) do realise you've answered a 6 yr Old Question..??

 

Great Info, & insight though. You can never beat experience.!!

 

Moise, Welcome.

It's a Bit hard to solve your ISX Problem given the Info Provided (especially on a Mack Forum !!) Like Most things though. Best to start with the Simple little things First & work your way up from there.!

 

How long since you've changed the Fuel Filter??

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