Al Colussi Posted February 16, 2013 Share Posted February 16, 2013 (edited) I have a code 8-1 and sometimes a code 8-3.... Any ideas???Thanks Edited February 16, 2013 by al colussi Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/ Share on other sites More sharing options...
Challenger Posted February 16, 2013 Share Posted February 16, 2013 (edited) Vmac III 8-1 EUP #18-3 EUP #3Do you notice a miss with the codes? Probably need to replace the EUPs that have the active code. Here is a quick reference for blink codes.http://www.auroramack.com/pdf/308/V-MAC%20Fault%20Assignments.pdf Edited February 16, 2013 by Challenger Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165000 Share on other sites More sharing options...
Al Colussi Posted February 17, 2013 Author Share Posted February 17, 2013 Nothing I would call a dead miss or total loss of any one cylinder, however pulling a hill loaded there is an rpm drop that comes and goes. Just when it seems like the truck is going to take off and pull strong, all of the sudden an rpm loss will occur. It may only last between 3 and 7 seconds and then the engine will pick back up. The light is usually not on at this point. I seem to see the light first thing in the morning and that about it for the day. When the light comes on during morning warm up I will read the codes at that point, like I said sometimes an 8-1 sometimes an 8-3. I was hoping for a wiring connection or some corrosion issue. Probably cant get that lucky. Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165226 Share on other sites More sharing options...
staxx Posted February 17, 2013 Share Posted February 17, 2013 Check the wiring under the unit pump covers as the wiring gets old it gets brittle make sure that they are not rubbing against the cover or block . Unplug module and check pins for debris or coolant/oil/rust . You could also remove and swap unit pump to a differant cylinder to confirm that unit pump has failed. Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165293 Share on other sites More sharing options...
Challenger Posted February 17, 2013 Share Posted February 17, 2013 The throttle dropping in and out could be a software issue. If you ever take it to a dealer tell them to flash and reprogram the EECU and VECU. Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165317 Share on other sites More sharing options...
staxx Posted February 17, 2013 Share Posted February 17, 2013 Dropping out could be almost anything shorted alt , block ground , fuel psi ,unit pump, throttle pedal , power relay 1-4 ...... hummmm where to start ? Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165333 Share on other sites More sharing options...
Al Colussi Posted February 17, 2013 Author Share Posted February 17, 2013 Thanks for the input. The company I work for is not likely to spend any substantial dollars just so I can go up hills faster. But you guys gave me some suggestions that I can try myself and I appreciate that very much.THANKS!!! Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165399 Share on other sites More sharing options...
Challenger Posted February 18, 2013 Share Posted February 18, 2013 Dropping out could be almost anything shorted alt , block ground , fuel psi ,unit pump, throttle pedal , power relay 1-4 ...... hummmm where to start ?Flashing and reprogramming the EECU and VECU is always a win-win for the truck. Even if it doesnt repair the problem it definitely wont hurt it. People who never take their trucks to dealer will most likely have some type of software update. Im a big fan of updating software levels. Out with old, in with the new. Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165439 Share on other sites More sharing options...
staxx Posted February 18, 2013 Share Posted February 18, 2013 This is a common problem most likey reflash will not fix might get better throttle response if this is older 2001-2004 model Quote Link to comment https://www.bigmacktrucks.com/topic/29969-v-mac-code-8-1/#findComment-165445 Share on other sites More sharing options...
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