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About Onestitch

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  1. Found the switch ....under the dash above the fuel pedal
  2. My low air buzzer and light comes on at 110 psi. And they wont go off till they hit 110psi at start up . I have a 1993 RD688 and was wondering if anyone knows where the pressure switch is located at on these trucks .
  3. Ok been fighting this demon for almost a year on this truck I have replaced the Fic and had Mack dealer test my Vmac module when he reprogrammed my fic and it was all good ..well my truck still wont run ..ugh ..so my actuator is not working so run thru the actuator test and it all leads right up to test 64 ..when I perform the test the actuator wont move ..I put the voltage tester on the jumpers when performing the test and I have 12.75 volts F1 but when I touch E4 to ground the voltage just drops out to 0 from F1 and actuator dont move ...now if I touch the F1 and E4 jumpers directly to +an
  4. Hey Okiki I know this is a old thread but I have the exact same thing going on with my truck as you describe ..my test procedures from vmac manual leads right to bad actuator that dont move but when I put jumper leads to battery I can fire the truck right up ...so I am searching for bad ground like you had ...but my question is if my actuator is bad i see you said you replaced the electronic govenor ...where you able to pull that off and replace it without removing the injection pump from the truck or did you have to remove pump to change that govenor ?
  5. My actuator is bad on my vmac 1 E7 400 ,my question is can that actuator be replaced with out having to pull the whole P7100 fuel pump off and having to re time it .
  6. I can not get my 93 E7400 vmac1 to start ...tired of throwing $$$ at it ..it is not throwing any codes ,I put a new reconditioned Fic module in from Mack dealer and dealer tested my Vmac module on a truck when he had it to program my fic and said it works ...problem is my P7100 pump actuator does not move when I step on the fuel pedal like the manuel says it should ...I can put 12v to the actuator and it moves so it is not stuck ...do you guys think I need to pull the full pump and have it rebuilt ?
  7. I pulled and changed fuel filters and no start so I checked voltage at fuel shut off selenoid and I am not getting any voltage so think I found my problem but it is not showing any fault codes ...lightning bolt light only comes on for 3 seconds then goes off when I turn key on ...I try to retrieve codes thru the cruise control switch resume button but it dont show any faults and I image lightning bolt light would stay on when I turn the key if it was throwing a code or fault but it just comes on for 3 seconds and goes off
  8. I found it ...bulb was burned out ...lightning bolt lights up when I turn key for 3 seconds then goes off so I imagine computer is not throwing any codes I can retrieve ...this is stumping me because still no voltage at fuel shut off selenoid by the fuel pump ...
  9. Where is the fault lamp location at on the dash of the 1993 RD ...I think my bulb is burnt out because never comes on ...Is it locates right above cruise control switches ? Or is it located by the tach and speedometer ?
  10. Does any one know where the location of my 93 RD688 ecm is ...I believe it is a V Mac 1 ...
  11. My 1993 mack rd688 with the E7 400 will not start...can run it on starting fluid but will not run with out starting fluid so no fuel problem ...started by changing all the fuel filters and no start so I checked for voltage at the fuel shut down solenoid and nothing ...checked the shut down relay and it seems to be working and swapped it out with other relays that I know work and still no voltage at shut down solenoid ...the relay clicks when I turn key on or plug it in like all my other relays ...my question is there something else that will cause a fuel solenoid shut down ..like maybe ECU or
  12. I bought a 1993 Mack rd 688 E7 400 engine and the guy I bought from said it has all new injectors and it looks like all new fuel filters and truck would run and start great ..just bump the key and it would start right up ...then it slowly got to where it would start taking longer cranking to start but it would run great when running ...went to start yesterday and cranks but no start ...it will run on starting fluid but then die ...tank is 3/4 full of diesel...were should I start trouble shooting this ? Pull the fuel filters and check for full ? How do I test the fuel pump or transfer pump ? A
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